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Sample records for additional optical elements

  1. Additive manufacturing of optical components

    NASA Astrophysics Data System (ADS)

    Heinrich, Andreas; Rank, Manuel; Maillard, Philippe; Suckow, Anne; Bauckhage, Yannick; Rößler, Patrick; Lang, Johannes; Shariff, Fatin; Pekrul, Sven

    2016-08-01

    The development of additive manufacturing methods has enlarged rapidly in recent years. Thereby, the work mainly focuses on the realization of mechanical components, but the additive manufacturing technology offers a high potential in the field of optics as well. Owing to new design possibilities, completely new solutions are possible. This article briefly reviews and compares the most important additive manufacturing methods for polymer optics. Additionally, it points out the characteristics of additive manufactured polymer optics. Thereby, surface quality is of crucial importance. In order to improve it, appropriate post-processing steps are necessary (e.g. robot polishing or coating), which will be discussed. An essential part of this paper deals with various additive manufactured optical components and their use, especially in optical systems for shape metrology (e.g. borehole sensor, tilt sensor, freeform surface sensor, fisheye lens). The examples should demonstrate the potentials and limitations of optical components produced by additive manufacturing.

  2. CONTROL OF LASER RADIATION PARAMETERS: Compensation for thermally induced aberrations in optical elements by means of additional heating by CO2 laser radiation

    NASA Astrophysics Data System (ADS)

    Soloviev, A. A.; Kozhevatov, I. E.; Palashov, O. V.; Khazanov, E. A.

    2006-10-01

    A method is proposed for compensating thermally induced phase distortions of laser radiation in absorbing optical elements. The method is based on supplementary heating of the peripheral region of the distorting element by the radiation from an auxiliary laser. A programme code has been developed for calculating the optimal parameters of supplementary radiation for minimising phase distortions. This code is based on the numerical solution of the thermal conductivity and static elasticity equations for a nonuniformly heated solid of cylindrical symmetry. Experiments reveal a high efficiency of the method for compensating distortions resulting from absorption of radiation with a Gaussian intensity profile.

  3. Optics of progressive addition lenses.

    PubMed

    Sheedy, J E; Buri, M; Bailey, I L; Azus, J; Borish, I M

    1987-02-01

    The optical characteristics of the major progressive addition lenses were measured using an automated lensometer with a specially designed lens holder to simulate eye rotation. Measurements were made every 3 degrees (about 1.5 mm) and graphs of isospherical equivalent lines and isocylinder lines were developed. Generally the near zone of these lenses is narrower and lower than in bifocal or trifocal lenses. Distinct differences exist between the various progressive lenses. The width of the near zone, rate of power progression, amount of unwanted cylinder (level with the distance center), and clarity of the distance zone are compared for the various lenses. The optical measurements demonstrate an apparent trade-off between the size of the cylinder-free area of the lens and the amount of the cylinder.

  4. Evaluation of Hologram Optical Elements

    DTIC Science & Technology

    1975-06-01

    SUMMARY This report is the third in a series th?c cover the investigation of the properties and applications of holo- graphic optics. This type of...Design gy 6.2. Fabrication 97 7. Single Hologram Element Properties 101 7.1. Selection of Study Parameters 101 7.2. Case 1: Q...the Important Cases to be Analyzed in the Single Hologram Element Properties Study. . .106 14 mammiammtii . •MMaWaaaiuuia ttttmrngUdttt^Mi

  5. Analysis of thermally loaded transmissive optical elements

    NASA Astrophysics Data System (ADS)

    Michels, Gregory J.; Genberg, Victor L.

    2013-09-01

    The performance metrics of many optical systems are affected by temperature changes in the system through different physical phenomena. Temperature changes cause materials to expand and contract causing deformations of optical components. The resulting stress states in transmissive optics can cause refractive changes that can affect optical performance. In addition, the temperature changes themselves can cause changes in the refractive properties of transmissive optics. Complex distributions of refractive indices that relate to the thermal profile, the thermo-optic refractive index profile, within the optical media can be predicted by the finite element method. One current technique for representing such refractive index profiles is through the generation of optical path difference (OPD) maps by integration along integration paths. While computationally efficient, this method has limitations in its ability to represent the effect of the index changes for rays associated with multiple field points and multiple wavelengths. A more complete representation of the thermo-optic refractive index profile may be passed to the optical analysis software through the use of a user defined gradient index material. The interface consists of a dynamic link library (DLL) which supplies indices of refraction to a user defined gradient index lens as ray tracing calculations are being performed. The DLL obtains its refractive index description from a database derived from the thermal analysis of the optics. This process allows optical analysis software to perform accurate ray tracing for an arbitrary refractive index profile induced by changes in temperature.

  6. Method of lightening radiation darkened optical elements

    DOEpatents

    Reich, Frederich R.; Schwankoff, Albert R.

    1980-01-01

    A method of lightening a radiation-darkened optical element in wich visible optical energy or electromagnetic radiation having a wavelength in the range of from about 2000 to about 20,000 angstroms is directed into the radiation-darkened optical element; the method may be used to lighten radiation-darkened optical element in-situ during the use of the optical element to transmit data by electronically separating the optical energy from the optical output by frequency filtering, data cooling, or interlacing the optic energy between data intervals.

  7. Design of multifunctional diffractive optical elements

    NASA Astrophysics Data System (ADS)

    Vijayakumar, Anand; Bhattacharya, Shanti

    2015-02-01

    Diffractive optics has traditionally been used to transform a parallel beam of light into a pattern with a desired phase and intensity distribution. One of the advantages of using diffractive optics is the fact that multiple functions can be integrated into one element. Although, in theory, several functions can be combined, the efficiency is reduced with each added function. Also, depending on the nature of each function, feature sizes could get finer. Optical lithography with its 1 μm limit becomes inadequate for fabrication and sophisticated tools such as e-beam lithography and focused ion beam milling are required. Two different techniques, namely, a modulo-2π phase addition technique and an analog technique for design and fabrication of composite elements are studied. A comparison of the beams generated in both cases is presented. In order to be able to compare methods, specific functions of ring generation and focusing have been added in all cases.

  8. Stratified volume diffractive optical elements

    NASA Astrophysics Data System (ADS)

    Chambers, Diana Marie

    2000-11-01

    Gratings with high diffraction efficiency into a single order find use in applications ranging from optical interconnects to beam steering. Such gratings have been realized with volume holographic, blazed, and diffractive optical techniques. However, each of these methods has limitations that restrict the range of applications in which they can be used. In this work an alternate, novel approach and method for creating high efficiency gratings has been developed. These new gratings are named stratified volume diffractive optical elements (SVDOE's). In this approach diffractive optic techniques are used to create an optical structure that emulates volume grating behavior. An SVDOE consists of binary gratings interleaved with homogeneous layers in a multi-layer, stratified grating structure. The ridges of the binary gratings form fringe planes analogous to those of a volume hologram. The modulation and diffraction of an incident beam, which occur concurrently in a volume grating, are achieved sequentially by the grating layers and the homogeneous layers, respectively. The layers in this type of structure must be fabricated individually, which introduces the capability to laterally shift the binary grating layers relative to one another to create a grating with slanted fringe planes. This allows an element to be designed with high diffraction efficiency into the first order for any arbitrary angle of incidence. A systematic design process has been developed for SVDOE's. Optimum modulation depth of the SVDOE is determined analytically and the number of grating layers along with the thickness of homogeneous layers is determined by numerical simulation. A rigorous electromagnetic simulation of the diffraction properties of multi-layer grating structures, based on the Rigorous Coupled-Wave Analysis (RCWA) algorithm, was developed and applied to SVDOE performance prediction. Fabrication of an SVDOE structure presents unique challenges. Microfabrication combined with

  9. Optical Element, Device, Method, and Applications

    DTIC Science & Technology

    2011-04-14

    optical element is a phase-only element; and h) repeating steps ( c -f). 28. The method of claim 26, further comprising: c1) in step (c), setting...jl(l;, 11) to 0, wherein the optical element is an amplitude-only element; and h) repeating steps ( c -f). * * * * *

  10. Tool Releases Optical Elements From Spring Brackets

    NASA Technical Reports Server (NTRS)

    Gum, J. S.

    1984-01-01

    Threaded hooks retract bracket arms holding element. Tool uses three hooks with threaded shanks mounted in ring-shaped holder to pull on tabs to release optical element. One person can easily insert or remove optical element (such as prism or lens) from spring holder or bracket with minimal risk of damage.

  11. Investigation of uses of holographic optical elements

    NASA Technical Reports Server (NTRS)

    Zech, R. G.; Latta, J. N.

    1973-01-01

    The data represent a thorough study of the aberrations and imaging properties of holographic optical elements. Principle studies include (1) the indepth experimental investigation of single holographic optical elements, (2) the verification of the accuracy of the theoretical computer-based description of hologram behavior, (3) the computer-generation of interferograms that are characteristic of a prescribed aberrated imaging condition, (4) the experimental verification of wavelength optimization, (5) the experimental determination of the space bandwidth product of single holographic optical elements as a function of bending and field angle, and (6) the first experimental study of the aberration properties of holographic optical elements constructed in very thick (750 microns) recording media.

  12. Two position optical element actuator device

    DOEpatents

    Holdener, Fred R.; Boyd, Robert D.

    2002-01-01

    The present invention is a two position optical element actuator device utilizing a powered means to hold an actuation arm, to which an optical element is attached, in a first position. A non-powered means drives the actuation arm to a second position, when the powered means ceases to receive power. The optical element may be a electromagnetic (EM) radiation or particle source, an instrument, or EM radiation or particle transmissive, reflective or absorptive elements. A bearing is used to transfer motion and smoothly transition the actuation arm from the first to second position.

  13. Bi-stable optical element actuator device

    DOEpatents

    Holdener, Fred R.; Boyd, Robert D.

    2002-01-01

    The present invention is a bistable optical element actuator device utilizing a powered means to move an actuation arm, to which an optical element is attached, between two stable positions. A non-powered means holds the actuation arm in either of the two stable positions. The optical element may be a electromagnetic (EM) radiation or particle source, an instrument, or EM radiation or particle transmissive reflective or absorptive elements. A bearing is used to transfer motion and smoothly transition the actuation arm between the two stable positions.

  14. Holographic optical elements: Fabrication and testing

    NASA Technical Reports Server (NTRS)

    Zech, R. G.; Shareck, M.; Ralston, L. M.

    1974-01-01

    The basic properties and use of holographic optical elements were investigated to design and construct wide-angle, Fourier-transform holographic optical systems for use in a Bragg-effect optical memory. The performance characteristics are described along with the construction of the holographic system.

  15. Optically intraconnected computer employing dynamically reconfigurable holographic optical element

    NASA Technical Reports Server (NTRS)

    Bergman, Larry A. (Inventor)

    1992-01-01

    An optically intraconnected computer and a reconfigurable holographic optical element employed therein. The basic computer comprises a memory for holding a sequence of instructions to be executed; logic for accessing the instructions in sequence; logic for determining for each the instruction the function to be performed and the effective address thereof; a plurality of individual elements on a common support substrate optimized to perform certain logical sequences employed in executing the instructions; and, element selection logic connected to the logic determining the function to be performed for each the instruction for determining the class of each function and for causing the instruction to be executed by those the elements which perform those associated the logical sequences affecting the instruction execution in an optimum manner. In the optically intraconnected version, the element selection logic is adapted for transmitting and switching signals to the elements optically.

  16. 3D-additive manufactured optical mount

    NASA Astrophysics Data System (ADS)

    Mammini, Paul V.; Ciscel, David; Wooten, John

    2015-09-01

    The Area Defense Anti-Munitions (ADAM) is a low cost and effective high power laser weapon system. It's designed to address and negate important threats such as short-range rockets, UAVs, and small boats. Many critical optical components operate in the system. The optics and mounts must accommodate thermal and mechanical stresses, plus maintain an exceptional wave front during operation. Lockheed Martin Space Systems Company (LMSSC) developed, designed, and currently operates ADAM. This paper covers the design and development of a key monolithic, flexured, titanium mirror mount that was manufactured by CalRAM using additive processes.

  17. Additive manufacturing of glass for optical applications

    NASA Astrophysics Data System (ADS)

    Luo, Junjie; Gilbert, Luke J.; Bristow, Douglas A.; Landers, Robert G.; Goldstein, Jonathan T.; Urbas, Augustine M.; Kinzel, Edward C.

    2016-04-01

    Glasses including fused quartz have significant scientific and engineering applications including optics, communications, electronics, and hermetic seals. This paper investigates a filament fed process for Additive Manufacturing (AM) of fused quartz. Additive manufacturing has several potential benefits including increased design freedom, faster prototyping, and lower processing costs for small production volumes. However, current research in AM of glasses is limited and has focused on non-optical applications. Fused quartz is studied here because of its desirability for high-quality optics due to its high transmissivity and thermal stability. Fused quartz also has a higher working temperature than soda lime glass which poses a challenge for AM. In this work, fused quartz filaments are fed into a CO2 laser generated melt pool, smoothly depositing material onto the work piece. Single tracks are printed to explore the effects that different process parameters have on the morphology of printed fused quartz. A spectrometer is used to measure the thermal radiation incandescently emitted from the melt pool. Thin-walls are printed to study the effects of layer-to-layer height. Finally, a 3D fused quartz cube is printed using the newly acquired layer height and polished on each surface. The transmittance and index homogeneity of the polished cube are both measured. These results show that the filament fed process has the potential to print fused quartz with optical transparency and of index of refraction uniformity approaching bulk processed glass.

  18. Method and apparatus for staking optical elements

    DOEpatents

    Woods, Robert O.

    1988-10-04

    A method and apparatus for staking two optical elements together in order to retain their alignment is disclosed. The apparatus includes a removable adaptor made up of first and second adaptor bodies each having a lateral slot in their front and side faces. The adaptor also includes a system for releasably attaching each adaptor body to a respective optical element such that when the two optical elements are positioned relative to one another the adaptor bodies are adjacent and the lateral slots therein are aligned to form key slots. The adaptor includes keys which are adapted to fit into the key slots. A curable filler material is employed to retain the keys in the key slots and thereby join the first and second adaptor bodies to form the adaptor. Also disclosed is a method for staking together two optical elements employing the adaptor of the present invention.

  19. Method and apparatus for staking optical elements

    DOEpatents

    Woods, Robert O.

    1988-01-01

    A method and apparatus for staking two optical elements together in order to retain their alignment is disclosed. The apparatus includes a removable adaptor made up of first and second adaptor bodies each having a lateral slot in their front and side faces. The adaptor also includes a system for releasably attaching each adaptor body to a respective optical element such that when the two optical elements are positioned relative to one another the adaptor bodies are adjacent and the lateral slots therein are aligned to form key slots. The adaptor includes keys which are adapted to fit into the key slots. A curable filler material is employed to retain the keys in the key slots and thereby join the first and second adaptor bodies to form the adaptor. Also disclosed is a method for staking together two optical elements employing the adaptor of the present invention.

  20. Passive optical element with selective angular reflection.

    PubMed

    Tremblay, C; Rheault, F; Boulay, R; Tremblay, R

    1987-02-01

    This work is related to the development of passive selective transmission materials that will contribute to regularize the solar thermal gain. We propose an original solution to the problem of seasonal control of energetic input into buildings through windows. A passive optical element with selective angular reflection is used to solve this problem. This optical element allows sunlight to enter windows during the fall and winter, whereas, owing to the different astronomical path of the sun, it stops and rejects direct sunlight by means of the optical effect called total internal reflection (TIR) during the central spring-summer period. The purpose of this paper is to describe the optical element in some detail, to develop the principal design equations, and give the results of the optimization of optical and geometrical parameters.

  1. Sputter metalization of Wolter type optical elements

    NASA Technical Reports Server (NTRS)

    Ledger, A. M.

    1977-01-01

    An analytical task showed that the coating thickness distribution for both internal and external optical elements coated using either electron beam or sputter sources can be made uniform and will not affect the surface figure of coated elements. Also, sputtered samples of nickel, molybdenum, iridium and ruthenium deposited onto both hot and cold substrates showed excellent adhesion.

  2. Grinding technologies of small optical element molds

    NASA Astrophysics Data System (ADS)

    Katsuki, Masahide; Urushibata, Kazunori

    2003-05-01

    The high-precision grinding technology is making contribution in every field, which is especially remarkable in the optics-related field. Lenses for digital camera and projector, which are mass-produced, for instance, are molded by the injection molding machine and glass molding-press machine. Concerning materials of high-precision molds, nickel alloy is mainly used in plastic-molding. And brittle material such as tungsten carbide and ceramic is used in glass-molding because the molding temperature is generally high. High-precision machining of nickel alloy is possible with a single-crystal diamond tool. Brittle material is ground by means of a diamond wheel, etc. Glass is being widely used for the lenses and other optical elements due to its favorable characteristics and life. As a result, needs for advancement of the high-precision grinding technology are being heightened. In grinding of small, fine and complex profiles, consideration for wheel truing and wear is a key point. Also, as many optical mold products are convex, mold profile is mainly concave. Especially, grinding of a small-aperture mold with small radius of curvature is difficult. In other words, a wheel whose diameter is larger than the radius of curvature of a mold to be ground cannot be used, and use of a small-diameter wheel is required inevitably. Influence of wheel wear and wheel diameter input errors at creation of grinding program becomes large. To eliminate such errors, a cycle of grinding, measurement and compensation grinding is normally repeated in mold machining until the target accuracy is obtained. Recently, needs for molding optical elements of small body of non-revolution such as prism and cylinder lens are on the increase, in addition to the body of revolution including lens. As one example, we introduce the compensation grinding and its results when grinding molds for an extremely small-aperture lens used for optical communication and a cylindrical lens array used for semi

  3. Performance of MEGARA spectrograph optical elements

    NASA Astrophysics Data System (ADS)

    Carrasco, E.; Páez, G.; Izazaga, R.; de la Luz Hurtado, J.; Pérez, C.; Granados, F.; Aguirre, D.; Percino, E.; Reyes, J.; Gil de Paz, A.; Gallego, J.; Iglesias, J.

    2016-08-01

    MEGARA is the new IFU and multiobject spectrograph for Gran Telescopio Canarias. The spectograph will offer spectral resolution Rfwhm 6,000, 12,000 and 18,700. Except for the optical fibers and microlenses, the complete MEGARA optical system has been manufactured in Mexico. This includes a field lens, a 5-lenses collimator, a 7-lenses camera and a complete set of volume phase holographic gratings with 36 flat windows and 24 prisms. All these elements are very large and complex, with very efficient antireflection coatings. Here the optical performance of MEGARA collimator and camera lenses and the field lens is presented.

  4. Survivable virtual optical network embedding with probabilistic network-element failures in elastic optical networks

    NASA Astrophysics Data System (ADS)

    Yang, Hui; Cheng, Lei; Luo, Guangjun; Zhang, Jie; Zhao, Yongli; Ding, Huixia; Zhou, Jing; Wang, Yang

    2015-06-01

    The elastic optical networks can elastically allocate spectrum tailored for various bandwidth requirements. In addition, different virtual optical networks (VONs) formed by different applications or service providers need to be embedded on the common physical optical network, it brings virtual optical network embedding (VONE) problem. There is no precise standard to measure the survivability of VON from the failure probability view and take minimum VON failure probability as an objective in a VONE problem. In this paper, we investigate a survivable VONE problem from a new perspective. Considering probabilistic physical network-element failures, a novel metric, named virtual optical network failure probability (VON-FP), is introduced to evaluate the survivability of VONs in elastic optical networks. Moreover, a failure-probability-aware virtual optical network embedding (FPA-VONE) algorithm is proposed to deploy VONs on the physical network elements with small failure probability, and finally to decrease the VON-FP and enhance the spectrum utilization effectively.

  5. Special diffractive elements for optical trapping fabricated on optical fiber tips using the focused ion beam

    NASA Astrophysics Data System (ADS)

    Rodrigues Ribeiro, R. S.; Guerreiro, A.; Viegas, J.; Jorge, P. A. S.

    2016-05-01

    In this work, spiral phase lenses and Fresnel zone lenses for beam tailoring, fabricated on the tip of optical fibers, are reported. The spiral phase lenses allow tailoring the fundamental guided mode, a Gaussian beam, into a Laguerre - Gaussian profile without using additional optical elements. Whereas, the Fresnel lenses are used as focusing systems. The lenses are fabricated using Focused Ion Beam milling, enabling high resolution in the manufacturing process. The output optical intensity profiles matching the numerical simulations are presented and analyzed.

  6. Method and system for processing optical elements using magnetorheological finishing

    DOEpatents

    Menapace, Joseph Arthur; Schaffers, Kathleen Irene; Bayramian, Andrew James; Molander, William A

    2012-09-18

    A method of finishing an optical element includes mounting the optical element in an optical mount having a plurality of fiducials overlapping with the optical element and obtaining a first metrology map for the optical element and the plurality of fiducials. The method also includes obtaining a second metrology map for the optical element without the plurality of fiducials, forming a difference map between the first metrology map and the second metrology map, and aligning the first metrology map and the second metrology map. The method further includes placing mathematical fiducials onto the second metrology map using the difference map to form a third metrology map and associating the third metrology map to the optical element. Moreover, the method includes mounting the optical element in the fixture in an MRF tool, positioning the optical element in the fixture; removing the plurality of fiducials, and finishing the optical element.

  7. Diffractive optical elements written by photodeposition

    NASA Astrophysics Data System (ADS)

    Baal-Zedaka, I.; Hava, S.; Mirchin, N.; Margolin, R.; Zagon, M.; Lapsker, I.; Azoulay, J.; Peled, A.

    2003-03-01

    In this work direct laser writing of diffractive optical elements (DOE) by photodeposition (PD) of amorphous selenium (a-Se) from colloid solutions has been investigated. We used a computer controlled laser scanner for patterning thin film micro-profiles creating thus planar optical elements by direct beam writing on surfaces immersed in a liquid phase PD cell. The laser employed was an argon ion laser at 488 nm wavelength, with powers up to 55 mW, for writing typically 25-250 μm wide lines of 200 nm thickness at rates of about 150 μm/s. Various elements made of photodeposited thin films on polymethyl-methacrylate (PMMA) substrates were produced for prototyping microlenses, linear grating arrays, cylindrical and circular profiled DOE patterns.

  8. Optical sensing: recognition elements and devices

    NASA Astrophysics Data System (ADS)

    Gauglitz, Guenter G.

    2012-09-01

    The requirements in chemical and biochemical sensing with respect to recognition elements, avoiding non-specific interactions, and high loading of the surface for detection of low concentrations as well as optimized detection systems are discussed. Among the many detection principles the optical techniques are classified. Methods using labeled compounds like Total Internal Reflection Fluorescence (TIRF) and direct optical methods like micro reflectometry or refractometry are discussed in comparison. Reflectometric Interference Spectroscopy (RIfS) is presented as a robust simple method for biosensing. As applications, trace analysis of endocrine disruptors in water, hormones in food, detection of viruses and bacteria in food and clinical diagnostics are discussed.

  9. X-ray monitoring optical elements

    SciTech Connect

    Stoupin, Stanislav; Shvydko, Yury; Katsoudas, John; Blank, Vladimir D.; Terentyev, Sergey A.

    2016-12-27

    An X-ray article and method for analyzing hard X-rays which have interacted with a test system. The X-ray article is operative to diffract or otherwise process X-rays from an input X-ray beam which have interacted with the test system and at the same time provide an electrical circuit adapted to collect photoelectrons emitted from an X-ray optical element of the X-ray article to analyze features of the test system.

  10. Holographic Optical Elements as Scanning Lidar Telescopes

    NASA Technical Reports Server (NTRS)

    Schwemmer, Geary K.; Rallison, Richard D.; Wilkerson, Thomas D.; Guerra, David V.

    2003-01-01

    We have investigated and developed the use of holographic optical elements (HOE) and holographic transmission gratings for scanning lidar telescopes. By rotating a flat HOE in its own plane with the focal spot on the rotation axis, a very simple and compact conical scanning telescope is possible. We developed and tested transmission and reflection HOES for use with the first three harmonics of Nd:YAG lasers, and designed, built, and tested two lidar systems based on this technology.

  11. Holographic optical elements as scanning lidar telescopes

    NASA Astrophysics Data System (ADS)

    Schwemmer, Geary K.; Rallison, Richard D.; Wilkerson, Thomas D.; Guerra, David V.

    2006-09-01

    We have developed and investigated the use of holographic optical elements (HOEs) and holographic transmission gratings for scanning lidar telescopes. Rotating a flat HOE in its own plane with the focal spot on the rotation axis makes a very simple and compact conical scanning telescope. We developed transmission and reflection HOEs for use at the first three harmonic wavelengths of Nd:YAG lasers. The diffraction efficiency, diffraction angle, focal length, focal spot size and optical losses were measured for several HOEs and holographic gratings, and found to be suitable for use as lidar receiver telescopes, and in many cases could also serve as the final collimating and beam steering optic for the laser transmitter. Two lidar systems based on this technology have been designed, built, and successfully tested in atmospheric science applications. This technology will enable future spaceborne lidar missions by significantly lowering the size, weight, power requirement and cost of a large aperture, narrow field of view scanning telescope.

  12. Polishing techniques for MEGARA pupil elements optics

    NASA Astrophysics Data System (ADS)

    Izazaga, R.; Carrasco, E.; Aguirre, D.; Salas, A.; Gil de Paz, A.; Gallego, J.; Iglesias, J.; Arroyo, J. M.; Hernández, M.; López, N.; López, V.; Quechol, J. T.; Salazar, M. F.; Carballo, C.; Cruz, E.; Arriaga, J.; De la Luz, J. A.; Huepa, A.; Jaimes, G. L.; Reyes, J.

    2016-07-01

    MEGARA (Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía) is the new integral-field and multi-object optical spectrograph for the 10.4m Gran Telescopio Canarias.. It will offer RFWHM 6,000, 12,000 and 18,700 for the low- , mid- and high-resolution, respectively in the wavelength range 3650-9700Å. .The dispersive elements are volume phase holographic (VPH) gratings, sandwiched between two flat Fused Silica windows of high optical precision in large apertures. The design, based in VPHs in combination with Ohara PBM2Y prisms allows to keep the collimator and camera angle fixed. Seventy three optical elements are being built in Mexico at INAOE and CIO. For the low resolution modes, the VPHs windows specifications in irregularity is 1 fringe in 210mm x 170mm and 0.5 fringe in 190mm x 160mm. for a window thickness of 25 mm. For the medium and high resolution modes the irregularity specification is 2 fringes in 220mm x 180mm and 1 fringe in 205mm x 160mm, for a window thickness of 20mm. In this work we present a description of the polishing techniques developed at INAOE optical workshop to fabricate the 36 Fused Silica windows and 24 PBM2Y prisms that allows us to achieve such demanding specifications. We include the processes of mounting, cutting, blocking, polishing and testing.

  13. A multilevel optical element based on the Fizeau multibeam interferometer

    NASA Astrophysics Data System (ADS)

    Zhmud', A. A.

    1990-10-01

    A new multilevel optical element is proposed which is based on the Fizeau multibeam interferometer and a single-frequency wavelength-tunable semiconductor injection lazer. Possible applications of the optical element in optical data processors are discussed. As an example, a high-speed 17-bit analog-digital converter based on this element is considered.

  14. Optical system storage design with diffractive optical elements

    NASA Technical Reports Server (NTRS)

    Kostuk, Raymond K.; Haggans, Charles W.

    1993-01-01

    Optical data storage systems are gaining widespread acceptance due to their high areal density and the ability to remove the high capacity hard disk from the system. In magneto-optical read-write systems, a small rotation of the polarization state in the return signal from the MO media is the signal which must be sensed. A typical arrangement used for detecting these signals and correcting for errors in tracking and focusing on the disk is illustrated. The components required to achieve these functions are listed. The assembly and alignment of this complex system has a direct impact on cost, and also affects the size, weight, and corresponding data access rates. As a result, integrating these optical components and improving packaging techniques is an active area of research and development. Most designs of binary optic elements have been concerned with optimizing grating efficiency. However, rigorous coupled wave models for vector field diffraction from grating surfaces can be extended to determine the phase and polarization state of the diffracted field, and the design of polarization components. A typical grating geometry and the phase and polarization angles associated with the incident and diffracted fields are shown. In our current stage of work, we are examining system configurations which cascade several polarization functions on a single substrate. In this design, the beam returning from the MO disk illuminates a cascaded grating element which first couples light into the substrate, then introduces a quarter wave retardation, then a polarization rotation, and finally separates s- and p-polarized fields through a polarization beam splitter. The input coupler and polarization beam splitter are formed in volume gratings, and the two intermediate elements are zero-order elements.

  15. Design Rules For Holographic Optical Scanning Elements

    NASA Astrophysics Data System (ADS)

    Herzig, H. P.; Dandliker, R.

    1987-10-01

    An analytical method for the design of holographic optical elements (HOE) for focussing laser scanners with minimum aberrations and optimum scan line definition is reported. It can be shown analytically, using second order (paraxial) approximation, that a circular motion of the HOE cannot generate a straight line in space without astigmatism of the focal spot. Accepting a slightly curved scan line, the astigmatism can be compensated. Experimental results for HOE with a wavelength shift between recording and reconstruction are demonstrated. The required aspherical wavefronts for the recording are realized with the help of computer generated holograms (CGH).

  16. Virtual input device with diffractive optical element

    NASA Astrophysics Data System (ADS)

    Wu, Ching Chin; Chu, Chang Sheng

    2005-02-01

    As a portable device, such as PDA and cell phone, a small size build in virtual input device is more convenient for complex input demand. A few years ago, a creative idea called 'virtual keyboard' is announced, but up to now there's still no mass production method for this idea. In this paper we'll show the whole procedure of making a virtual keyboard. First of all is the HOE (Holographic Optical Element) design of keyboard image which yields a fan angle about 30 degrees, and then use the electron forming method to copy this pattern in high precision. And finally we can product this element by inject molding. With an adaptive lens design we can get a well correct keyboard image in distortion and a wilder fan angle about 70 degrees. With a batter alignment of HOE pattern lithography, we"re sure to get higher diffraction efficiency.

  17. Method of holding optical elements without deformation during their fabrication

    DOEpatents

    Hed, P. Paul

    1997-01-01

    An improved method for securing and removing an optical element to and from a blocking tool without causing deformation of the optical element. A lens tissue is placed on the top surface of the blocking tool. Dots of UV cement are applied to the lens tissue without any of the dots contacting each other. An optical element is placed on top of the blocking tool with the lens tissue sandwiched therebetween. The UV cement is then cured. After subsequent fabrication steps, the bonded blocking tool, lens tissue, and optical element are placed in a debonding solution to soften the UV cement. The optical element is then removed from the blocking tool.

  18. Methanogenesis from wastewater stimulated by addition of elemental manganese

    PubMed Central

    Qiao, Sen; Tian, Tian; Qi, Benyu; Zhou, Jiti

    2015-01-01

    This study presents a novel procedure for accelerating methanogenesis from wastewater by adding elemental manganese into the anaerobic digestion system. The results indicated that elemental manganese effectively enhanced both the methane yield and the production rate. Compared to the control test without elemental manganese, the total methane yield and production rate with 4 g/L manganese addition increased 3.4-fold (from 0.89 ± 0.03 to 2.99 ± 0.37 M/gVSS within 120 h) and 4.4-fold (from 6.2 ± 0.1 to 27.2 ± 2.2 mM/gVSS/h), respectively. Besides, more acetate consumption and less propionate generation were observed during the methanogenesis with manganese. Further studies demonstrated that the elemental manganese served as electron donors for the methanogenesis from carbon dioxide, and the final proportion of methane in the total generated gas with 4 g/L manganese addition reached 96.9%, which was 2.1-fold than that of the control (46.6%). PMID:26244609

  19. Additional security features for optically variable foils

    NASA Astrophysics Data System (ADS)

    Marshall, Allan C.; Russo, Frank

    1998-04-01

    For thousands of years, man has exploited the attraction and radiance of pure gold to adorn articles of great significance. Today, designers decorate packaging with metallic gold foils to maintain the prestige of luxury items such as perfumes, chocolates, wine and whisky, and to add visible appeal and value to wide range of products. However, today's products do not call for the hand beaten gold leaf of the Ancient Egyptians, instead a rapid production technology exists which makes use of accurately coated thin polymer films and vacuum deposited metallic layers. Stamping Foils Technology is highly versatile since several different layers may be combined into one product, each providing a different function. Not only can a foil bring visual appeal to an article, it can provide physical and chemical resistance properties and also protect an article from human forms of interference, such as counterfeiting, copying or tampering. Stamping foils have proved to be a highly effective vehicle for applying optical devices to items requiring this type of protection. Credit cards, bank notes, personal identification documents and more recently high value packaged items such as software and perfumes are protected by optically variable devices applied using stamping foil technology.

  20. Holographic Optical Elements as Scanning Lidar Telescopes

    NASA Technical Reports Server (NTRS)

    Schwemmer, Geary K.; Rallison, Richard D.; Wilkerson, Thomas D.; Guerra, David V.

    2005-01-01

    We have developed and investigated the use of holographic optical elements (HOEs) and holographic transmission gratings for scanning lidar telescopes. For example, rotating a flat HOE in its own plane with the focal spot on the rotation axis makes a very simple and compact conical scanning telescope. We developed and tested transmission and reflection HOEs for use at the first three harmonic wavelengths of Nd:YAG lasers. The diffraction efficiency, diffraction angle, focal length, focal spot size and optical losses were measured for several HOEs and holographic gratings, and found to be suitable for use as lidar receiver telescopes, and in many cases could also serve as the final collimating and beam steering optic for the laser transmitter. Two lidar systems based on this technology have been designed, built, and successfully tested in atmospheric science applications. This technology will enable future spaceborne lidar missions by significantly lowering the size, weight, power requirement and cost of a large aperture, narrow field of view scanning telescope.

  1. Athermalization and thermal characteristics of multilayer diffractive optical elements.

    PubMed

    Wang, Ju; Xue, Changxi

    2015-11-20

    A mathematical model to analyze the thermal characteristics of the multilayer diffractive optical elements (MLDOEs) is presented with consideration of the thermal characteristics for the refractive optical elements and single-layer diffractive optical elements. The analysis process of athermalization for MLDOEs by using the opto-thermal expansion coefficient of optical materials is given. Meanwhile, the microstructure heights of surface relief MLDOEs, the optical path difference, and the polychromatic integral diffraction efficiency with the ambient temperature changed are analyzed. The analysis results can be used to guide an athermalization design for the hybrid refractive-diffractive optical systems with MLDOEs.

  2. 2D optical beam splitter using diffractive optical elements (DOE)

    NASA Astrophysics Data System (ADS)

    Wen, Fung J.; Chung, Po S.

    2006-09-01

    A novel approach for optical beam distribution into a 2-dimensional (2-D) packaged fiber arrays using 2-D Dammann gratings is investigated. This paper focuses on the design and fabrication of the diffractive optical element (DOE) and investigates the coupling efficiencies of the beamlets into a packaged V-grooved 2x2 fibre array. We report for the first time experimental results of a 2-D optical signal distribution into a packaged 2x2 fibre array using Dammann grating. This grating may be applicable to the FTTH network as it can support sufficient channels with good output uniformity together with low polarization dependent loss (PDL) and acceptable insertion loss. Using an appropriate optimization algorithm (the steepest descent algorithm in this case), the optimum profile for the gratings can be calculated. The gratings are then fabricated on ITO glass using electron-beam lithography. The overall performance of the design shows an output uniformity of around 0.14 dB and an insertion loss of about 12.63 dB, including the DOE, focusing lens and the packaged fiber array.

  3. Determination of positions of optical elements of the human eye

    SciTech Connect

    Galetskii, S O; Cherezova, T Yu

    2009-02-28

    An original method for noninvasive determining the positions of elements of intraocular optics is proposed. The analytic dependence of the measurement error on the optical-scheme parameters and the restriction in distance from the element being measured are determined within the framework of the method proposed. It is shown that the method can be efficiently used for determining the position of elements in the classical Gullstrand eye model and personalised eye models. The positions of six optical surfaces of the Gullstrand eye model and four optical surfaces of the personalised eye model can be determined with an error of less than 0.25 mm. (human eye optics)

  4. Method of holding optical elements without deformation during their fabrication

    DOEpatents

    Hed, P.P.

    1997-04-29

    An improved method for securing and removing an optical element to and from a blocking tool without causing deformation of the optical element is disclosed. A lens tissue is placed on the top surface of the blocking tool. Dots of UV cement are applied to the lens tissue without any of the dots contacting each other. An optical element is placed on top of the blocking tool with the lens tissue sandwiched therebetween. The UV cement is then cured. After subsequent fabrication steps, the bonded blocking tool, lens tissue, and optical element are placed in a debonding solution to soften the UV cement. The optical element is then removed from the blocking tool. 16 figs.

  5. Method And Apparatus For Coupling Optical Elements To Optoelectronic Devices For Manufacturing Optical Transceiver Modules

    DOEpatents

    Anderson, Gene R.; Armendariz, Marcelino G.; Bryan, Robert P.; Carson, Richard F.; Chu, Dahwey; Duckett, III, Edwin B.; Giunta, Rachel Knudsen; Mitchell, Robert T.; McCormick, Frederick B.; Peterson, David W.; Rising, Merideth A.; Reber, Cathleen A.; Reysen, Bill H.

    2005-06-14

    A process is provided for aligning and connecting at least one optical fiber to at least one optoelectronic device so as to couple light between at least one optical fiber and at least one optoelectronic device. One embodiment of this process comprises the following steps: (1) holding at least one optical element close to at least one optoelectronic device, at least one optical element having at least a first end; (2) aligning at least one optical element with at least one optoelectronic device; (3) depositing a first non-opaque material on a first end of at least one optoelectronic device; and (4) bringing the first end of at least one optical element proximate to the first end of at least one optoelectronic device in such a manner that the first non-opaque material contacts the first end of at least one optoelectronic device and the first end of at least one optical element. The optical element may be an optical fiber, and the optoelectronic device may be a vertical cavity surface emitting laser. The first non-opaque material may be a UV optical adhesive that provides an optical path and mechanical stability. In another embodiment of the alignment process, the first end of at least one optical element is brought proximate to the first end of at least one optoelectronic device in such a manner that an interstitial space exists between the first end of at least one optoelectronic device and the first end of at least one optical element.

  6. Photoresist surface roughness characterization in additive lithography processes for fabrication of phase-only optical vortices

    NASA Astrophysics Data System (ADS)

    Poutous, Menelaos K.; Hosseinimakarem, Zahra; Johnson, Eric G.

    2012-10-01

    Roughness on the surface of phase-only micro-optical elements limits their performance. An optical vortex phase element was fabricated, using additive lithography, with an optimized process to achieve minimal surface roughness. Shipley S1827 photoresist was used in order to obtain the appropriate additive lithography dynamic range for the desired phase profile. We investigated the effects of both postapplied and postexposure baking processes, bias exposure dose, as well as the effects of surfactant in the developer. We found the resist surface roughness to be a function of both the temperature and the time of the postapplication baking cycles, as well as the developer surfactant content. Based on our findings, an empirical correlation model was constructed to relate the process parameters with surface roughness measured quantities. The maximum roughness of the optical surface, for the optimized process, was reduced to 40 percent of the value for the unoptimized process and the additive lithography useful exposure range was increased by 10 percent.

  7. Photoresist roughness characterization in additive lithography processes for the fabrication of phase-only optical vortices

    NASA Astrophysics Data System (ADS)

    Hosseinimakarem, Zahra; Poutous, Menelaos K.; Johnson, Eric G.

    2012-03-01

    The roughness on the surface of phase-only micro-optical elements can limit their performance. An optical vortex phase element was fabricated by using additive lithography with an optimized process to have minimal surface roughness. Thick photoresist was used in order to obtain the appropriate dynamic range for the desired phase profile. We investigated the effects of both post applied and post exposure baking processes, as well as the effects of surfactant in the developer. We found the resist surface roughness to be a function of both the temperature and the time of the respective bakes, as well as the developer surfactant content.

  8. Diffractive optical elements for transformation of modes in lasers

    DOEpatents

    Sridharan, Arun K.; Pax, Paul H.; Heebner, John E.; Drachenberg, Derrek R.; Armstrong, James P.; Dawson, Jay W.

    2015-09-01

    Spatial mode conversion modules are described, with the capability of efficiently transforming a given optical beam profile, at one plane in space into another well-defined optical beam profile at a different plane in space, whose detailed spatial features and symmetry properties can, in general, differ significantly. The modules are comprised of passive, high-efficiency, low-loss diffractive optical elements, combined with Fourier transform optics. Design rules are described that employ phase retrieval techniques and associated algorithms to determine the necessary profiles of the diffractive optical components. System augmentations are described that utilize real-time adaptive optical techniques for enhanced performance as well as power scaling.

  9. Diffractive optical elements for transformation of modes in lasers

    DOEpatents

    Sridharan, Arun K; Pax, Paul H; Heebner, John E; Drachenberg, Derrek R.; Armstrong, James P.; Dawson, Jay W.

    2016-06-21

    Spatial mode conversion modules are described, with the capability of efficiently transforming a given optical beam profile, at one plane in space into another well-defined optical beam profile at a different plane in space, whose detailed spatial features and symmetry properties can, in general, differ significantly. The modules are comprised of passive, high-efficiency, low-loss diffractive optical elements, combined with Fourier transform optics. Design rules are described that employ phase retrieval techniques and associated algorithms to determine the necessary profiles of the diffractive optical components. System augmentations are described that utilize real-time adaptive optical techniques for enhanced performance as well as power scaling.

  10. Analogy between generalized Coddington equations and thin optical element approximation.

    PubMed

    Golub, Michael A

    2009-05-01

    Local wavefront curvature transformations at an arbitrarily shaped optical surface are commonly determined by generalized Coddington equations that are developed here via a local thin optical element approximation. Eikonal distributions of the incident and refracted beams are calculated and related by an eikonal transfer function of a local thin optical element located in close proximity to a given point at a tangent plane of an optical surface. Main coefficients and terms involved in the generalized Coddington equations are derived and explained as a local nonparaxial generalization for the customary paraxial wavefront transformations.

  11. Validity of ray trace based performance predictions of optical systems with diffractive optical elements (DOE)

    NASA Astrophysics Data System (ADS)

    Seesselberg, Markus; Kleemann, Bernd H.; Ruoff, Johannes

    2016-09-01

    Color aberrations in broadband imaging optics can be effectively corrected for by use of diffractive optical elements (DOE) such as kinoforms. Typically, the DOE groove width increases with wavelength range and is in the range of several ten to several hundreds of micrometers. Since the footprint diameter of a light bundle originating from a single object point at the diffractive surface is often in the range of millimeters, the number of grooves crossed by this light bundle can be small. In addition, the groove width varies and the grooves are curved. For DOE optimization and prediction of optical performance, optical design software is widely used being based on the ray trace formula, i. e. the law of refraction including DOEs. This ray trace formula relies on two assumptions. First, the footprint diameter of a light beam at the diffractive surface is assumed to be large compared to the groove width. Second, the local grating approximation is used saying that at the footprint area the groove width is constant and the grooves are straight lines. In realistic optical systems, these assumptions are often violated. Thus, the reliability of optical performance predictions such as MTF is in question. In the present paper, the authors re-examine the limits of the ray trace equation. The effect of a finite footprint diameter at the diffractive surface is investigated as well as variations of the groove width. Also, the Fraunhofer diffraction pattern of a light bundle after crossing a grating with a finite number of grooves is calculated.

  12. Implementations of adaptive associative optical computing elements

    NASA Astrophysics Data System (ADS)

    Fisher, Arthur D.; Lee, John N.; Fukuda, Robert C.

    1986-01-01

    The present optical implementations for heteroassociative memory modules, which are capable of real time adaptive learning, are pertinent to the eventual construction of large, multimodule associative/neural network architectures that can consider problems in the acquisition, transformation, matching/recognition, and manipulation of large amounts of data in parallel. These modules offer such performance features as convergence to the least-squares-optimum pseudoinverse association, accumulative and gated learning, forgetfulness of unused associations, resistance to dynamic-range saturation, and compensation of optical system aberrations. Optics uniquely furnish the massive parallel interconnection paths required to cascade and interconnect a number of modules to form the more sophisticated multiple module architectures.

  13. Analysis of offset error for segmented micro-structure optical element based on optical diffraction theory

    NASA Astrophysics Data System (ADS)

    Su, Jinyan; Wu, Shibin; Yang, Wei; Wang, Lihua

    2016-10-01

    Micro-structure optical elements are gradually applied in modern optical system due to their characters such as light weight, replicating easily, high diffraction efficiency and many design variables. Fresnel lens is a typical micro-structure optical element. So in this paper we take Fresnel lens as base of research. Analytic solution to the Point Spread Function (PSF) of the segmented Fresnel lens is derived based on the theory of optical diffraction, and the mathematical simulation model is established. Then we take segmented Fresnel lens with 5 pieces of sub-mirror as an example. In order to analyze the influence of different offset errors on the system's far-field image quality, we obtain the analytic solution to PSF of the system under the condition of different offset errors by using Fourier-transform. The result shows the translation error along XYZ axis and tilt error around XY axis will introduce phase errors which affect the imaging quality of system. The translation errors along XYZ axis constitute linear relationship with corresponding phase errors and the tilt errors around XY axis constitute trigonometric function relationship with corresponding phase errors. In addition, the standard deviations of translation errors along XY axis constitute quadratic nonlinear relationship with system's Strehl ratio. Finally, the tolerances of different offset errors are obtained according to Strehl Criteria.

  14. Effects of extreme pressure additive chemistry on rolling element bearing surface durability

    SciTech Connect

    Evans, Ryan D.; Nixon, H. P.; Darragh, Craig V.; Howe, Jane Y; Coffey, Dorothy W

    2007-01-01

    Lubricant additives have been known to affect rolling element bearing surface durability for many years. Tapered roller bearings were used in fatigue testing of lubricants formulated with gear oil type additive systems. These systems have sulfur- and phosphoruscontaining compounds used for gear protection as well as bearing lubrication. Several variations of a commercially available base additive formulation were tested having modified sulfur components. The variations represent a range of ''active'' extreme pressure (EP) chemistries. The bearing fatigue test results were compared with respect to EP formulation and test conditions. Inner ring near-surface material in selected test bearings was evaluated on two scales: the micrometer scale using optical metallography and the nanometer scale using transmission electron microscopy (TEM). Focused-ion beam (FIB) techniques were used for TEM specimen preparation. Imaging and chemical analysis of the bearing samples revealed near-surface material and tribofilm characteristics. These results are discussed with respect to the relative fatigue lives.

  15. System and method for reproducibly mounting an optical element

    DOEpatents

    Eisenbies, Stephen; Haney, Steven

    2005-05-31

    The present invention provides a two-piece apparatus for holding and aligning the MEMS deformable mirror. The two-piece apparatus comprises a holding plate for fixedly holding an adaptive optics element in an overall optical system and a base spatially fixed with respect to the optical system and adapted for mounting and containing the holding plate. The invention further relates to a means for configuring the holding plate through adjustments to each of a number of off-set pads touching each of three orthogonal plane surfaces on the base, wherein through the adjustments the orientation of the holding plate, and the adaptive optics element attached thereto, can be aligned with respect to the optical system with six degrees of freedom when aligning the plane surface of the optical element. The mounting system thus described also enables an operator to repeatedly remove and restore the adaptive element in the optical system without the need to realign the system once that element has been aligned.

  16. Addition of higher order plate and shell elements into NASTRAN computer program

    NASA Technical Reports Server (NTRS)

    Narayanaswami, R.; Goglia, G. L.

    1976-01-01

    Two higher order plate elements, the linear strain triangular membrane element and the quintic bending element, along with a shallow shell element, suitable for inclusion into the NASTRAN (NASA Structural Analysis) program are described. Additions to the NASTRAN Theoretical Manual, Users' Manual, Programmers' Manual and the NASTRAN Demonstration Problem Manual, for inclusion of these elements into the NASTRAN program are also presented.

  17. Design of nanophotonic elements with transformation optics

    NASA Astrophysics Data System (ADS)

    Ginis, Vincent; Tassin, Philippe; Danckaert, Jan; Soukoulis, Costas M.; Veretennicoff, Irina

    2012-10-01

    In this contribution we show that the fundamental diffraction limit of optical cavities can be overcome using a transformation-optical approach. Transformation optics has recently provided a new method for the design of devices to control electromagnetic fields, based on the analogy between the macroscopic Maxwell's equations in complex dielectrics and the free-space Maxwell's equations in a curved coordinate system. It offers an elegant approach to exploit the full potential of metamaterials. We show how transformation optics can be used to achieve the opposite e ect of an invisibility cloak; instead of prohibiting the electromagnetic waves from entering a predefi ned region, we encapsulate the light waves within such a finite region. This allows us to design cavities with extraordinary properties. We have been able to demonstrate theoretically the existence of eigenmodes whose wavelength is much larger than the characteristic dimensions of the device. Furthermore, our cavities avoid the bending losses observed in traditional microcavities, so the quality factor is only limited by the intrinsic absorption of the materials. Finally, we also demonstrate how the combination of radial and angular transformations allows developing cavities without bending losses using right-handed material parameters only.1, 2

  18. Electrostatic dust protection for optical elements

    NASA Astrophysics Data System (ADS)

    Hoenig, S. A.

    1982-02-01

    The application of electrostatic technology to the protection of optical components in earth-mounted and satellite orbital systems has been investigated. Theory and experiment indicate it is quite practical to prevent dust deposition in an earth environment. A mathematical analysis indicates even better results should be obtained in an orbital vehicle.

  19. Bifunctional air electrodes containing elemental iron powder charging additive

    DOEpatents

    Liu, Chia-tsun; Demczyk, Brian G.; Gongaware, Paul R.

    1982-01-01

    A bifunctional air electrode for use in electrochemical energy cells is made, comprising a hydrophilic layer and a hydrophobic layer, where the hydrophilic layer essentially comprises a hydrophilic composite which includes: (i) carbon; (ii) elemental iron particles having a particle size of between about 25 microns and about 700 microns diameter; (iii) an oxygen evolution material; (iv) a nonwetting agent; and (v) a catalyst, where at least one current collector is formed into said composite.

  20. Diffractive micro-optical element with nonpoint response

    NASA Astrophysics Data System (ADS)

    Soifer, Victor A.; Golub, Michael A.

    1993-01-01

    Common-use diffractive lenses have microrelief zones in the form of simple rings that provide only an optical power but do not contain any image information. They have a point-image response under point-source illumination. We must use a more complicated non-point response to focus a light beam into different light marks, letter-type images as well as for optical pattern recognition. The current presentation describes computer generation of diffractive micro- optical elements with complicated curvilinear zones of a regular piecewise-smooth structure and grey-level or staircase phase microrelief. The manufacture of non-point response elements uses the steps of phase-transfer calculation and orthogonal-scan masks generation or lithographic glass etching. Ray-tracing method is shown to be applicable in this task. Several working samples of focusing optical elements generated by computer and photolithography are presented. Using the experimental results we discuss here such applications as laser branding.

  1. Fiber optic interferometer as a security element

    NASA Astrophysics Data System (ADS)

    Nedoma, Jan; Zboril, Ondrej; Fajkus, Marcel; Cubik, Jakub; Zavodny, Petr; Novak, Martin; Bednarek, Lukas; Martinek, Radek; Vasinek, Vladimir

    2016-04-01

    Interferometric sensors can be categorized as highly sensitive and precise devices with series inconsiderable benefits from the possibility of using standard telecommunication fibers. They can be measured even small changes in the deformation of shapes in time, changes in temperature, pressure, voltage, vibration, electric field, etc. The basic idea, which is described in this article is the usage of the interferometer as a security and monitoring component, which offers a solution for securing of closed spaces, especially before unwanted entries. Its primary task is to detect intrusions - disrupting the integrity of the transparent window area due to vibration response. The base of the solution is a Mach-Zehnder interferometer, which consists of two arms in the power distribution ratio of 1:1, consisting of the SM optical fiber excited by a DFB laser. The interferometer is working on the wavelength of 1550 nm. The resulting signal is registered as a result of interference of optical beams from the reference and sensor arm. Realized measuring scheme was terminated optical receiver comprising PbSe detector. Below described experimental measurements have shown that implemented interferometer has a sufficient value of the signal to noise ratio (SNR) and is able to detect very weak signals in a wide frequency range from tens of Hz to kHz units. The signal was processed by applications developed for the amplitude-frequency spectrum. Evaluated was the maximum amplitude of the signal and compared to the noise. The results were verified by retesting the assembled prototype.

  2. Sighting optics including an optical element having a first focal length and a second focal length

    DOEpatents

    Crandall, David Lynn

    2011-08-01

    One embodiment of sighting optics according to the teachings provided herein may include a front sight and a rear sight positioned in spaced-apart relation. The rear sight includes an optical element having a first focal length and a second focal length. The first focal length is selected so that it is about equal to a distance separating the optical element and the front sight and the second focal length is selected so that it is about equal to a target distance. The optical element thus brings into simultaneous focus, for a user, images of the front sight and the target.

  3. Diffraction efficiency analysis for multi-level diffractive optical elements

    SciTech Connect

    Erteza, I.A.

    1995-11-01

    Passive optical components can be broken down into two main groups: Refractive elements and diffractive elements. With recent advances in manufacturing technologies, diffractive optical elements are becoming increasingly more prevalent in optical systems. It is therefore important to be able to understand and model the behavior of these elements. In this report, we present a thorough analysis of a completely general diffractive optical element (DOE). The main goal of the analysis is to understand the diffraction efficiency and power distribution of the various modes affected by the DOE. This is critical to understanding cross talk and power issues when these elements are used in actual systems. As mentioned, the model is based on a completely general scenario for a DOE. This allows the user to specify the details to model a wide variety of diffractive elements. The analysis is implemented straightforwardly in Mathematica. This report includes the development of the analysis, the Mathematica implementation of the model and several examples using the Mathematical analysis tool. It is intended that this tool be a building block for more specialized analyses.

  4. Dual Ion Beam Deposition Of Diamond Films On Optical Elements

    NASA Astrophysics Data System (ADS)

    Deutchman, Arnold H.; Partyka, Robert J.; Lewis, J. C.

    1990-01-01

    Diamond film deposition processes are of great interest because of their potential use for the formation of both protective as well as anti-reflective coatings on the surfaces of optical elements. Conventional plasma-assisted chemical vapor deposition diamond coating processes are not ideal for use on optical components because of the high processing temperatures required, and difficulties faced in nucleating films on most optical substrate materials. A unique dual ion beam deposition technique has been developed which now makes possible deposition of diamond films on a wide variety of optical elements. The new DIOND process operates at temperatures below 150 aegrees Farenheit, and has been used to nucleate and grow both diamondlike carbon and diamond films on a wide variety of optical :taterials including borosilicate glass, quartz glass, plastic, ZnS, ZnSe, Si, and Ge.

  5. Micro-optical elements for optical wireless applications

    NASA Astrophysics Data System (ADS)

    Jin, Xian; Guerrero, Daniel; Klukas, Richard; Holzman, Jonathan F.

    2013-09-01

    Customized high-contact-angle microlenses are presented for optical wireless communication (OWC) and optical wireless location (OWL) applications. These microlenses are fabricated by way of an electro-dispensing technique to establish wide field-of-views (FOVs). Each microlens is formed from dispensed UV-curable polymer with pressurecontrol defining the microlens volume and a voltage on the metal needle tip defining the microlens shape (by way of electrowetting). UV curing is then applied. Microlenses with FOVs up to 90° are fabricated for high-density integration above a CMOS imaging sensor for wide-FOV operation in emerging OWC and OWL applications. Both theoretical raytracing analyses and experimental imaging results are presented with good agreement.

  6. 41 CFR 60-2.17 - Additional required elements of affirmative action programs.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... elements of affirmative action programs. 60-2.17 Section 60-2.17 Public Contracts and Property Management... Action Programs § 60-2.17 Additional required elements of affirmative action programs. In addition to the elements required by § 60-2.10 through § 60-2.16, an acceptable affirmative action program must include...

  7. Spectral diffraction efficiency characterization of broadband diffractive optical elements.

    SciTech Connect

    Choi, Junoh; Cruz-Cabrera, Alvaro Augusto; Tanbakuchi, Anthony

    2013-03-01

    Diffractive optical elements, with their thin profile and unique dispersion properties, have been studied and utilized in a number of optical systems, often yielding smaller and lighter systems. Despite the interest in and study of diffractive elements, the application has been limited to narrow spectral bands. This is due to the etch depths, which are optimized for optical path differences of only a single wavelength, consequently leading to rapid decline in efficiency as the working wavelength shifts away from the design wavelength. Various broadband diffractive design methodologies have recently been developed that improve spectral diffraction efficiency and expand the working bandwidth of diffractive elements. We have developed diffraction efficiency models and utilized the models to design, fabricate, and test two such extended bandwidth diffractive designs.

  8. Comparative study of two CPV optical concentrators, using a Fresnel lens as primary optical element

    NASA Astrophysics Data System (ADS)

    El Himer, S.; El-Yahyaoui, S.; Mechaqrane, A.; Ahaitouf, A.

    2017-03-01

    In this work, the performances of two optimized reflective secondary optics elements a CPC (Compound Parabolic Concentrator) and a Cone for use in a CPV concentrator system are studied using ray-tracing simulation for the same primary optical element: a Fresnel lens. These optical elements are compared in terms of concentration, acceptance angle, exit angle and output light distribution. Our results show that the power distribution at the end of the concentrator is more uniform in the case of the cone. The optical efficiency is higher when the secondary element is placed at a distance f + \\frac{\\text{R}}{{\\tan \\text{θ }}} with f the focal length; R the input radius of the secondary optical element and θ the acceptance angle of the secondary optical element. Also, we found that the length and the input radius of each optical element decrease when the Fresnel lens diameter increases but the input radius of the CPC stills the larger. Finally, our calculation show that the CPC is longer than the cone while the Fresnel lens diameter is less than 200 mm and beyond this value both the cone and the CPC mostly present the same length.

  9. Development of multiple-surface optical elements for road lighting.

    PubMed

    Kravchenko, Sergey V; Byzov, Egor V; Moiseev, Mikhail A; Doskolovich, Leonid L

    2017-02-20

    The development of LED secondary optics for road illumination is quite a challenging problem. Optical elements developed for this kind of application should have maximal efficiency, provide high luminance and illuminance uniformity, and meet many other specific requirements. Here, we demonstrate that the usage of the supporting quadric method modification enables generating free-form optical solution satisfying all these requirements perfectly. As an example, two optical elements for different roadway types are computed, manufactured by injection molding, and then measured in a photometry bench. Experimental data demonstrate that the obtained light distributions meet ME1 class requirements of EN 13201 standard. The obtained directivity patterns are universal and provide high performance with different configurations of luminaires' arrangement: the ratio of pole altitude to distance can vary from 2.5 up to 3.6.

  10. Photodeposited diffractive optical elements of computer generated masks

    NASA Astrophysics Data System (ADS)

    Mirchin, N.; Peled, A.; Baal-Zedaka, I.; Margolin, R.; Zagon, M.; Lapsker, I.; Verdyan, A.; Azoulay, J.

    2005-07-01

    Diffractive optical elements (DOE) were synthesized on plastic substrates using the photodeposition (PD) technique by depositing amorphous selenium (a-Se) films with argon lasers and UV spectra light. The thin films were deposited typically onto polymethylmethacrylate (PMMA) substrates at room temperature. Scanned beam and contact mask modes were employed using computer-designed DOE lenses. Optical and electron micrographs characterize the surface details. The films were typically 200 nm thick.

  11. Single Photon Holographic Qudit Elements for Linear Optical Quantum Computing

    DTIC Science & Technology

    2011-05-01

    in optical volume holography and designed and simulated practical single-photon, single-optical elements for qudit MUB-state quantum in- formation...Independent of the representation we use, the MUB states will ordinarily be modulated in both amplitude and phase. Recently a practical method has been...quantum computing with qudits (d ≥ 3) has been an efficient and practical quantum state sorter for photons whose complex fields are modulated in both

  12. Adaptive beam shaping by controlled thermal lensing in optical elements.

    PubMed

    Arain, Muzammil A; Quetschke, Volker; Gleason, Joseph; Williams, Luke F; Rakhmanov, Malik; Lee, Jinho; Cruz, Rachel J; Mueller, Guido; Tanner, D B; Reitze, David H

    2007-04-20

    We describe an adaptive optical system for use as a tunable focusing element. The system provides adaptive beam shaping via controlled thermal lensing in the optical elements. The system is agile, remotely controllable, touch free, and vacuum compatible; it offers a wide dynamic range, aberration-free focal length tuning, and can provide both positive and negative lensing effects. Focusing is obtained through dynamic heating of an optical element by an external pump beam. The system is especially suitable for use in interferometric gravitational wave interferometers employing high laser power, allowing for in situ control of the laser modal properties and compensation for thermal lensing of the primary laser. Using CO(2) laser heating of fused-silica substrates, we demonstrate a focal length variable from infinity to 4.0 m, with a slope of 0.082 diopter/W of absorbed heat. For on-axis operation, no higher-order modes are introduced by the adaptive optical element. Theoretical modeling of the induced optical path change and predicted thermal lens agrees well with measurement.

  13. Fiber-optic backreflectance method for determining the effective focal lengths of optical elements.

    PubMed

    Ilev, I; Uttamchandani, D; Culshaw, B

    1996-02-01

    An alternative and simple fiber-optic backreflectance method for indirectly determining the effective focal lengths of optical elements by the spatial location of three specific points (the focal point and two object points) is presented. The basic optical element of the method is the single-mode optical fiber. It serves simultaneously as a point light source, an object for projecting, and a point receiver that is highly sensitive to spatial displacements for focused backreflectance laser emission. The method provides high accuracy for both locating the spatial points (1 µm) and determining the effective focal length (less than 0.5%).

  14. Additive Manufacturing of Functional Elements on Sheet Metal

    NASA Astrophysics Data System (ADS)

    Schaub, Adam; Ahuja, Bhrigu; Butzhammer, Lorenz; Osterziel, Johannes; Schmidt, Michael; Merklein, Marion

    Laser Beam Melting (LBM) process with its advantages of high design flexibility and free form manufacturing methodology is often applied limitedly due to its low productivity and unsuitability for mass production compared to conventional manufacturing processes. In order to overcome these limitations, a hybrid manufacturing methodology is developed combining the additive manufacturing process of laser beam melting with sheet forming processes. With an interest towards aerospace and medical industry, the material in focus is Ti-6Al-4V. Although Ti-6Al-4V is a commercially established material and its application for LBM process has been extensively investigated, the combination of LBM of Ti-6Al-4V with sheet metal still needs to be researched. Process dynamics such as high temperature gradients and thermally induced stresses lead to complex stress states at the interaction zone between the sheet and LBM structure. Within the presented paper mechanical characterization of hybrid parts will be performed by shear testing. The association of shear strength with process parameters is further investigated by analyzing the internal structure of the hybrid geometry at varying energy inputs during the LBM process. In order to compare the hybrid manufacturing methodology with conventional fabrication, the conventional methodologies subtractive machining and state of the art Laser Beam Melting is evaluated within this work. These processes will be analyzed for their mechanical characteristics and productivity by determining the build time and raw material consumption for each case. The paper is concluded by presenting the characteristics of the hybrid manufacturing methodology compared to alternative manufacturing technologies.

  15. Programmable diffractive optical elements for extending the depth of focus in ophthalmic optics

    NASA Astrophysics Data System (ADS)

    Romero, Lenny A.; Millán, María. S.; Jaroszewicz, Zbigniew; Kołodziejczyk, Andrzej

    2015-01-01

    The depth of focus (DOF) defines the axial range of high lateral resolution in the image space for object position. Optical devices with a traditional lens system typically have a limited DOF. However, there are applications such as in ophthalmology, which require a large DOF in comparison to a traditional optical system, this is commonly known as extended DOF (EDOF). In this paper we explore Programmable Diffractive Optical Elements (PDOEs), with EDOF, as an alternative solution to visual impairments, especially presbyopia. These DOEs were written onto a reflective liquid cystal on silicon (LCoS) spatial light modulator (SLM). Several designs of the elements are analyzed: the Forward Logarithmic Axicon (FLAX), the Axilens (AXL), the Light sword Optical Element (LSOE), the Peacock Eye Optical Element (PE) and Double Peacock Eye Optical Element (DPE). These elements focus an incident plane wave into a segment of the optical axis. The performances of the PDOEs are compared with those of multifocal lenses. In all cases, we obtained the point spread function and the image of an extended object. The results are presented and discussed.

  16. Analog of Optical Elements for Sound Waves in Air

    ERIC Educational Resources Information Center

    Gluck, Paul; Perkalskis, Benjamin

    2009-01-01

    Optical elements manipulate light waves. They may be used to focus the light or to change the phase, the polarization, the direction, or the intensity of light. Many of these functions are often demonstrated with microwaves, since the devices normally available in teaching laboratories produce wavelengths in the centimeter range and are therefore…

  17. Conformal optical elements for correcting wavefront distortions in YAG : Nd{sup 3+} active elements

    SciTech Connect

    Korolkov, V P; Nasyrov, R K; Poleshchuk, A G; Arapov, Yu D; Ivanov, A F

    2013-02-28

    Correction of the wavefront is studied for the light beam passing wide-aperture YAG : Nd3+ single-crystal rods, which are used as active elements in high-power solid-state lasers. A nonideal character of the crystal structure is responsible for the deformation of the wavefront of passing radiation. By using the halftone technology we have developed conformal aberration correctors capable of compensating rod nonuniformities and reducing the laser radiation divergence by an order of magnitude. The results obtained make it possible to employ optically nonuniform active elements in laser constructions. (laser optics 2012)

  18. Diffractive Optical Element design for lateral spectrum splitting photovoltaics

    NASA Astrophysics Data System (ADS)

    Vorndran, Shelby D.

    In this work, two distinct types of Diffractive Optical Elements (DOEs) are designed to laterally distribute the solar spectrum across multiple photovoltaic (PV) cells. Each PV cell receives a spectral band near its bandgap energy to maximize overall solar-to-electric conversion efficiency of the system. The first DOE is an off-axis volume holographic lens. Design parameters include lateral grating period and slant angle, index modulation, film thickness, and control of swelling and index modulation attenuation in the film development process. Diffraction efficiency across the holographic lens is simulated using Rigorous Coupled Wave Analysis (RCWA). A full system model is created, and non-sequential ray tracing is performed. Performance is evaluated under AM 1.5 conditions and annual insolation in Tucson, AZ, and Seattle, WA. A proof-of-concept off-axis holographic lens is fabricated and its performance is measured to confirm the optical properties of this system. The second DOE is an algorithmically-designed freeform surface relief structure. The Gerchberg-Saxton design algorithm is expanded to consider multiple wavelengths, resulting in a Broadband Gerchberg-Saxton (BGS) algorithm. All design variables are evaluated in a parametric study of the algorithm. Several DOE designs are proposed for spectrum splitting, and two of these designs are fabricated and measured. Additional considerations, such as finite sampling of the discrete Fourier transform, fabrication error, and solar divergence are addressed. The dissertation will conclude with a summary of spectrum splitting performance of all proposed DOEs, as well as a comparison to ideal spectrum splitting performance and discussion of areas for improvement and future work.

  19. Design approach for systems with toroidal optical elements featuring a generalized Scheimpflug condition

    NASA Astrophysics Data System (ADS)

    Ott, Peter; Eckstein, Johannes; Gao, Jun

    2006-01-01

    Toroidal elements are special aspheric elements with a missing axial section. Such elements consist of several refractive and/or reflective optical surfaces which are generally tilted with respect to a base ray. This base ray replaces the optical axis in ordinary centered systems. Toroidal elements can be efficiently applied e.g. in LED illumination systems or in optical metrology systems. For these elements there is a lack of design principles, only very few approaches like the Coddington equations are known. In this paper an efficient method is presented that facilitates the design when the requirement or knowledge of the orientation of the image plane is necessary, i.e. where a generalized Scheimpflug condition is needed. In more general terms, the method results in imaging properties of second order expansion, but the method itself is linear. Therefore, the complexity of the design process is considerably reduced. Additionally it is shown how the individual surfaces of the toroidal element can be easily aspherized for sharp imaging omitting tedious optimization. The strength of the design method is demonstrated for a novel application where a complex toroidal element is required for rotationally symmetric triangulation integrated in a vision systems and for a high aperture illumination element based on TIR for LEDs.

  20. Polarizing optical interferometer having a dual use optical element

    DOEpatents

    Kotidis, Petros A.; Woodroffe, Jaime A.; Rostler, Peter S.

    1995-01-01

    A system for non-destructively measuring an object and controlling industrial processes in response to the measurement is disclosed in which an impulse laser generates a plurality of sound waves over timed increments in an object. A polarizing interferometer is used to measure surface movement of the object caused by the sound waves and sensed by phase shifts in the signal beam. A photon multiplier senses the phase shift and develops an electrical signal. A signal conditioning arrangement modifies the electrical signals to generate an average signal correlated to the sound waves which in turn is correlated to a physical or metallurgical property of the object, such as temperature, which property may then be used to control the process. External, random vibrations of the workpiece are utilized to develop discernible signals which can be sensed in the interferometer by only one photon multiplier. In addition the interferometer includes an arrangement for optimizing its sensitivity so that movement attributed to various waves can be detected in opaque objects. The interferometer also includes a mechanism for sensing objects with rough surfaces which produce speckle light patterns. Finally the interferometer per se, with the addition of a second photon multiplier is capable of accurately recording beam length distance differences with only one reading.

  1. Polarizing optical interferometer having a dual use optical element

    DOEpatents

    Kotidis, P.A.; Woodroffe, J.A.; Rostler, P.S.

    1995-04-04

    A system for nondestructively measuring an object and controlling industrial processes in response to the measurement is disclosed in which an impulse laser generates a plurality of sound waves over timed increments in an object. A polarizing interferometer is used to measure surface movement of the object caused by the sound waves and sensed by phase shifts in the signal beam. A photon multiplier senses the phase shift and develops an electrical signal. A signal conditioning arrangement modifies the electrical signals to generate an average signal correlated to the sound waves which in turn is correlated to a physical or metallurgical property of the object, such as temperature, which property may then be used to control the process. External, random vibrations of the workpiece are utilized to develop discernible signals which can be sensed in the interferometer by only one photon multiplier. In addition the interferometer includes an arrangement for optimizing its sensitivity so that movement attributed to various waves can be detected in opaque objects. The interferometer also includes a mechanism for sensing objects with rough surfaces which produce speckle light patterns. Finally the interferometer per se, with the addition of a second photon multiplier is capable of accurately recording beam length distance differences with only one reading. 38 figures.

  2. Additive coloring of CaF2 optical ceramic

    NASA Astrophysics Data System (ADS)

    Shcheulin, A. S.; Ryskin, A. I.; Angervaks, A. E.; Fedorov, P. P.; Osiko, V. V.; Demidenko, A. A.; Garibin, E. A.; Smirnov, A. N.; Dukel'skii, K. V.; Mironov, I. A.

    2011-04-01

    The specificity of additive coloring of CaF2 optical ceramic (formation of color centers in it and photothermochemical transformation of these centers in colored ceramic samples) has been considered. Under the same coloring conditions, this process occurs more slowly in ceramics rather than in crystals; at the same time, the limiting concentration of color centers that can be introduced into ceramics is much higher. The photothermochemical transformations of color centers in crystals and ceramics, which occur under illumination at different wavelengths and upon heating, have been studied. The specific features of introduction of color centers into ceramic and their transformation under illumination and heating are likely to be related to the mass twinning of ceramic grains.

  3. Reporting of NSC Additional (A2) Data Elements. Updated July 29, 2014

    ERIC Educational Resources Information Center

    National Student Clearinghouse, 2014

    2014-01-01

    Since the 2008-09 academic year, the National Student Clearinghouse has provided its participating institutions with the option to include 13 additional data elements in their enrollment submissions. These additional data elements help make Clearinghouse data more comprehensive and enable StudentTracker? participants to utilize a more robust data…

  4. Finite element analysis to evaluate optical mirror deformations

    NASA Astrophysics Data System (ADS)

    Izazaga-Pérez, R.; Aguirre-Aguirre, D.; Villalobos-Mendoza, B.

    2015-10-01

    In this work we describe the use of Finite Element Analysis software to simulate the deformations of an optical mirror. We use Finite Element Method software as a tool to simulate the mirror deformations assuming that it is a thin plate that can be mechanically tensed or compressed; the Finite Element Analysis give us information about the displacements of the mirror from an initial position and the tensions that remains in the surface. The information obtained by means of Finite Element Analysis can be easily exported to a coordinate system and processed in a simulation environment. Finally, a ray-tracing subroutine is used in the obtained data giving us information in terms of aberration coefficients. We present some results of the simulations describing the followed procedure.

  5. Optical Multiplications With Single Element 2-D Acousto-Optic Laser Beam Deflector

    NASA Astrophysics Data System (ADS)

    Soos, Jolanta I.; Leepa, Douglas C.; Rosemeier, Ronald G.

    1989-05-01

    With the current need for developing very fast computers in comparison to conventional digital chip based systems, the future for optical based signal processing is very bright. Attention has turned to a different application of optics utilizing mathematical operations, in which case operations are numerical, sometimes discrete, and often algebraic in nature. Interest has been so vigorous that many view it as a small revolution in optics, whereby optical signal processing is beginning to encompass what is frequently described as optical computing. The term is fully intended to imply a close comparison with the operations performed by scientific digital canputers. This paper will describe the applications of single element 2-D acousto-optic deflectors for optical multiplication systems.

  6. Holographic optical elements for the extreme-ultravioletregime

    SciTech Connect

    Naulleau, Patrick P.; Salmassi, Farhad; Gullikson, Eric M.; Anderson, Erik H.

    2006-08-14

    As the development of extreme ultraviolet (EUV) lithography progresses, interest grows in the extension of traditional optical components to the EUV regime. The strong absorption of EUV by most materials and its extremely short wavelength, however, makes it very difficult to implement many components that are commonplace in the longer wavelength regimes. One such component is the diffractive optical element used, for example, in illumination systems to efficiently generate modified pupil fills. Here we demonstrate the fabrication and characterization of EUV binary phase-only computer-generated holograms allowing arbitrary far-field diffraction patterns to be generated.

  7. Multifunctional diffractive optical elements for the generation of higher order Bessel-like-beams

    NASA Astrophysics Data System (ADS)

    Vijayakumar, A.; Bhattacharya, Shanti

    2015-01-01

    Higher Order Bessel Beams (HOBBs) have many useful applications in optical trapping experiments. The generation of HOBBs is achieved by illuminating an axicon by a Laguerre-Gaussian beam generated by a spiral phase plate. It can also be generated by a Holographic Optical Element (HOE) containing the functions of the Spiral Phase Plate (SPP) and an axicon. However the HOBB's large focal depth reduces the intensity at each plane. In this paper, we propose a multifunctional Diffractive Optical Element (DOE) containing the functions of a SPP, axicon and a Fresnel Zone Lens (FZL) to generate higher efficiency higher order Bessel-like-beams with a reduced focal depth. The functions of a SPP and a FZL were combined by shifting the location of zones of FZL in a spiral fashion. The resulting element is combined with an axicon by modulo-2π phase addition technique. The final composite element contains the functions of SPP, FZL and axicon. The elements were designed with different topological charges and fabricated using electron beam direct writing. The elements were tested and the generation of a higher order Bessel-like-beams is confirmed. Besides, the elements also generated high quality donut beams at two planes equidistant from the focal plane of the FZL.

  8. Method of Bonding Optical Elements with Near-Zero Displacement

    NASA Technical Reports Server (NTRS)

    Robinson, David; McClelland, Ryan; Byron, Glenn; Evans, Tyler

    2012-01-01

    The International X-ray Project seeks to build an x-ray telescope using thousands of pieces of thin and flexible glass mirror segments. Each mirror segment must be bonded into a housing in nearly perfect optical alignment without distortion. Forces greater than 0.001 Newton, or displacements greater than 0.5 m of the glass, cause unacceptable optical distortion. All known epoxies shrink as they cure. Even the epoxies with the least amount of shrinkage (<0.01%) cause unacceptable optical distortion and misalignment by pulling the mirror segments towards the housing as it cures. A related problem is that the shrinkage is not consistent or predictable so that it cannot be accounted for in the setup (i.e., if all of the bonds shrunk an equal amount, there would be no problem). A method has been developed that allows two components to be joined with epoxy in such a way that reduces the displacement caused by epoxy shrinking as it cures to less than 200 nm. The method involves using ultraviolet-cured epoxy with a displacement sensor and a nanoactuator in a control loop. The epoxy is cured by short-duration exposures to UV light. In between each exposure, the nano-actuator zeroes out the displacement caused by epoxy shrinkage and thermal expansion. After a few exposures, the epoxy has cured sufficiently to prevent further displacement of the two components. Bonding of optical elements has been done for many years, but most optics are thick and rigid elements that resist micro-Newton-level forces without causing distortion. When bonding thin glass optics such as the 0.40-mm thick IXO X-ray mirrors, forces in the micro- and milli-Newton levels cause unacceptable optical figure error. This innovation can now repeatedly and reliably bond a thin glass mirror to a metal housing with less than 0.2 m of displacement (<200 nm). This is an enabling technology that allows the installation of virtually stress-free, undistorted thin optics onto structures. This innovation is

  9. Traceability of high focal length cameras with diffractive optical elements

    NASA Astrophysics Data System (ADS)

    Lages Martins, L.; Silva Ribeiro, A.; Sousa, J. Alves e.

    2016-11-01

    This paper describes the use of diffractive optical elements (DOEs) for metrological traceable geometrical testing of high focal length cameras applied in the observation of large- scale structures. DOEs and related mathematical models are briefly explained. Laboratorial activities and results are described for the case of a high focal length camera used for longdistance displacement measurement of a long-span (2278 m) suspension bridge.

  10. Optical image encryption with a polarization-selective diffractive optical element based on interference

    NASA Astrophysics Data System (ADS)

    Zhu, Nan; Wang, Yongtian; Liu, Juan; Xie, Jinghui

    2010-11-01

    Data security techniques based on optical theories and methods have been proposed and widely developed in recent years. Compared with conventional mathematical encryption methods optical security system provides higher processing speed, more information volume, more encryption free-degree as well as its multi-dimension and parallel processing abilities. In this paper we proposed a novel architecture for optical image encryption with polarization-selective diffractive optical element (PDOE) based on interference theory. A target image is firstly encoded into two phase-only distributions and then these phase distributions are encrypted into the etched surface-relief pattern of a single PDOE mask. In the process of optical image decryption, when the working wavelength and the system configuration are correct, the PDOE mask with the encoded information for the target image can generate two desired polarized wavefronts by modulating the incident light beam. These two wavefronts interfere and then generate the decrypted image. The encoding algorithm to generate the phase-only distributions is simple and it does not need iterative process. The optical realization for image decryption also has the advantages of easier installation and collimation since all the optical elements are in a same optical axis. The employment of the PDOE mask in this optical security system will highly increase the information security and still maintain the parameter sensitivity in an acceptable region. Numerical simulation is performed to demonstrate the validity of this new proposed method.

  11. Simply scan--optical methods for elemental carbon measurement in diesel exhaust particulate.

    PubMed

    Forder, James A

    2014-08-01

    This article describes a performance assessment of three optical methods, a Magee Scientific OT21 Transmissometer, a Hach-Lange Microcolor II difference gloss meter, and a combination of an office scanner with Adobe Photoshop software. The optical methods measure filter staining as a proxy for elemental carbon in diesel exhaust particulate (DEP) exposure assessment and the suitability of each as a replacement for the existing Bosch meter optical method. Filters loaded with DEP were produced from air in a non-coal mine and the exhaust gases from a mobile crane. These were measured with each apparatus and then by combustion to obtain a reference elemental carbon value. The results from each apparatus were then plotted against both the Bosch number and reference elemental carbon values. The equations of the best fit lines for these plots were derived, and these gave functions for elemental carbon and Bosch number from the output of each new optical method. For each optical method, the range of DEP loadings which can be measured has been determined, and conversion equations for elemental carbon and Bosch number have been obtained. All three optical methods studied will effectively quantify blackness as a measure of elemental carbon. Of these the Magee Scientific OT21 transmissometer has the best performance. The Microcolor II and scanner/photoshop methods will in addition allow conversion to Bosch number which may be useful if historical Bosch data are available and functions for this are described. The scanner/photoshop method demonstrates a technique to obtain measurements of DEP exposure without the need to purchase specialized instrumentation.

  12. Temperature control system for optical elements in astronomical instrumentation

    NASA Astrophysics Data System (ADS)

    Verducci, Orlando; de Oliveira, Antonio C.; Ribeiro, Flávio F.; Vital de Arruda, Márcio; Gneiding, Clemens D.; Fraga, Luciano

    2014-07-01

    Extremely low temperatures may damage the optical components assembled inside of an astronomical instrument due to the crack in the resin or glue used to attach lenses and mirrors. The environment, very cold and dry, in most of the astronomical observatories contributes to this problem. This paper describes the solution implemented at SOAR for remotely monitoring and controlling temperatures inside of a spectrograph, in order to prevent a possible damage of the optical parts. The system automatically switches on and off some heat dissipation elements, located near the optics, as the measured temperature reaches a trigger value. This value is set to a temperature at which the instrument is not operational to prevent malfunction and only to protect the optics. The software was developed with LabVIEWTM and based on an object-oriented design that offers flexibility and ease of maintenance. As result, the system is able to keep the internal temperature of the instrument above a chosen limit, except perhaps during the response time, due to inertia of the temperature. This inertia can be controlled and even avoided by choosing the correct amount of heat dissipation and location of the thermal elements. A log file records the measured temperature values by the system for operation analysis.

  13. Process monitoring of additive manufacturing by using optical tomography

    SciTech Connect

    Zenzinger, Guenter E-mail: alexander.ladewig@mtu.de; Bamberg, Joachim E-mail: alexander.ladewig@mtu.de; Ladewig, Alexander E-mail: alexander.ladewig@mtu.de; Hess, Thomas E-mail: alexander.ladewig@mtu.de; Henkel, Benjamin E-mail: alexander.ladewig@mtu.de; Satzger, Wilhelm E-mail: alexander.ladewig@mtu.de

    2015-03-31

    Parts fabricated by means of additive manufacturing are usually of complex shape and owing to the fabrication procedure by using selective laser melting (SLM), potential defects and inaccuracies are often very small in lateral size. Therefore, an adequate quality inspection of such parts is rather challenging, while non-destructive-techniques (NDT) are difficult to realize, but considerable efforts are necessary in order to ensure the quality of SLM-parts especially used for aerospace components. Thus, MTU Aero Engines is currently focusing on the development of an Online Process Control system which monitors and documents the complete welding process during the SLM fabrication procedure. A high-resolution camera system is used to obtain images, from which tomographic data for a 3dim analysis of SLM-parts are processed. From the analysis, structural irregularities and structural disorder resulting from any possible erroneous melting process become visible and may be allocated anywhere within the 3dim structure. Results of our optical tomography (OT) method as obtained on real defects are presented.

  14. Multi-elemental analysis of aqueous geological samples by inductively coupled plasma-optical emission spectrometry

    USGS Publications Warehouse

    Todorov, Todor I.; Wolf, Ruth E.; Adams, Monique

    2014-01-01

    Typically, 27 major, minor, and trace elements are determined in natural waters, acid mine drainage, extraction fluids, and leachates of geological and environmental samples by inductively coupled plasma-optical emission spectrometry (ICP-OES). At the discretion of the analyst, additional elements may be determined after suitable method modifications and performance data are established. Samples are preserved in 1–2 percent nitric acid (HNO3) at sample collection or as soon as possible after collection. The aqueous samples are aspirated into the ICP-OES discharge, where the elemental emission signals are measured simultaneously for 27 elements. Calibration is performed with a series of matrix-matched, multi-element solution standards.

  15. Micro-optical elements and optical materials of certain spider webs

    NASA Astrophysics Data System (ADS)

    Kane, D. M.; Naidoo, N.; Little, D. J.

    2012-06-01

    Certain spider webs are composed of several types of micro-optical elements made from transparent optical materials. The silks (radial and capture) are almost exclusively protein. The nearly cylindrical silks have diameters in the range 0.1 to several microns and cross-sectional morphology that is cylindrical-multi-layered,.as studied by transmission electron microscopy, The capture threads are coated with aqueous adhesive that also forms into nearly elliptical micro-lenses (adhesive droplets) mounted on the near cylindrical silks. The remaining elements of the web are the cement junctions tying the radial and the capture threads of the web together. These are irregularly shaped platelets. Progress to date on our research characterizing the optical properties and function of these transparent orb webs has been to interpret the reflection and transmission properties of the elements of the web, and the web as a whole, in natural lighting; to evaluate the optical finish of the surface of the silks and capture droplets; and to measure the principal refractive indices of radial silks using new immersion based methods developed for application to micron-sized, curved optical elements. Here we report the principal refractive indices, birefringence, dispersion and morphology of transparent spider silk subject to various chemical treatments. The morphology is measured using TEM. Insight into the physical origin of the refractive index properties will be discussed.

  16. Fast character projection electron beam lithography for diffractive optical elements

    NASA Astrophysics Data System (ADS)

    Harzendorf, Torsten; Fuchs, Frank; Banasch, Michael; Zeitner, Uwe D.

    2014-05-01

    Electron beam lithography becomes attractive also for the fabrication of large scale diffractive optical elements by the use of the character projection (CP) technique. Even in the comparable fast variable shaped beam (VSB) exposure approach for conventional electron beam writers optical nanostructures may require very long writing times exceeding 24 hours per wafer because of the high density of features, as required by e.g. sub-wavelength nanostructures. Using character projection, the writing time can be reduced by more than one order of magnitude, due to the simultaneous exposure of multiple features. The benefit of character projection increases with increasing complexity of the features and decreasing period. In this contribution we demonstrate the CP technique for a grating of hexagonal symmetry at 350nm period. The pattern is designed to provide antireflective (AR) properties, which can be adapted in their spectral and angular domain for applications from VIS to NIR by changing the feature size and the etching depth of the nanostructure. This AR nanostructure can be used on the backside of optical elements e.g. gratings, when an AR coating stack could not be applied for the reason of climatic conditions or wave front accuracy.

  17. Simple fiber-optic autocollimation method for determining the focal lengths of optical elements.

    PubMed

    Ilev, I K

    1995-03-15

    A novel simple fiber-optic autocollimation method for determining the focal lengths of lenses and objectives is presented. This method is based on the intensity sensing of reflected light, photoelectric measurement, and the use of single-mode optical fiber. This fiber serves simultaneously as a point light source for the formation of a collimated input laser beam and as a receiver that is highly sensitive to spatial displacements for the autocollimation backreflectance. The method permits us to locate the focal point spatially and to determine the back focal length of a focusing optical element with accuracies exceeding 1 and 2 microm, respectively, which are confirmed by both experimental and analytical investigations.

  18. Beam shaping in flow cytometry with diffractive optical elements

    NASA Astrophysics Data System (ADS)

    Qu, Weidong; Li, Derong; Jian, Peng

    2016-10-01

    Focusing elements are usually employed in the flow cytometry to focus the input laser beam into elliptically shaped Gaussian beam in order to increase power for excitation of fluorescence for high signal-to-noise ratio (SNR). While in order to ensure repeatable and reliable signal generation for accurate population discrimination - despite slight deviations of the cell from the flow centre, the shaped beam should be a cubic diffraction region with uniform power intensity across the cell flow stream. However, it is hard for beam shaping with refractive optical elements. In this paper, we present a beam shaping system in flow cytometry with diffractive optical elements (DOEs) to shape the input laser beam to a cubic diffraction region with uniform power intensity. The phase distribution of the DOE is obtained by using the inverse Fresnel diffraction based layered holographic stereogram, and the cubic diffraction region with uniform power intensity within the cell flow channel is well reconstructed. Simulation results demonstrate the good performance of the new beam shaping system.

  19. Lasing optical cavities based on macroscopic scattering elements

    NASA Astrophysics Data System (ADS)

    Consoli, Antonio; López, Cefe

    2017-01-01

    Two major elements are required in a laser device: light confinement and light amplification. Light confinement is obtained in optical cavities by employing a pair of mirrors or by periodic spatial modulation of the refractive index as in photonic crystals and Bragg gratings. In random lasers, randomly placed nanoparticles embedded in the active material provide distributed optical feedback for lasing action. Recently, we demonstrated a novel architecture in which scattering nanoparticles and active element are spatially separated and random lasing is observed. Here we show that this approach can be extended to scattering media with macroscopic size, namely, a pair of sand grains, which act as feedback elements and output couplers, resulting in lasing emission. We demonstrate that the number of lasing modes depends on the surface roughness of the sand grains in use which affect the coherent feedback and thus the emission spectrum. Our findings offer a new perspective of material science and photonic structures, facilitating a novel and simple approach for the realization of new photonics devices based on natural scattering materials.

  20. Lasing optical cavities based on macroscopic scattering elements.

    PubMed

    Consoli, Antonio; López, Cefe

    2017-01-10

    Two major elements are required in a laser device: light confinement and light amplification. Light confinement is obtained in optical cavities by employing a pair of mirrors or by periodic spatial modulation of the refractive index as in photonic crystals and Bragg gratings. In random lasers, randomly placed nanoparticles embedded in the active material provide distributed optical feedback for lasing action. Recently, we demonstrated a novel architecture in which scattering nanoparticles and active element are spatially separated and random lasing is observed. Here we show that this approach can be extended to scattering media with macroscopic size, namely, a pair of sand grains, which act as feedback elements and output couplers, resulting in lasing emission. We demonstrate that the number of lasing modes depends on the surface roughness of the sand grains in use which affect the coherent feedback and thus the emission spectrum. Our findings offer a new perspective of material science and photonic structures, facilitating a novel and simple approach for the realization of new photonics devices based on natural scattering materials.

  1. Lasing optical cavities based on macroscopic scattering elements

    PubMed Central

    Consoli, Antonio; López, Cefe

    2017-01-01

    Two major elements are required in a laser device: light confinement and light amplification. Light confinement is obtained in optical cavities by employing a pair of mirrors or by periodic spatial modulation of the refractive index as in photonic crystals and Bragg gratings. In random lasers, randomly placed nanoparticles embedded in the active material provide distributed optical feedback for lasing action. Recently, we demonstrated a novel architecture in which scattering nanoparticles and active element are spatially separated and random lasing is observed. Here we show that this approach can be extended to scattering media with macroscopic size, namely, a pair of sand grains, which act as feedback elements and output couplers, resulting in lasing emission. We demonstrate that the number of lasing modes depends on the surface roughness of the sand grains in use which affect the coherent feedback and thus the emission spectrum. Our findings offer a new perspective of material science and photonic structures, facilitating a novel and simple approach for the realization of new photonics devices based on natural scattering materials. PMID:28071675

  2. Addition of three-dimensional isoparametric elements to NASA structural analysis program (NASTRAN)

    NASA Technical Reports Server (NTRS)

    Field, E. I.; Johnson, S. E.

    1973-01-01

    Implementation is made of the three-dimensional family of linear, quadratic and cubic isoparametric solid elements into the NASA Structural Analysis program, NASTRAN. This work included program development, installation, testing, and documentation. The addition of these elements to NASTRAN provides a significant increase in modeling capability particularly for structures requiring specification of temperatures, material properties, displacements, and stresses which vary throughout each individual element. Complete program documentation is presented in the form of new sections and updates for direct insertion to the three NASTRAN manuals. The results of demonstration test problems are summarized. Excellent results are obtained with the isoparametric elements for static, normal mode, and buckling analyses.

  3. Reflectionless design of optical elements using impedance-tunable transformation optics

    SciTech Connect

    Cao, Jun; Zhang, Lifa; Yan, Senlin; Sun, Xiaohan

    2014-05-12

    We report a strategy to remove the reflections resulted from the finite embedded transformation-optical design by proposing a theory of impedance-tunable transformation optics, on which the functions of impedance coefficients can be derived in the original space without changing the refractive index. Based on the approach, two-dimensional reflectionless beam compressors/expanders, bends, shifters, and splitters are designed using the modified anisotropic medium. It is found that the reflections can be removed in magnetic response materials for TE polarization or dielectric response materials for TM polarization. The numerical simulations confirm that various reflectionless optical elements can be realized in the pure transformation optics. The proposed method can be generalized to three-dimensional cases and can be applied to other transformation-optical designs.

  4. Single Element 2-DIMENSIONAL Acousto-Optic Deflectors Design, Fabrication and Implementation for Digital Optical Computing

    NASA Astrophysics Data System (ADS)

    Rosemeier, Jolanta Iwona

    1992-09-01

    With the need to develop very fast computers compared to the conventional digital chip based systems, the future is very bright for optical based signal processing. Attention has turned to a different application of optics utilizing mathematical operations, in which case operations are numerical, sometimes discrete, and often algebraic in nature. Interest has been so vigorous that many view it as a small revolution in optics whereby optical signal processing is beginning to encompass what many frequently describe as optical computing. The term is fully intended to imply close comparison with the operations performed by scientific digital computers. Most present computer intensive problem solving processors rely on a common set of linear equations found in numerical matrix algebra. Recently, considerable research focused on the use of systolic array, which can operate at high speeds with great efficiency. This approach addresses the acousto-optic digital and analog arrays utilizing three dimensional optical interconnect technology. In part I of this dissertation the first single element 2-dimensional (2-D) acousto-optic deflector was designed, fabricated and incorporated into an optical 3 x 3 vector-vector or matrix-matrix multiplier system. This single element deflector is used as a outer-product device. The input vectors are addressed by electronic means and the outer product matrix is displayed as a 2-D array of optical (laser) pixels. In part II of this work a multichannel single element 2-D deflector was designed, fabricated and implemented into a Programmable Logic Array (PLA) optical computing system. This system can be used for: word equality detection, free space optical interconnections, half adder optical system implementation. The PLA system described in this dissertation has capability of word equality detection. The 2-D multichannel deflector that was designed and fabricated is capable of comparing 16 x 16 words every 316 nanoseconds. Each word is 8

  5. Fourier holographic display for augmented reality using holographic optical element

    NASA Astrophysics Data System (ADS)

    Li, Gang; Lee, Dukho; Jeong, Youngmo; Lee, Byoungho

    2016-03-01

    A method for realizing a three-dimensional see-through augmented reality in Fourier holographic display is proposed. A holographic optical element (HOE) with the function of Fourier lens is adopted in the system. The Fourier hologram configuration causes the real scene located behind the lens to be distorted. In the proposed method, since the HOE is transparent and it functions as the lens just for Bragg matched condition, there is not any distortion when people observe the real scene through the lens HOE (LHOE). Furthermore, two optical characteristics of the recording material are measured for confirming the feasibility of using LHOE in the proposed see-through augmented reality holographic display. The results are verified experimentally.

  6. Single crystal optic elements for helium atom microscopy

    NASA Astrophysics Data System (ADS)

    MacLaren, D. A.; Allison, W.; Holst, B.

    2000-07-01

    Focusing characteristics of asymmetrically bent single crystal mirrors are discussed in the context of fabricating an optic element for an helium atom microscope. We demonstrate the principle that deforming a clamped, elliptical, single crystal under electrostatic pressure can produce submicron focusing of an helium beam. We present a systematic procedure that may be used to fabricate high precision mirrors close to the Cartesian ideal of any chosen optical configuration. In particular, imaging systems with asymmetric mirror profiles are discussed. Results are independent of crystal characteristics and can be adapted to fit a range of experimental geometries. The calculations indicate that mirror-induced aberrations can be eliminated to fourth order by use of a single actuation electrode in an ideal system.

  7. James Webb Space Telescope Optical Telescope Element Mirror Coatings

    NASA Technical Reports Server (NTRS)

    Keski-Kuha, Ritva A.; Bowers, Charles W.; Quijada, Manuel A.; Heaney, James B.; Gallagher, Benjamin; McKay, Andrew; Stevenson, Ian

    2012-01-01

    James Webb Space Telescope (JWST) Optical Telescope Element (OTE) mirror coating program has been completed. The science goals of the JWST mission require a uniform, low stress, durable optical coating with high reflectivity over the JWST spectral region. The coating has to be environmentally stable, radiation resistant and compatible with the cryogenic operating environment. The large size, 1.52 m point to point, light weight, beryllium primary mirror (PM) segments and flawless coating process during the flight mirror coating program that consisted coating of 21 flight mirrors were among many technical challenges. This paper provides an overview of the JWST telescope mirror coating program. The paper summarizes the coating development program and performance of the flight mirrors.

  8. Arbitrarily complete Bell-state measurement using only linear optical elements

    SciTech Connect

    Grice, W. P.

    2011-10-15

    A complete Bell-state measurement is not possible using only linear-optic elements, and most schemes achieve a success rate of no more than 50%, distinguishing, for example, two of the four Bell states but returning degenerate results for the other two. It is shown here that the introduction of a pair of ancillary entangled photons improves the success rate to 75%. More generally, the addition of 2{sup N}-2 ancillary photons yields a linear-optic Bell-state measurement with a success rate of 1-1/2{sup N}.

  9. Design the diffractive optical element with large diffraction angle

    NASA Astrophysics Data System (ADS)

    Pang, Hui; Yin, Shaoyun; Zheng, Guoxing; Deng, Qiling; Shi, Lifang; Du, Chunlei

    2014-11-01

    In this paper, a quite effective method is proposed for designing the diffractive optical element (DOE) to generate a pattern with large diffraction angle. Through analyze the difference between the non-paraxial Rayleigh Sommerfeld integral and the paraxial Fraunhofer diffraction integral, we modify the desired output intensity distribution with coordinate transformation and intensity adjustment. Then the paraxial Fraunhofer diffraction integral can be used to design the DOE, which adopts the fast-Fourier-transform (FFT) algorithm to accelerate the computation. To verify our method, the simulation and the experiments are taken. And the result shows that our method can effectively rectify the pillow distortion and can achieve the exact diffraction angle.

  10. Compact generation of superposed higher-order Bessel beams via composite diffractive optical elements

    NASA Astrophysics Data System (ADS)

    Vijayakumar, Anand; Bhattacharya, Shanti

    2015-11-01

    Binary composite diffractive optical elements with the functions of a spiral phase plate (SPP), an axicon, and a Fresnel zone lens (FZL) were designed with different topological charges. The element was designed in two steps. In the first step, the function of an SPP was combined with that of an axicon by spiraling the periods of the axicon with respect to the phase of the SPP followed by a modulo-2π phase addition with the phase of an FZL in the second step. The higher-order Bessel beams generated by the binary phase spiral axicon are superposed at the FZL's focal plane. Although location of the focal plane is wavelength dependent, the radius of the flower-like beams generated by the element was found to be independent of wavelength. The element was fabricated using electron-beam direct writing. The evaluation results matched well with the simulation results, generating flower-like beams at the focal plane of the FZL.

  11. Co-digestion of manure and industrial waste--The effects of trace element addition.

    PubMed

    Nordell, Erik; Nilsson, Britt; Nilsson Påledal, Sören; Karisalmi, Kaisa; Moestedt, Jan

    2016-01-01

    Manure is one of the most common substrates for biogas production. Manure from dairy- and swine animals are often considered to stabilize the biogas process by contributing nutrients and trace elements needed for the biogas process. In this study two lab-scale reactors were used to evaluate the effects of trace element addition during co-digestion of manure from swine- and dairy animals with industrial waste. The substrate used contained high background concentrations of both cobalt and nickel, which are considered to be the most important trace elements. In the reactor receiving additional trace elements, the volatile fatty acids (VFA) concentration was 89% lower than in the control reactor. The lower VFA concentration contributed to a more digested digestate, and thus lower methane emissions in the subsequent storage. Also, the biogas production rate increased with 24% and the biogas production yield with 10%, both as a result of the additional trace elements at high organic loading rates. All in all, even though 50% of the feedstock consisted of manure, trace element addition resulted in multiple positive effects and a more reliable process with stable and high yield.

  12. Multivariate optical element platform for compressed detection of fluorescence markers

    NASA Astrophysics Data System (ADS)

    Priore, Ryan J.; Swanstrom, Joseph A.

    2014-05-01

    The success of a commercial fluorescent diagnostic assay is dependent on the selection of a fluorescent biomarker; due to the broad nature of fluorescence biomarker emission profiles, only a small number of fluorescence biomarkers may be discriminated from each other as a function of excitation source. Multivariate Optical Elements (MOEs) are thin-film devices that encode a broad band, spectroscopic pattern allowing a simple broadband detector to generate a highly sensitive and specific detection for a target analyte. MOEs have historically been matched 1:1 to a discrete analyte or class prediction; however, MOE filter sets are capable of sensing projections of the original sparse spectroscopic space enabling a small set of MOEs to discriminate a multitude of target analytes. This optical regression can offer real-time measurements with relatively high signal-to-noise ratios that realize the advantages of multiplexed detection and pattern recognition in a simple optical instrument. The specificity advantage of MOE-based sensors allows fluorescent biomarkers that were once incapable of discrimination from one another via optical band pass filters to be employed in a common assay panel. A simplified MOE-based sensor may ultimately reduce the requirement for highly trained operators as well as move certain life science applications like disease prognostication from the laboratory to the point of care. This presentation will summarize the design and fabrication of compressed detection MOE filter sets for detecting multiple fluorescent biomarkers simultaneously with strong spectroscopic interference as well as comparing the detection performance of the MOE sensor with traditional optical band pass filter methodologies.

  13. Analysis of synthetic motor oils for additive elements by ICP-AES

    SciTech Connect

    Williams, M.C.; Salmon, S.G.

    1995-12-31

    Standard motor oils are made by blending paraffinic or naphthenic mineral oil base stocks with additive packages containing anti-wear agents, dispersants, corrosion inhibitors, and viscosity index improvers. The blender can monitor the correct addition of the additives by determining the additive elements in samples dissolved in a solvent by ICP-AES. Internal standardization is required to control sample transport interferences due to differences in viscosity between samples and standards. Synthetic motor oils, made with poly-alpha-olefins and trimethylol propane esters, instead of mineral oils, pose an additional challenge since these compounds affect the plasma as well as having sample transport interference considerations. The synthetic lubricant base stocks add significant oxygen to the sample matrix, which makes the samples behave differently than standards prepared in mineral oil. Determination of additive elements in synthetic motor oils will be discussed.

  14. Multiple-Zone Diffractive Optic Element for Laser Ranging Applications

    NASA Technical Reports Server (NTRS)

    Ramos-Izquierdo, Luis A.

    2011-01-01

    A diffractive optic element (DOE) can be used as a beam splitter to generate multiple laser beams from a single input laser beam. This technology has been recently used in LRO s Lunar Orbiter Laser Altimeter (LOLA) instrument to generate five laser beams that measure the lunar topography from a 50-km nominal mapping orbit (see figure). An extension of this approach is to use a multiple-zone DOE to allow a laser altimeter instrument to operate over a wider range of distances. In particular, a multiple-zone DOE could be used for applications that require both mapping and landing on a planetary body. In this case, the laser altimeter operating range would need to extend from several hundred kilometers down to a few meters. The innovator was recently involved in an investigation how to modify the LOLA instrument for the OSIRIS asteroid mapping and sample return mission. One approach is to replace the DOE in the LOLA laser beam expander assembly with a multiple-zone DOE that would allow for the simultaneous illumination of the asteroid with mapping and landing laser beams. The proposed OSIRIS multiple-zone DOE would generate the same LOLA five-beam output pattern for high-altitude topographic mapping, but would simultaneously generate a wide divergence angle beam using a small portion of the total laser energy for the approach and landing portion of the mission. Only a few percent of the total laser energy is required for approach and landing operations as the return signal increases as the inverse square of the ranging height. A wide divergence beam could be implemented by making the center of the DOE a diffractive or refractive negative lens. The beam energy and beam divergence characteristics of a multiple-zone DOE could be easily tailored to meet the requirements of other missions that require laser ranging data. Current single-zone DOE lithographic manufacturing techniques could also be used to fabricate a multiple-zone DOE by masking the different DOE zones during

  15. Cryogenic Optical Position Encoders for Mechanisms in the JWST Optical Telescope Element Simulator (OSIM)

    NASA Technical Reports Server (NTRS)

    Leviton, Douglas B.; Anderjaska, Thomas; Badger, James (Inventor); Capon, Tom; Davis, CLinton; Dicks, Brent (Inventor); Eichhorn, William; Garza, Mario; Guishard, Corina; Haghani, Shadan; Hakun, Claef; Haney, Paul; Happs, David (Inventor); Hovmand, Lars; Kadari, Madhu; Kirk, Jeffrey; Nyquist, Richard (Inventor); Robinson, F. David; Sullivan, Joseph (Inventor); Wilson, Erin

    2013-01-01

    The JWST Optical Telescope Element Simulator (OSIM) is a configurable, cryogenic, optical stimulus for high fidelity ground characterization and calibration of JWST's flight instruments. OSIM and its associated Beam Image Analyzer (BIA) contain several ultra-precise, cryogenic mechanisms that enable OSIM to project point sources into the instruments according to the same optical prescription as the flight telescope images stars - correct in focal surface position and chief ray angle. OSIM's and BIA's fifteen axes of mechanisms navigate according to redundant, cryogenic, absolute, optical encoders - 32 in all operating at or below 100 K. OSIM's encoder subsystem, the engineering challenges met in its development, and the encoders' sub-micron and sub-arcsecond performance are discussed.

  16. Effect of lubricant extreme pressure additives on rolling element fatigue life

    NASA Technical Reports Server (NTRS)

    Parker, R. J.; Zaretsky, E. V.

    1973-01-01

    The effects of surface active additives on rolling-element fatigue life were investigated with the five-ball fatigue tester at conditions where classical subsurface initiated rolling-element fatigue is the sole mode of failure. Test balls of AISI 52100, AISI M-50, and AISI 1018 were run with an acid-treated white oil containing either 2.5 percent sulfurized terpene, 1 percent didodecyl phosphite, or 5 percent chlorinated wax. In general, it was found that the influence of surface active additives was detrimental to rolling-element fatigue life. The chlorinated-wax additive significantly reduced fatigue life by a factor of 7. The base oil with the 2.5 percent sulfurized-terpene additive can reduce fatigue life by as much as 50 percent. No statistical change in fatigue life occurred with the base oil having the 1 percent didodecyl-phosphite additive. The additives used with the base oil did not change the ranking of the bearing steels where rolling-element fatigue life was of subsurface origin.

  17. Adaptive optics vision simulation and perceptual learning system based on a 35-element bimorph deformable mirror.

    PubMed

    Dai, Yun; Zhao, Lina; Xiao, Fei; Zhao, Haoxin; Bao, Hua; Zhou, Hong; Zhou, Yifeng; Zhang, Yudong

    2015-02-10

    An adaptive optics visual simulation combined with a perceptual learning (PL) system based on a 35-element bimorph deformable mirror (DM) was established. The larger stroke and smaller size of the bimorph DM made the system have larger aberration correction or superposition ability and be more compact. By simply modifying the control matrix or the reference matrix, select correction or superposition of aberrations was realized in real time similar to a conventional adaptive optics closed-loop correction. PL function was first integrated in addition to conventional adaptive optics visual simulation. PL training undertaken with high-order aberrations correction obviously improved the visual function of adult anisometropic amblyopia. The preliminary application of high-order aberrations correction with PL training on amblyopia treatment was being validated with a large scale population, which might have great potential in amblyopia treatment and visual performance maintenance.

  18. Modeling the behavior of optical elements in radiation environments

    SciTech Connect

    Barlow, T.A.; Rhoades, C.E. Jr.; Merker, M.; Triplett, J.R.

    1986-11-03

    Calculation of heating caused by the deposition of x-rays in thin film optical elements is complicated because the mean free path of photo and autoionization electrons is comparable to the thin film thickness and thus the electron deposition cannot be considered local. This paper describes the modeling in a 1-D code of: (a) x-ray deposition and transport; (b) electron production, deposition and transport; and (c) thermal conduction and transport. X-ray transport is handled by multigroup discrete ordinates, electron transport is done by the method of characteristics, applied to the two term spherical harmonics expansion approximation (P1) to the Spencer-Lewis transport equation, and thermal transport is computed by a simple Richardson extrapolation of a backward Euler solution to the heat conduction equations. Results of a few test cases are presented. 8 refs., 26 figs., 2 tabs.

  19. Biological elements carry out optical tasks in coherent imaging systems

    NASA Astrophysics Data System (ADS)

    Ferraro, P.; Bianco, V.; Paturzo, M.; Miccio, L.; Memmolo, P.; Merola, F.; Marchesano, V.

    2016-03-01

    We show how biological elements, like live bacteria species and Red Blood Cells (RBCs) can accomplish optical functionalities in DH systems. Turbid media allow coherent microscopy despite the strong light scattering these provoke, acting on light just as moving diffusers. Furthermore, a turbid medium can have positive effects on a coherent imaging system, providing resolution enhancement and mimicking the action of noise decorrelation devices, thus yielding an image quality significantly higher than the quality achievable through a transparent medium in similar recording conditions. Besides, suspended RBCs are demonstrated to behave as controllable liquid micro-lenses, opening new possibilities in biophotonics for endoscopy imaging purposes, as well as telemedicine for point-of-care diagnostics in developing countries and low-resource settings.

  20. Effect of aluminum and tellurium tetrachloride addition on the loss of arsenic selenide optical fiber

    NASA Astrophysics Data System (ADS)

    Nguyen, Vinh Q.; Drake, Gryphon; Villalobos, Guillermo; Gibson, Daniel; Bayya, Shyam; Kim, Woohong; Baker, Colin; Chin, Geoff; Kung, Frederic H.; Kotov, Mikhail I.; Busse, Lynda; Sanghera, Jasbinder S.

    2017-02-01

    Arsenic selenide glass optical fibers typically possess extrinsic absorption bands in the infrared wavelength regions associated with residual hydrogen and oxygen related impurities, despite using 6N purified elemental precursors. Consequently, special additives and refined processing steps are utilized in an attempt to reduce these and other impurities. We investigate the formation of particulate impurities during a purification process based on the addition of 0.1 wt% elemental aluminum (Al) and 0.2 wt% tellurium tetrachloride (TeCl4) during glass synthesis. It was found that during purification and melting steps, Al reacts with TeCl4 to form AlCl3, which in turn reacts with oxygen and hydrogen impurities and the fused quartz (SiO2) ampoule to produce HCl and stable submicron Al2SiO5 compounds in the As-Se glass and fibers. The intensity of the H-Se absorption band centered at 4.57 μm has been significantly reduced from 18 dB/m to 0.8 dB/m. Using thermodynamic data, we have identified stable Al2SiO5 submicron inclusions in the glass and fibers. A two-step gettering process is proposed as a solution to eliminating these inclusions.

  1. Optical schemes for speckle suppression by Barker code diffractive optical elements.

    PubMed

    Lapchuk, A; Kryuchyn, A; Petrov, V; Shyhovets, O V; Pashkevich, G A; Bogdan, O V; Kononov, A; Klymenko, A

    2013-09-01

    A method for speckle suppression based on Barker code and M-sequence code diffractive optical elements (DOEs) is analyzed. An analytical formula for the dependence of speckle contrast on the wavelength of the laser illumination is derived. It is shown that speckle contrast has a wide maximum around the optimal wavelength that makes it possible to obtain large speckle suppression by using only one DOE for red, green, and blue laser illumination. Optical schemes for implementing this method are analyzed. It is shown that the method can use a simple liquid-crystal panel for phase rotation instead of a moving DOE; however, this approach requires a high frequency of liquid-crystal switching. A simple optical scheme is proposed using a 1D Barker code DOE and a simple 1D liquid-crystal panel, which does not require a high frequency of liquid-crystal switching or high-accuracy DOE movement.

  2. 41 CFR 60-2.17 - Additional required elements of affirmative action programs.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 41 Public Contracts and Property Management 1 2014-07-01 2014-07-01 false Additional required elements of affirmative action programs. 60-2.17 Section 60-2.17 Public Contracts and Property Management... EMPLOYMENT OPPORTUNITY, DEPARTMENT OF LABOR 2-AFFIRMATIVE ACTION PROGRAMS Purpose and Contents of...

  3. 41 CFR 60-2.17 - Additional required elements of affirmative action programs.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 41 Public Contracts and Property Management 1 2012-07-01 2009-07-01 true Additional required elements of affirmative action programs. 60-2.17 Section 60-2.17 Public Contracts and Property Management... EMPLOYMENT OPPORTUNITY, DEPARTMENT OF LABOR 2-AFFIRMATIVE ACTION PROGRAMS Purpose and Contents of...

  4. Optical design and multiobjective optimization of miniature zoom optics with liquid lens element.

    PubMed

    Sun, Jung-Hung; Hsueh, Bo-Ren; Fang, Yi-Chin; MacDonald, John; Hu, Chao-Chang

    2009-03-20

    We propose an optical design for miniature 2.5x zoom fold optics with liquid elements. First, we reduce the volumetric size of the system. Second, this newly developed design significantly reduces the number of moving groups for this 2.5x miniature zoom optics (with only two moving groups compared with the four or five groups of the traditional zoom lens system), thanks to the assistance of liquid lens elements in particular. With regard to the extended optimization of this zoom optics, relative illuminance (RI) and the modulation transfer function (MTF) are considered because the more rays passing through the edge of the image, the lower will be the MTF, at high spatial frequencies in particular. Extended optimization employs the integration of the Taguchi method and the robust multiple criterion optimization (RMCO) approach. In this approach, a Pareto optimal robust design solution is set with the aid of a certain design of the experimental set, which uses analysis of variance results to quantify the relative dominance and significance of the design factors. It is concluded that the Taguchi method and RMCO approach is successful in optimizing the RI and MTF values of the fold 2.5x zoom lens system and yields better and more balanced performance, which is very difficult for the traditional least damping square method to achieve.

  5. Sighting optics including an optical element having a first focal length and a second focal length and methods for sighting

    DOEpatents

    Crandall, David Lynn

    2011-08-16

    Sighting optics include a front sight and a rear sight positioned in a spaced-apart relation. The rear sight includes an optical element having a first focal length and a second focal length. The first focal length is selected so that it is about equal to a distance separating the optical element and the front sight and the second focal length is selected so that it is about equal to a target distance. The optical element thus brings into simultaneous focus for a user images of the front sight and the target.

  6. Accurate optical CD profiler based on specialized finite element method

    NASA Astrophysics Data System (ADS)

    Carrero, Jesus; Perçin, Gökhan

    2012-03-01

    As the semiconductor industry is moving to very low-k1 patterning solutions, the metrology problems facing process engineers are becoming much more complex. Choosing the right optical critical dimension (OCD) metrology technique is essential for bridging the metrology gap and achieving the required manufacturing volume throughput. The critical dimension scanning electron microscope (CD-SEM) measurement is usually distorted by the high aspect ratio of the photoresist and hard mask layers. CD-SEM measurements cease to correlate with complex three-dimensional profiles, such as the cases for double patterning and FinFETs, thus necessitating sophisticated, accurate and fast computational methods to bridge the gap. In this work, a suite of computational methods that complement advanced OCD equipment, and enabling them to operate at higher accuracies, are developed. In this article, a novel method for accurately modeling OCD profiles is presented. A finite element formulation in primal form is used to discretize the equations. The implementation uses specialized finite element spaces to solve Maxwell equations in two dimensions.

  7. Optical sensing elements for nitrogen dioxide (NO.sub.2) gas detection, a sol-gel method for making the sensing elements and fiber optic sensors incorporating nitrogen dioxide gas optical sensing elements

    DOEpatents

    Mechery, Shelly John; Singh, Jagdish P.

    2007-07-03

    A sensing element, a method of making a sensing element, and a fiber optic sensor incorporating the sensing element are described. The sensor can be used for the quantitative detection of NO.sub.2 in a mixture of gases. The sensing element can be made by incorporating a diazotizing reagent which reacts with nitrous ions to produce a diazo compound and a coupling reagent which couples with the diazo compound to produce an azo dye into a sol and allowing the sol to form an optically transparent gel. The sensing element changes color in the presence of NO.sub.2 gas. The temporal response of the absorption spectrum at various NO.sub.2 concentrations has also been recorded and analyzed. Sensors having different design configurations are described. The sensing element can detect NO.sub.2 gas at levels of parts per billion.

  8. Fabrication of Diffractive Optical Elements for an Integrated Compact Optical-MEMS Laser Scanner

    SciTech Connect

    WENDT,JOEL R.; KRYGOWSKI,T.W.; VAWTER,GREGORY A.; SPAHN,OLGA B.; SWEATT,WILLIAM C.; WARREN,MIAL E.; REYES,DAVID NMN

    2000-07-13

    The authors describe the microfabrication of a multi-level diffractive optical element (DOE) onto a micro-electromechanical system (MEMS) as a key element in an integrated compact optical-MEMS laser scanner. The DOE is a four-level off-axis microlens fabricated onto a movable polysilicon shuttle. The microlens is patterned by electron beam lithography and etched by reactive ion beam etching. The DOE was fabricated on two generations of MEMS components. The first generation design uses a shuttle suspended on springs and displaced by a linear rack. The second generation design uses a shuttle guided by roller bearings and driven by a single reciprocating gear. Both the linear rack and the reciprocating gear are driven by a microengine assembly. The compact design is based on mounting the MEMS module and a vertical cavity surface emitting laser (VCSEL) onto a fused silica substrate that contains the rest of the optical system. The estimated scan range of the system is {+-}4{degree} with a spot size of 0.5 mm.

  9. Enhancing Surface Finish of Additively Manufactured Titanium and Cobalt Chrome Elements Using Laser Based Finishing

    NASA Astrophysics Data System (ADS)

    Gora, Wojciech S.; Tian, Yingtao; Cabo, Aldara Pan; Ardron, Marcus; Maier, Robert R. J.; Prangnell, Philip; Weston, Nicholas J.; Hand, Duncan P.

    Additive manufacturing (AM) offers the possibility of creating a complex free form object as a single element, which is not possible using traditional mechanical machining. Unfortunately the typically rough surface finish of additively manufactured parts is unsuitable for many applications. As a result AM parts must be post-processed; typically mechanically machined and/or and polished using either chemical or mechanical techniques (both of which have their limitations). Laser based polishing is based on remelting of a very thin surface layer and it offers potential as a highly repeatable, higher speed process capable of selective area polishing, and without any waste problems (no abrasives or liquids). In this paper an in-depth investigation of CW laser polishing of titanium and cobalt chrome AM elements is presented. The impact of different scanning strategies, laser parameters and initial surface condition on the achieved surface finish is evaluated.

  10. Diffractive optical elements on non-flat substrates using electron beam lithography

    NASA Technical Reports Server (NTRS)

    Maker, Paul D. (Inventor); Muller, Richard E. (Inventor); Wilson, Daniel W. (Inventor)

    2002-01-01

    The present disclosure describes a technique for creating diffraction gratings on curved surfaces with electron beam lithography. The curved surface can act as an optical element to produce flat and aberration-free images in imaging spectrometers. In addition, the fabrication technique can modify the power structure of the grating orders so that there is more energy in the first order than for a typical grating. The inventors noticed that by using electron-beam lithography techniques, a variety of convex gratings that are well-suited to the requirements of imaging spectrometers can be manufactured.

  11. DESIGN NOTE: Optical sensing of colour print on paper by a diffractive optical element

    NASA Astrophysics Data System (ADS)

    Palviainen, Jari; Sorjonen, Mika; Silvennoinen, Raimo; Peiponen, Kai-Erik

    2002-04-01

    A diffractive optical element (DOE) based sensor was applied to investigate optical surface quality of two different commercial laser print papers before and after printing of red, green and blue colour ink. The DOE sensor provides simultaneously information on both reflected and transmitted light, whereas a spectrophotometer, which was applied as a corroborative method, yields non-simultaneous information about the total reflection and transmission from the samples. The DOE sensor images were analysed and information concerning the local anisotropy of the paper was obtained. The border between a colour print and non-print was also investigated using the DOE sensor and a microdensitometer. It is proposed that the DOE sensor provides better resolution of the border than the microdensitometer.

  12. Polarized diffractive optical element design for a multibeam optical pickup head

    NASA Astrophysics Data System (ADS)

    Shih, Hsi-Fu; Freeman, Mark O.; Ju, Jau-Jiu; Yang, Tzu-Ping; Lee, Yuan-Chin

    2000-07-01

    This paper addresses the design and construction of an interesting polarization-switched diffractive optical element (DOE) that generates multiple beams incident on the disk and acts as a beamsplitter and servo-generating element for light returning from the disk. In this way, data speed is increased proportional to the number of beams on the disk, and, by combining three functions into a single optical element, allows a more compact and lightweight pickup to be realized. The polarization-switched DOE is constructed as a sandwich of two pieces of some birefringent material, with one rotated by 90 degrees relative to the other so that the ordinary and extraordinary axes are interchanged, and with a common index-match layer between them. A diffractive pattern is etched into each of the two birefringent pieces. Linearly polarized light traveling from the laser towards the disk is diffracted into multiple beams by one of the diffractive patterns while experiencing no diffraction from the other. Travelling the roundtrip from the DOE to the disk and back to the DOE, the light traverses a quarter-wave retarder two times thereby rotating its polarization direction by 90 degrees. It now experiences no diffraction from the multiple beam diffraction layer, but is diffracted by the second diffraction layer, which steers it onto the photodetectors and alters the beam to create useful focus and tracking error signals. This design is important in that it provides a way for two diffractive surfaces, each acting independently with high efficiency on orthogonal polarizations of light, to be combined into a single element. Implementation and application to a multiple-beam holographic pickup head module are presented.

  13. Generation of Laguerre Gaussian beams using spiral phase diffractive elements fabricated on optical fiber tips using focused ion beam milling

    NASA Astrophysics Data System (ADS)

    Rodrigues Ribeiro, R. S.; Dahal, P.; Guerreiro, A.; Jorge, P. A. S.; Viegas, J.

    2016-03-01

    In this work, spiral phase lenses fabricated on the tip of single mode optical fibers are reported. This allows tailoring the fundamental guided mode, a Gaussian beam, into a Laguerre - Gaussian profile without using additional optical elements. The lenses are fabricated using Focused Ion Beam milling, enabling high resolution in the manufacturing process. The phase profiles are evaluated and validated using an implementation of the Finite Differences Time Domain. The output optical intensity profiles matching the numerical simulations are presented and analyzed. Finally, results on cell trapping and manipulation are briefly described.

  14. Additives

    NASA Technical Reports Server (NTRS)

    Smalheer, C. V.

    1973-01-01

    The chemistry of lubricant additives is discussed to show what the additives are chemically and what functions they perform in the lubrication of various kinds of equipment. Current theories regarding the mode of action of lubricant additives are presented. The additive groups discussed include the following: (1) detergents and dispersants, (2) corrosion inhibitors, (3) antioxidants, (4) viscosity index improvers, (5) pour point depressants, and (6) antifouling agents.

  15. Simulation of the optical performance of refractive elements to mimic the human eye focusing

    NASA Astrophysics Data System (ADS)

    Diaz-Gonzalez, G.; Santiago-Alvarado, Agustín.; Cruz-Félix, Ángel S.

    2015-09-01

    Refractive optics has evolved and incorporated new elements in optical systems every day, such as conventional lenses, tunable lenses, GRIN lenses, diffractive lenses, intraocular lenses, etc. Some of these elements are reported in the literature together with different proposed models of the human eye. In this work, optical properties of some of these lenses will be studied, and simulations of their behavior will be done in order to analyze which one is better for imaging process. Such lenses will be incorporated in an optical system that mimics the human eye behavior. Analysis and obtained results are reported, as well as the proposed optical system. Finally, we present the conclusions of the work.

  16. A tactile sensing element based on a hetero-core optical fiber for force measurement and texture detection

    NASA Astrophysics Data System (ADS)

    Yamazaki, Hiroshi; Koyama, Yuya; Watanabe, Kazuhiro

    2014-05-01

    Tactile sensing technology can measure a given property of an object through physical contact between a sensing element and the object. Various tactile sensing techniques have been developed for several applications such as intelligent robots, tactile interface, medical support and nursing care support. A desirable tactile sensing element for supporting human daily life can be embedded in the soft material with high sensitivity and accuracy in order to prevent from damaging to human or object physically. This report describes a new tactile sensing element. Hetero-core optical fibers have high sensitivity of macro-bending at local sensor portion and temperature independency, including advantages of optical fiber itself; thin size, light weight, flexible transmission line, and immunity to electro-magnetic interference. The proposed tactile sensing element could detect textures of touched objects through the optical loss caused by the force applied to the sensing element. The characteristics of the sensing element have been evaluated, in which the sensing element has the monotonic and non-linear sensitivity against the normal force ranged from 0 to 5 N with lower accuracy than 0.25 dB. Additionally, texture detection have been successfully demonstrated in which small surface figures of 0.1 mm in height were detected with spatial resolution of 0.4 mm.

  17. Impact of Zn, Mg, Ni and Co elements on glass alteration: Additive effects

    NASA Astrophysics Data System (ADS)

    Aréna, H.; Godon, N.; Rébiscoul, D.; Podor, R.; Garcès, E.; Cabie, M.; Mestre, J.-P.

    2016-03-01

    The minor elements present in the nuclear glass composition or coming from the groundwater of the future repository may impact glass alteration. In this study, the effects of Zn, Mg, Ni and Co on the International Simple Glass (ISG) alteration were studied throughout 511 days of aqueous leaching experiments. The aim was to determine their additive or competitive effect on glass alteration and the nature of the alteration products. The four elements were introduced separately or altogether in solution as XCl2 chloride salts (X = Zn, Mg, Ni or Co) with monthly additions to compensate for their consumption. The alteration kinetics were determined by leachate analyses (ICP-AES) and alteration products were characterized in terms of composition, morphology and microstructure (SEM, TEM-EDX, ToF-SIMS and XRD). Results indicate that when they are introduced separately, Zn, Mg, Ni and Co have the same qualitative and quantitative effect on glass alteration kinetics and on pH: they form secondary phases leading to a pH decrease and a significant increase in glass alteration. The secondary phases were identified as silicates of the added X element: trioctahedral smectites with a stoichiometry of[(Si(4-a) Ala) (X(3-b) Alb) O10 (OH)2](a+b)- [Xc Nad Cae] (2c+d+2e) + with a = 0.11 to 0.45, b = 0.00 to 0.29, c = 0, d = 0.19 to 0.74 and e = 0.10 to 0.14. . It was shown that as pH stabilizes at a minimum value, X-silicates no longer precipitate, thus leading to a significant drop in the glass alteration rate. This pH value depends on X and it has been identified as being 8 for Mg-silicates, probably around 7.3 for Ni and Co-silicates and less than 6.2 for Zn-silicates. When tested together, the effects of these four elements on glass alteration are additive and lead to the formation of a mix of X-silicates that precipitate as long as their constitutive elements are available and the pH is above their respective minimum value. This study brings new quantitative information about the

  18. Large Aperture Scanning Lidar Based on Holographic Optical Elements

    NASA Technical Reports Server (NTRS)

    Schwemmer, Geary K.; Miller, David O.; Wilkerson, Thomas D.; Andrus, Ionio; Guerra, David V.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    Lidar remote sensing instruments can make a significant contribution to satisfying many of the required measurements of atmospheric and surface parameters for future spaceborne platforms, including topographic altimeters, atmospheric profiles of, wind, humidity, temperature, trace molecules, aerosols, and clouds. It is highly desirable to have wide measurement swaths for rapid coverage rather than just the narrow ribbon of data that is obtained with a nadir only observation. For most applications global coverage is required, and for wind measurements scanning or pointing is required in order to retrieve the full 3-D wind vector from multiple line-of-sight Doppler measurements. Conventional lidar receivers make up a substantial portion of the instrument's size and weight. Wide angle scanning typically requires a large scanning mirror in front of the receiver telescope, or pointing the entire telescope and aft optics assembly, Either of these methods entails the use of large bearings, motors, gearing and their associated electronics. Spaceborne instruments also need reaction wheels to counter the torque applied to the spacecraft by these motions. NASA has developed simplified conical scanning telescopes using Holographic Optical Elements (HOEs) to reduce the size, mass, angular momentum, and cost of scanning lidar systems. NASA has developed two operating lidar systems based on 40 cm diameter HOEs. The first such system, named Prototype Holographic Atmospheric Scanner for Environmental Remote Sensing (PHASERS) was a joint development between NASA Goddard Space Flight Center (GSFC) and the University of Maryland College Park. PHASERS is based on a reflection HOE for use at the doubled Nd:YAG laser wavelength of 532 nm and has recently undergone a number of design changes in a collaborative effort between GSFC and Saint Anselm College in New Hampshire. The next step was to develop IR transmission HOEs for use with the Nd:YAG fundamental in the Holographic Airborne

  19. Near-infrared diffractive optical element (DOE) radiometer

    NASA Astrophysics Data System (ADS)

    Hamilton, Kelvin E.; Codere, J. R. Michel; Verreault, J. J. M.; Fjarlie, Earl J.

    1994-10-01

    A radiometer has been designed that operates at 1064 nanometers using a diffractive element arrangement to focus the energy onto a detector array. The aperture is made up of several elements consisting of both on and off-axis designed elements arranged to provide an overall FOV. The blur circle and the efficiency of the elements have been measured. The advantages of DOEs are weight saving, repetitiveness of design, the making of either off-axis or on-axis elements with the same ease, good efficiency of energy collection, and diffraction limited focusing.

  20. Laser Additive Melting and Solidification of Inconel 718: Finite Element Simulation and Experiment

    NASA Astrophysics Data System (ADS)

    Romano, John; Ladani, Leila; Sadowski, Magda

    2016-03-01

    The field of powdered metal additive manufacturing is experiencing a surge in public interest finding uses in aerospace, defense, and biomedical industries. The relative youth of the technology coupled with public interest makes the field a vibrant research topic. The authors have expanded upon previously published finite element models used to analyze the processing of novel engineering materials through the use of laser- and electron beam-based additive manufacturing. In this work, the authors present a model for simulating fabrication of Inconel 718 using laser melting processes. Thermal transport phenomena and melt pool geometries are discussed and validation against experimental findings is presented. After comparing experimental and simulation results, the authors present two correction correlations to transform the modeling results into meaningful predictions of actual laser melting melt pool geometries in Inconel 718.

  1. The Wavelet Element Method. Part 2; Realization and Additional Features in 2D and 3D

    NASA Technical Reports Server (NTRS)

    Canuto, Claudio; Tabacco, Anita; Urban, Karsten

    1998-01-01

    The Wavelet Element Method (WEM) provides a construction of multiresolution systems and biorthogonal wavelets on fairly general domains. These are split into subdomains that are mapped to a single reference hypercube. Tensor products of scaling functions and wavelets defined on the unit interval are used on the reference domain. By introducing appropriate matching conditions across the interelement boundaries, a globally continuous biorthogonal wavelet basis on the general domain is obtained. This construction does not uniquely define the basis functions but rather leaves some freedom for fulfilling additional features. In this paper we detail the general construction principle of the WEM to the 1D, 2D and 3D cases. We address additional features such as symmetry, vanishing moments and minimal support of the wavelet functions in each particular dimension. The construction is illustrated by using biorthogonal spline wavelets on the interval.

  2. Seawater-derived rare earth element addition to abyssal peridotites during serpentinization

    NASA Astrophysics Data System (ADS)

    Frisby, Carl; Bizimis, Michael; Mallick, Soumen

    2016-04-01

    Serpentinized abyssal peridotites are evidence for active communication between the Earth's hydrosphere and the upper mantle, where exchange and retention of both major and trace elements occur. Bulk rock Nd isotopes in serpentinized abyssal peridotites imply interaction of seawater with the peridotite. In contrast, the Nd isotopes of clinopyroxenes from serpentinized abyssal peridotites retain their primary magmatic signature. It is currently unclear if, how and where seawater-derived Nd and other REE are being added or exchanged with the mantle peridotite minerals during serpentinization. To remedy this knowledge gap, we present in situ trace and major element concentrations, bulk rock and sequential leaching experiment trace element concentrations as well as Nd, Sr isotope data on refertilized and depleted serpentinized abyssal peridotites from the Southwest Indian Ridge. The secondary serpentine matrix and magnetite veins in these peridotites have elevated LREE concentrations, with variable negative Ce anomalies and large Rb, Sr, Pb and U enrichments that resemble seawater trace element patterns. The LREE concentrations in the serpentine phase are higher than those expected for the primary mantle mineralogy (olivine, orthopyroxene) based on data from relic clinopyroxenes and equilibrium partition coefficients. These data are consistent with seawater-derived REE addition to the peridotite during serpentinization. The bulk rocks have more radiogenic Sr and more unradiogenic Nd isotopes than their clinopyroxene (up to 8 εNd units lower than clinopyroxene). Sequential leaching experiments designed to mobilize secondary carbonates and Fe-oxides show even more unradiogenic Nd isotope ratios in the leachates than the bulk rock and clinopyroxene, approaching seawater compositions (up to 15 εNd units lower than clinopyroxene). Mass balance calculations using trace elements or Nd isotopes suggest that up to 30% of the bulk peridotite Nd budget is of seawater origin and

  3. Simulation of Powder Layer Deposition in Additive Manufacturing Processes Using the Discrete Element Method

    SciTech Connect

    Herbold, E. B.; Walton, O.; Homel, M. A.

    2015-10-26

    This document serves as a final report to a small effort where several improvements were added to a LLNL code GEODYN-­L to develop Discrete Element Method (DEM) algorithms coupled to Lagrangian Finite Element (FE) solvers to investigate powder-­bed formation problems for additive manufacturing. The results from these simulations will be assessed for inclusion as the initial conditions for Direct Metal Laser Sintering (DMLS) simulations performed with ALE3D. The algorithms were written and performed on parallel computing platforms at LLNL. The total funding level was 3-­4 weeks of an FTE split amongst two staff scientists and one post-­doc. The DEM simulations emulated, as much as was feasible, the physical process of depositing a new layer of powder over a bed of existing powder. The DEM simulations utilized truncated size distributions spanning realistic size ranges with a size distribution profile consistent with realistic sample set. A minimum simulation sample size on the order of 40-­particles square by 10-­particles deep was utilized in these scoping studies in order to evaluate the potential effects of size segregation variation with distance displaced in front of a screed blade. A reasonable method for evaluating the problem was developed and validated. Several simulations were performed to show the viability of the approach. Future investigations will focus on running various simulations investigating powder particle sizing and screen geometries.

  4. Failure location prediction by finite element analysis for an additive manufactured mandible implant.

    PubMed

    Huo, Jinxing; Dérand, Per; Rännar, Lars-Erik; Hirsch, Jan-Michaél; Gamstedt, E Kristofer

    2015-09-01

    In order to reconstruct a patient with a bone defect in the mandible, a porous scaffold attached to a plate, both in a titanium alloy, was designed and manufactured using additive manufacturing. Regrettably, the implant fractured in vivo several months after surgery. The aim of this study was to investigate the failure of the implant and show a way of predicting the mechanical properties of the implant before surgery. All computed tomography data of the patient were preprocessed to remove metallic artefacts with metal deletion technique before mandible geometry reconstruction. The three-dimensional geometry of the patient's mandible was also reconstructed, and the implant was fixed to the bone model with screws in Mimics medical imaging software. A finite element model was established from the assembly of the mandible and the implant to study stresses developed during mastication. The stress distribution in the load-bearing plate was computed, and the location of main stress concentration in the plate was determined. Comparison between the fracture region and the location of the stress concentration shows that finite element analysis could serve as a tool for optimizing the design of mandible implants.

  5. CASCADES AFTER K-VACANCY PRODUCTION AND ADDITIONAL IONIZATION OR EXCITATION IN ATOMS OF LIGHT ELEMENTS

    SciTech Connect

    Kucas, S.; Momkauskaitė, A.; Karazija, R.

    2015-09-01

    The results of Auger and radiative cascades after the production of a vacancy in the K-shell and the additional ionization or excitation of the other shell are presented for the various ions of astrophysically important elements, namely, Ne, Mg, Si, S, and Ar. The detailed level-by-level calculations are performed using a single-configuration quasi-relativistic approximation. The populations of the levels of the excited configurations produced during a cascade as well as for the final ions are presented. These data enable us to take into account two-electron processes at the K-shell ionization, and thus to supplement the results of our earlier investigation of K-vacancy cascades.

  6. Microlithography application for production of multilevel diffractive optical elements (as a security hologram feature)

    NASA Astrophysics Data System (ADS)

    Braginets, Eugene; Kurashov, V.; Honcharuk, S.; Girnyk, V.; Kostyukevych, S.; Kostyukevych, K.

    2011-02-01

    The goal of a present research is to develop a method for production of multilevel Diffractive Optical Elements (DOEs) for use in Digital Security Holograms, using the direct-writing maskless lithography system.

  7. Nitrogen addition alters elemental stoichiometry within soil aggregates in a temperate steppe

    NASA Astrophysics Data System (ADS)

    Yin, Jinfei; Wang, Ruzhen; Liu, Heyong; Feng, Xue; Xu, Zhuwen; Jiang, Yong

    2016-11-01

    Ongoing increases in anthropogenic nitrogen (N) inputs have largely affected soil carbon (C) and nutrient cycling in most terrestrial ecosystems. Numerous studies have concerned the effects of elevated N inputs on soil dissolved organic carbon (DOC), dissolved inorganic N (DIN), available phosphorus (AP), exchangeable calcium (Ca) and magnesium (Mg), and available iron (Fe) and manganese (Mn). However, few have emphasized the stoichiometric traits of these soil parameters, especially within different soil aggregate fractions. In a semiarid grassland of Inner Mongolia, we studied the effect of N addition on the ratios of DOC : DIN, DOC : AP, DIN : AP, exchangeable Ca : Mg, available Fe : Mn within three soil aggregate classes of large macroaggregates (> 2000 µm), small macroaggregates (250-2000 µm), and microaggregates (< 250 µm). Elevated N inputs significantly decreased the DOC : DIN ratio within three soil aggregates. The soil DOC : AP ratio significantly decreased along with increasing N gradients within large macroaggregates and microaggregates. Nitrogen significantly decreased the ratio of exchangeable Ca : Mg within soil macroaggregates. The ratio of available Fe : Mn decreased with N addition within three soil aggregate classes. Alteration of elemental stoichiometry within soil fractions that are characterized by different nutrient retention capacity will influence the chemical composition of soil microorganisms and plant quality.

  8. Finite-element model for three-dimensional optical scattering problems.

    PubMed

    Wei, Xiuhong; Wachters, Arthur J; Urbach, H Paul

    2007-03-01

    We present a three-dimensional model based on the finite-element method for solving the time-harmonic Maxwell equation in optics. It applies to isotropic or anisotropic dielectrics and metals and to many configurations such as an isolated scatterer in a multilayer, bi-gratings, and crystals. We discuss the application of the model to near-field optical recording.

  9. Possibilities and limitations of space-variant holographic optical elements for switching networks and general interconnects

    NASA Astrophysics Data System (ADS)

    Schwider, Johannes; Stork, Wilhelm; Streibl, Norbert; Voelkel, Reinhard

    1990-07-01

    Optical interconnects of arbitrary design require space-variant optics. Planar holographic optical elements (HOE) offer a high flexibility and ease of production. HOE work via diffraction causing chromatic aberrations. This problem becomes serious if semiconductor lasers with poor wavelength stability should be used. Estimates for the number of independent space-variant interconnects their spatial tolerances and their wavelength stability will be considered. 1 . INTRODUC liON Optical interconnects enable the transmission of signals with ultra high frequencies with small crosstalk and rather low waste energy per transmission line. Two fields of application for optical wiring concepts can be discerned i. e. fixed pattern chip to chip (or board to board) interconnects and reconfigurable switching networks or bus systems where the interconnect path is selected out of a number of fixed interconnects by means of e. g. so-called exchange bypass modules (EBM)1''2. 2. INTERCONNECT CONCEPTS A general feature of optical interconnects is the fact that the light has to leave the board/chip-plane in order to give room for the interconnect fabric i. e. the light leaves the board-plane perpendicularly The necessary optical means are: collimating or focussing elements deflectors and beamsplitters(fanout). Gratings or more general holograms seem the most promising optical elements. These elements may be planar and can be configurated in an arbitrary manner. HOE3 can be used for the above mentioned purposes . Efficient HOE can be obtained either by using thick

  10. Multipoint photonic doppler velocimetry using optical lens elements

    DOEpatents

    Frogget, Brent Copely; Romero, Vincent Todd

    2014-04-29

    A probe including a fisheye lens is disclosed to measure the velocity distribution of a moving surface along many lines of sight. Laser light, directed to the surface and then reflected back from the surface, is Doppler shifted by the moving surface, collected into fisheye lens, and then directed to detection equipment through optic fibers. The received light is mixed with reference laser light and using photonic Doppler velocimetry, a continuous time record of the surface movement is obtained. An array of single-mode optical fibers provides an optic signal to an index-matching lens and eventually to a fisheye lens. The fiber array flat polished and coupled to the index-matching lens using index-matching gel. Numerous fibers in a fiber array project numerous rays through the fisheye lens which in turn project many measurement points at numerous different locations to establish surface coverage over a hemispherical shape with very little crosstalk.

  11. Chromatic error correction of diffractive optical elements at minimum etch depths

    NASA Astrophysics Data System (ADS)

    Barth, Jochen; Gühne, Tobias

    2014-09-01

    The integration of diffractive optical elements (DOE) into an optical design opens up new possibilities for applications in sensing and illumination. If the resulting optics is used in a larger spectral range we must correct not only the chromatic error of the conventional, refractive, part of the design but also of the DOE. We present a simple but effective strategy to select substrates which allow the minimum etch depths for the DOEs. The selection depends on both the refractive index and the dispersion.

  12. Optical elements formed by compressed gases: Analysis and potential applications

    NASA Technical Reports Server (NTRS)

    Howes, W. L.

    1986-01-01

    Spherical, cylindrical, and conical shock waves are optically analogous to gas lenses. The geometrical optics of these shock configurations are analyzed as they pertain to flow visualization instruments, particularly the rainbow schlieren apparatus and single-pass interferometers. It is proposed that a lens or mirror formed by gas compressed between plastic sheets has potential as a fluid visualization test object; as the objective mirror in a very large space-based telescope, communication antenna, or energy collector; as the objective mirror in inexpensive commercial telescopes; and as a component in fluid visualization apparatuses.

  13. Dual focus diffractive optical element with extended depth of focus

    NASA Astrophysics Data System (ADS)

    Uno, Katsuhiro; Shimizu, Isao

    2014-09-01

    A dual focus property and an extended depth of focus were verified by a new type of diffractive lens displaying on liquid crystal on silicon (LCoS) devices. This type of lens is useful to read information on multilayer optical discs and tilted discs. The radial undulation of the phase groove on the diffractive lens gave the dual focus nature. The focal extension was performed by combining the dual focus lens with the axilens that was invented for expanding the depth of focus. The number of undulations did not affect the intensity along the optical axis but the central spot of the diffraction pattern.

  14. Effects of heavy metal and other elemental additives to activated sludge on growth of Eisenia foetida

    SciTech Connect

    Hartenstein, R.; Neuhauser, E.F.; Narahara, A.

    1981-09-01

    The approximate level at which added concentrations of certain elements would cause an activated sludge to induce a toxic effect upon the growth of Eisenia foetida was determined. During 43 trials on sludge samples obtained throughout 1 year of study, earthworms grew from 3 to 10 mg live wt at hatching to 792 mg +- 18% (mean +- C.V.) in 8 weeks, when sludge was 24/sup 0/C and contained no additives. None of several elements commonly used in microbial growth media enhanced the growth rate of the earthworm. At salt concentrations up to about 6.6% on a dry wt basis, none of six anions tested was in and of itself toxic, while five of 15 cations - Co, Hg, Cu, Ni, and Cd - appeared specifically to inhibit growth rate or cause death. Manganese, Cr, and Pb were innocuous even at the highest levels of application - 22,000, 46,000, and 52,000 mg/kg, respectively. Neither the anionic nor cationic component of certain salts, such as NaCl or NH/sub 4/Cl, could be said to inhibit growth, which occurred only at high concentrations of these salts (about 3.3 and/or 6.6%). Below 7 mmho/cm, toxicity could not be correlated with electrolytic conductance, though higher values may help to explain the nonspecific growth inhibitory effects of salts like NaCl and KCl. Nor could toxicity ever be ascribed to hydrogen ion activity, since sludge pH was not altered even at the highest salt dose. It is concluded that except under very extreme conditions, the levels of heavy metals and salts generally found in activated sludges will not have an adverse affect on the growth of E. foetida.

  15. Effect of additional optical pumping injection into the ground-state ensemble on the gain and the phase recovery acceleration of quantum-dot semiconductor optical amplifiers

    NASA Astrophysics Data System (ADS)

    Kim, Jungho

    2014-02-01

    The effect of additional optical pumping injection into the ground-state ensemble on the ultrafast gain and the phase recovery dynamics of electrically-driven quantum-dot semiconductor optical amplifiers is numerically investigated by solving 1088 coupled rate equations. The ultrafast gain and the phase recovery responses are calculated with respect to the additional optical pumping power. Increasing the additional optical pumping power can significantly accelerate the ultrafast phase recovery, which cannot be done by increasing the injection current density.

  16. MANN: A program to transfer designs for diffractive optical elements to a MANN photolithographic mask generator

    NASA Technical Reports Server (NTRS)

    Matthys, Donald R.

    1994-01-01

    There are two basic areas of interest for diffractive optics. In the first, the property of wavefront division is exploited for achieving optical fanout, analogous to the more familiar electrical fanout of electronic circuitry. The basic problem here is that when using a simple uniform diffraction grating the energy input is divided unevenly among the output beams. The other area of interest is the use of diffractive elements to replace or supplement standard refractive elements such as lenses. Again, local grating variations can be used to control the amount of bending imparted to optical rays, and the efficiency of the diffractive element will depend on how closely the element can be matched to the design requirements. In general, production restrictions limit how closely the element approaches the design, and for the common case of photolithographic production, a series of binary masks is required to achieve high efficiency. The actual design process is much more involved than in the case of elements for optical fanout, as the desired phase of the optical wavefront over some reference plane must be specified and the phase alteration to be introduced at each point by the diffraction element must be known. This generally requires the utilization of a standard optical design program. Two approaches are possible. In the first approach, the diffractive element is treated as a special type of lens and the ordinary optical design equations are used. Optical design programs tend to follow a second approach, namely, using the equations of optical interference derived from holographic theory and then allowing the introduction of phase front corrections in the form of polynomial equations. By using either of these two methods, diffractive elements can be used not only to compensate for distortions such as chromatic or spherical aberration, but also to perform the work of a variety of other optical elements such as null correctors, beam shapers, etc. The main focus of the

  17. Cryogenic optical test planning using the Optical Telescope Element Simulator with the James Webb Space Telescope Integrated Science Instrument Module

    NASA Astrophysics Data System (ADS)

    Reichard, Timothy A.; Bond, Nicholas A.; Greeley, Bradford W.; Malumuth, Eliot M.; Melendez, Marcio; Shiri, Ron; Alves de Oliveira, Catarina; Antonille, Scott R.; Birkmann, Stephan; Davis, Clinton; Dixon, William V.; Martel, André R.; Miskey, Cherie L.; Ohl, Raymond G.; Sabatke, Derek; Sullivan, Joseph

    2016-09-01

    NASA's James Webb Space Telescope (JWST) is a 6.5 m diameter, segmented, deployable telescope for cryogenic infrared space astronomy ( 40 K). The JWST Observatory architecture includes the Optical Telescope Element (OTE) and the Integrated Science Instrument Module (ISIM) element that contains four science instruments (SIs), including a guider. The SI and guider units are integrated to the ISIM structure and optically tested at NASA Goddard Space Flight Center as an instrument suite using a telescope simulator (Optical Telescope Element SIMulator; OSIM). OSIM is a high-fidelity, cryogenic JWST telescope simulator that features a 1.5m diameter powered mirror. The SIs are aligned to the flight structure's coordinate system under ambient, clean room conditions using optomechanical metrology and customized interfaces. OSIM is aligned to the ISIM mechanical coordinate system at the cryogenic operating temperature via internal mechanisms and feedback from alignment sensors and metrology in six degrees of freedom. SI performance, including focus, pupil shear, pupil roll, boresight, wavefront error, and image quality, is evaluated at the operating temperature using OSIM. The comprehensive optical test plans include drafting OSIM source configurations for thousands of exposures ahead of the start of a cryogenic test campaign. We describe how we predicted the performance of OSIM light sources illuminating the ISIM detectors to aide in drafting these optical tests before a test campaign began. We also discuss the actual challenges and successes of those exposure predictions encountered during a test campaign to fulfill the demands of the ISIM optical performance verification.

  18. Elements for hard X-ray optics produced by cryogenic plasma etching of silicon

    NASA Astrophysics Data System (ADS)

    Miakonkikh, Andrey V.; Rogozhin, Alexander E.; Rudenko, Konstantin V.; Lukichev, Vladimir F.; Yunkin, Vyacheslav A.; Snigirev, Anatoly A.

    2016-12-01

    A number of different hard X-ray optics elements such as refractive lenses, refractive bi-lenses and multilens interferometers, mirror interferometers can be made of Silicon. The optical performance of these elements depends on the quality of refracting and reflecting surfaces. Cryogenic deep anisotropic etching was proposed for fabrication of parabolic planar lenses and mirror interferometers. The investigation of sidewall roughness was done by AFM and by optical interferometry. Geometrical parameters of structures were measured by SEM. It was observed that roughness of inner sidewalls of etched structures does not exceed 3 nm/um (RMS) and deviation from vertical profile was within 30 nm along 20 um depth.

  19. Extension to linear dynamics for hybrid stress finite element formulation based on additional displacements

    NASA Astrophysics Data System (ADS)

    Sumihara, K.

    Based upon legitimate variational principles, one microscopic-macroscopic finite element formulation for linear dynamics is presented by Hybrid Stress Finite Element Method. The microscopic application of Geometric Perturbation introduced by Pian and the introduction of infinitesimal limit core element (Baby Element) have been consistently combined according to the flexible and inherent interpretation of the legitimate variational principles initially originated by Pian and Tong. The conceptual development based upon Hybrid Finite Element Method is extended to linear dynamics with the introduction of physically meaningful higher modes.

  20. Application of fluidic lens technology to an adaptive holographic optical element see-through autophoropter

    NASA Astrophysics Data System (ADS)

    Chancy, Carl H.

    A device for performing an objective eye exam has been developed to automatically determine ophthalmic prescriptions. The closed loop fluidic auto-phoropter has been designed, modeled, fabricated and tested for the automatic measurement and correction of a patient's prescriptions. The adaptive phoropter is designed through the combination of a spherical-powered fluidic lens and two cylindrical fluidic lenses that are orientated 45o relative to each other. In addition, the system incorporates Shack-Hartmann wavefront sensing technology to identify the eye's wavefront error and corresponding prescription. Using the wavefront error information, the fluidic auto-phoropter nulls the eye's lower order wavefront error by applying the appropriate volumes to the fluidic lenses. The combination of the Shack-Hartmann wavefront sensor the fluidic auto-phoropter allows for the identification and control of spherical refractive error, as well as cylinder error and axis; thus, creating a truly automated refractometer and corrective system. The fluidic auto-phoropter is capable of correcting defocus error ranging from -20D to 20D and astigmatism from -10D to 10D. The transmissive see-through design allows for the observation of natural scenes through the system at varying object planes with no additional imaging optics in the patient's line of sight. In this research, two generations of the fluidic auto-phoropter are designed and tested; the first generation uses traditional glass optics for the measurement channel. The second generation of the fluidic auto-phoropter takes advantage of the progress in the development of holographic optical elements (HOEs) to replace all the traditional glass optics. The addition of the HOEs has enabled the development of a more compact, inexpensive and easily reproducible system without compromising its performance. Additionally, the fluidic lenses were tested during a National Aeronautics Space Administration (NASA) parabolic flight campaign, to

  1. Plasma etching antireflection nanostructures on optical elements in concentrator photovoltaic systems

    NASA Astrophysics Data System (ADS)

    Tamayo Ruiz, Efrain Eduardo; Watanabe, Kentaroh; Tamaki, Ryo; Hoshii, Takuya; Sugiyama, Masakazu; Okada, Yoshitaka; Miyano, Kenjiro; Cvetkovic, Aleksandra; Mohedano, Rubén; Hernandez, Maikel

    2015-01-01

    Transmission-type concentrator photovoltaic (CPV) systems are a potential candidate to achieve high efficiency and low cost solar energy. The use of optical elements in these systems creates reflection losses of incoming solar energy that account for about 8% to 12% depending on the optical design. In order to reduce these losses, we have nanostructured the air/optical-elements' interfaces by using plasma etching methods on the Fresnel lens made of poly(methyl methacrylate) (PMMA) and the homogenizer made of glass. On flat PMMA and glass substrates, transmittance enhancement measurements are in agreement with relative Jsc gains. The field test results using a CPV module with all textured optical-elements' interfaces achieved 8.0% and 4.3% relative Jsc and efficiency gains, respectively, demonstrating the potential of this approach to tackle the reflection losses.

  2. The Optical Telescope Element Simulator for the James Webb Space Telescope

    NASA Astrophysics Data System (ADS)

    Davila, Pamela S.; Bos, Brent J.; Cheng, Edward S.; Chang, Bill; Eichhorn, William L.; Frey, Bradley J.; Garza, Mario; Gong, Qian; Greeley, Bradford W.; Guzek, Jeff; Hakun, Claef F.; Hovmand, Lars; Kirk, Jeff; Kubalak, David A.; Leviton, Douglas; Nagle, Adrian; Nyquist, Rich; Pham, Thai; Robinson, F. David; Sabatke, Derek; Sullivan, Joseph F.; Volmer, Paul; VonHandorf, Rob; Youngworth, Richard N.

    2008-07-01

    The James Webb Space Telescope Observatory will consist of three flight elements: (1) the Optical Telescope Element (OTE), (2) the Integrated Science Instrument Module Element (ISIM), and (3) the Spacecraft Element. The ISIM element consists of a composite bench structure that uses kinematic mounts to interface to each of the optical benches of the three science instruments and the guider. The ISIM is also kinematically mounted to the telescope primary mirror structure. An enclosure surrounds the ISIM structure, isolates the ISIM region thermally from the other thermal regions of the Observatory, and serves as a radiator for the science instruments and guider. Cryogenic optical testing of the ISIM Structure and the Science Instruments will be conducted at Goddard Space Flight Center using an optical telescope simulator that is being developed by a team from Ball Aerospace and Goddard Space Flight Center, and other local contractors. This simulator will be used to verify the performance of the ISIM element before delivery to the Northup Grumman team for integration with the OTE. In this paper, we describe the O OTE Sim TE Simulator (OSIM) and provide a brief overview of the optical test program. ulator

  3. Recent development in light Ultramicroscopy using aspherical optical elements

    NASA Astrophysics Data System (ADS)

    Saghafi, Saiedeh; Becker, Klaus; Hahn, Christian; Dodt, Hans-Ulrich

    2012-12-01

    Here we present a new light sheet generator unit for Ultramicroscopy (UM) employing a combination of optical lenses with aspherical surface structure. UM allows 3D-vizualization of chemically transparent biological specimens with μm-resolution. Improving optical characteristics parameters of light sheet such as the uniformity factor of spatial intensity distribution along the line of focus, the thickness of light sheet, and chromatic aberrations are the most important criteria in this design. Since we do not use any hard edge aperture there is no truncation of the beam and laser energy is used more efficiently. Due to these improvements, a marked enhancement in presenting fine details of biological specimens such as Drosophila melanogaster, entire mouse brain, and hippocampus are achieved.

  4. James Webb Space Telescope Optical Telescope Element/Integrated Science Instrument Module (OTIS) Status

    NASA Technical Reports Server (NTRS)

    Feinberg, Lee; Voyton, Mark; Lander, Juli; Keski-Kuha, Ritva; Matthews, Gary

    2016-01-01

    The James Webb Space Telescope Optical Telescope Element (OTE) and Integrated Science Instrument Module (ISIM) are integrated together to form the OTIS. Once integrated, the OTIS undergoes primary mirror center of curvature optical tests, electrical and operational tests, acoustics and vibration testing at the Goddard Space Flight Center before being shipped to the Johnson Space Center for cryogenic optical testing of the OTIS. In preparation for the cryogenic optical testing, the JWST project has built a Pathfinder telescope and has completed two Optical Ground System Equipment (OGSE) cryogenic optical tests with the Pathfinder. In this paper, we will summarize optical test results to date and status the final Pathfinder test and the OTIS integration and environmental test preparations

  5. Holographic Optical Elements with Ultra-High Spatial Frequencies.

    DTIC Science & Technology

    1983-01-01

    capable of solving most of these problems. Holography Wavefront reconstruction, now known as holography, was invented by Dennis Gabor in 194821. At...Zone Plate. How- ever, it was not until Gabor proposed his principle of wave- front reconstruction and Leith and Upatnieks introduced off-axis... Gabor , Nature 161, 777 (1948). 22. J. W. Goodman, Introduction to Fourier Optics, McGraw- Hill Book Company, St. Louis,MI (1968). 23. R. J. Collier, C. B

  6. Simple, monolithic optical element for forward-viewing spectrally encoded endoscopy (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Do, Dukho; Kang, Dongkyun; Ikuta, Mitsuhiro; Tearney, Guillermo J.

    2016-03-01

    Spectrally encoded endoscopy (SEE) is a miniature endoscopic technology that can acquire images of internal organs through a hair-thin probe. While most previously described SEE probes have been side viewing, forward-view (FV)-SEE is advantageous in certain clinical applications as it provides more natural navigation of the probe and has the potential to provide a wider field of view. Prior implementations of FV-SEE used multiple optical elements that increase fabrication complexity and may diminish the robustness of the device. In this paper, we present a new design that uses a monolithic optical element to realize FV-SEE imaging. The optical element is specially designed spacer, fabricated from a 500-μm-glass rod that has a mirror surface on one side and a grating stamped on its distal end. The mirror surface is used to change the incident angle on the grating to diffract the shortest wavelength of the spectrum so that it is parallel to the optical axis. Rotating the SEE optics creates a circular FV-SEE image. Custom-designed software processes FV-SEE images into circular images, which are displayed in real-time. In order to demonstrate this new design, we have constructed the FV-SEE optical element using a 1379 lines/mm diffraction grating. When illuminated with a source with a spectral bandwidth of 420-820 nm, the FV-SEE optical element provides 678 resolvable points per line. The imaging performance of the FV-SEE device was tested by imaging a USAF resolution target. SEE images showed that this new approach generates high quality images in the forward field with a field of view of 58°. Results from this preliminary study demonstrate that we can realize FV-SEE imaging with simple, monolithic, miniature optical element. The characteristics of this FV-SEE configuration will facilitate the development of robust miniature endoscopes for a variety of medical imaging applications.

  7. Addition of organic amendments contributes to C sequestration in trace element contaminated soils.

    NASA Astrophysics Data System (ADS)

    del Mar Montiel Rozas, María; Panettier, Marco; Madejón Rodríguez, Paula; Madejón Rodríguez, Engracia

    2015-04-01

    Nowadays, the study of global C cycle and the different natural sinks of C have become especially important in a climate change context. Fluxes of C have been modified by anthropogenic activities and, presently, the global objective is the decrease of net CO2 emission. For this purpose, many studies are being conducted at local level for evaluate different C sequestration strategies. These techniques must be, in addition to safe in the long term, environmentally friendly. Restoration of contaminated and degraded areas is considered as a strategy for SOC sequestration. Our study has been carried out in the Guadiamar Green Corridor (Seville, Spain) affected by the Aznalcóllar mining accident. This accident occurred 16 years ago, due to the failure of the tailing dam which contained 4-5 million m3 of toxic tailings (slurry and acid water).The affected soils had a layer of toxic sludge containing heavy metals as As, Cd, Cu, Pb and Zn. Restoration techniques began to be applied just after the accident, including the removal of the toxic sludge and a variable layer of topsoil (10-30 cm) from the surface. In a second phase, in a specific area (experimental area) of the Green Corridor the addition of organic amendments (Biosolid compost (BC) and Leonardite (LE), a low grade coal rich in humic acids) was carried out to increase pH, organic matter and fertility in a soil which lost its richest layer during the clean-up operation. In our experimental area, half of the plots (A) received amendments for four years (2002, 2003, 2006 and 2007) whereas the other half (B) received amendments only for two years (2002-2003). To compare, plots without amendments were also established. Net balance of C was carried out using values of Water Soluble Carbon (WSC) and Total Organic Carbon (TOC) for three years (2012, 2013 and 2015). To eliminate artificial changes carried out in the plots, amendment addition and withdrawal of biomass were taken into account to calculate balance of kg TOC

  8. Reducing aberration effect of Fourier transform lens by modifying Fourier spectrum of diffractive optical element in beam shaping optical system.

    PubMed

    Zhang, Fang; Zhu, Jing; Song, Qiang; Yue, Weirui; Liu, Jingdan; Wang, Jian; Situ, Guohai; Huang, Huijie

    2015-10-20

    In general, Fourier transform lenses are considered as ideal in the design algorithms of diffractive optical elements (DOEs). However, the inherent aberrations of a real Fourier transform lens disturb the far field pattern. The difference between the generated pattern and the expected design will impact the system performance. Therefore, a method for modifying the Fourier spectrum of DOEs without introducing other optical elements to reduce the aberration effect of the Fourier transform lens is proposed. By applying this method, beam shaping performance is improved markedly for the optical system with a real Fourier transform lens. The experiments carried out with a commercial Fourier transform lens give evidence for this method. The method is capable of reducing the system complexity as well as improving its performance.

  9. Micromilled optical elements for edge-lit illumination panels

    NASA Astrophysics Data System (ADS)

    Ronny, Rahima Afrose; Knopf, George K.; Bordatchev, Evgueni; Nikumb, Suwas

    2013-04-01

    Edge-lit light guide panels (LGPs) with micropatterned surfaces represent a new technology for developing small- and medium-sized illumination sources for application such as automotive, residential lighting, and advertising displays. The shape, density, and spatial distribution of the micro-optical structures (MOSs) imprinted on the transparent LGP must be selected to achieve high brightness and uniform luminance over the active surface. We examine how round-tip cylindrical MOSs fabricated by precision micromilling can be used to create patterned surfaces on low-cost transparent polymethyl-methacrylate substrates for high-intensity illumination applications. The impact of varying the number, pitch, spatial distribution, and depth of the optical microstructures on lighting performance is initially investigated using LightTools™ simulation software. To illustrate the microfabrication process, several 100×100×6 mm3 LGP prototypes are constructed and tested. The prototypes include an "optimized" array of MOSs that exhibit near-uniform illumination (approximately 89%) across its active light-emitting surface. Although the average illumination was 7.3% less than the value predicted from numerical simulation, it demonstrates how LGPs can be created using micromilling operations. Customized MOS arrays with a bright rectangular pattern near the center of the panel and a sequence of MOSs that illuminate a predefined logo are also presented.

  10. GRIN optics with transition elements in gel-silica matrices

    NASA Astrophysics Data System (ADS)

    Kunetz, James M.; West, Jon K.; Hench, Larry L.

    1992-12-01

    Sol-gel technology is providing a viable alternative path towards developing doped optical components via impregnation of Type VI gel silica using a vapor or liquid phase. Past work presented an optical technique for determining quantitative mass transport properties of Cr3+ ions within the water filled porous phase of Type VI silica. Ion influx is measured by integrating the strong absorption bands produced by the chromium in the visible region. Diffusion coefficients are determined for an array of pore properties (radius, volume, surface area) as well as solution concentrations. Diffusion coefficients are calculated to be 2.0 X 10-8 cm2/sec for the most restricted case and approach 1.6 X 10-6 cm2/sec, the bulk liquid diffusion coefficient, as the ratio of diffusing solute diameter to the pore diameter decreases. Final chromium distributions are determined using electron microprobe x-ray. Higher chromium distributions are found on surfaces of the gels from which solvent is restricted from evaporating. Sample geometries affect the percent change of concentration across the cross-section.

  11. Orbital Element Generation for an Optical and Laser Tracking Space Object Catalogue

    NASA Astrophysics Data System (ADS)

    Bennett, J.; Smith, C.; Greene, B.; Kucharski, D.; Sang, J.

    In this paper results are presented from an analysis assessing the data requirements for orbit element generation for a new high-accuracy catalogue for the Space Environment Research Centre, Australia. The analysis is dedicated to obtaining a robust set of rules for orbit element generation using orbital data from optical and laser tracking of debris and satellites. Optical and laser tracking data collected from several tracking campaigns carried out by EOS Space Systems, located on Mount Stromlo, Australia, is fitted to provide an updated orbital element. The element accuracy is determined for various data-availability scenarios, including: (1) fitting optical tracking data only; (2) fitting laser range data only; (3) fitting optical and laser tracking data. The orbit predictions from the new orbital element are compared with SGP4 propagation from two-line element data and accuracy is assessed by comparing with high accuracy ephemerides where available or subsequent accurate tracking data. The application of the catalogue to conjunction analyses is also discussed. This work forms part of the collaborative effort of the Space Environment Management Cooperative Research Centre which is developing new technologies and strategies to preserve the space environment (www.serc.org.au).

  12. A high-accuracy optical linear algebra processor for finite element applications

    NASA Technical Reports Server (NTRS)

    Casasent, D.; Taylor, B. K.

    1984-01-01

    Optical linear processors are computationally efficient computers for solving matrix-matrix and matrix-vector oriented problems. Optical system errors limit their dynamic range to 30-40 dB, which limits their accuray to 9-12 bits. Large problems, such as the finite element problem in structural mechanics (with tens or hundreds of thousands of variables) which can exploit the speed of optical processors, require the 32 bit accuracy obtainable from digital machines. To obtain this required 32 bit accuracy with an optical processor, the data can be digitally encoded, thereby reducing the dynamic range requirements of the optical system (i.e., decreasing the effect of optical errors on the data) while providing increased accuracy. This report describes a new digitally encoded optical linear algebra processor architecture for solving finite element and banded matrix-vector problems. A linear static plate bending case study is described which quantities the processor requirements. Multiplication by digital convolution is explained, and the digitally encoded optical processor architecture is advanced.

  13. Non-contact high precision measurement of surface form tolerances and central thickness for optical elements

    NASA Astrophysics Data System (ADS)

    Lou, Ying

    2010-10-01

    The traditional contact measuring methods could not satisfy the current optical elements measuring requirements. Noncontact high precision measuring theory, principle and instrument of the surface form tolerances and central thickness for optical elements were studied in the paper. In comparison with other types of interferometers, such as Twyman-Green and Mach-Zehnder, a Fizeau interferometer has the advantages of having fewer optical components, greater accuracy, and is easier to use. Some relations among the 3/A(B/C), POWER/PV and N/ΔN were studied. The PV with POWER removed can be the reference number of ΔN. The chromatic longitudinal aberration of a special optical probe can be used for non-contanct central thickness measurement.

  14. Iterative Fourier transform algorithm with regularization for the optimal design of diffractive optical elements.

    PubMed

    Kim, Hwi; Yang, Byungchoon; Lee, Byoungho

    2004-12-01

    There is a trade-off between uniformity and diffraction efficiency in the design of diffractive optical elements. It is caused by the inherent ill-posedness of the design problem itself. For the optimal design, the optimum trade-off needs to be obtained. The trade-off between uniformity and diffraction efficiency in the design of diffractive optical elements is theoretically investigated based on the Tikhonov regularization theory. A novel scheme of an iterative Fourier transform algorithm with regularization to obtain the optimum trade-off is proposed.

  15. Hydrophobic optical elements for near-field optical analysis (NOA) in liquid environment--a preliminary study.

    PubMed

    Sommer, A P; Franke, R-P

    2002-01-01

    Near-field Scanning Optical Microscopy (NSOM) in liquid environment is expected to allow time resolved morphological mappings on cellular surfaces on the nanoscale level. Near-field Optical Analysis (NOA) via NSOM exploits the energy transfer from the tip of an optical element (tip diameter > or = 20nm), oscillating within the range of the characteristic length of the energy transfer ( approximately 10nm) in the near-field of the surface to be analysed. In NOA, a molecular assembly is monitored by visible light with a resolution far below the wavelength of visible light. Actually, NOA is successfully applied in mapping local optical contrasts, for instance in photonic crystals with dielectric periodicities on the nanoscale. NSOM could in principle be performed in two different modes: tapping mode, with tip-oscillations perpendicular, or shear force mode, with tip-oscillations parallel to the substrate. Both basic modes have specific advantages and disadvantages. In biological systems (e.g. in cell cultures), where scanning in liquids is prevalent, elongated optical elements non-invasively operated in the shear force modus could have some specific advantages when compared to contact modus systems. While tapping mode NSOM provides satisfactory nanoscale images even on solid surfaces covered with millimetres of liquids, the performance of shear force mode NSOM is presently largely confined to operations on dry samples. This is due to the inability of conventional shear force mode NSOM systems to provide sharp topographic images of sample surfaces substantially covered with liquids. By equipping a conventional NSOM system with hydrophobic optical elements, shear force mode based topographic images could be obtained on biological samples in dry as well as in aqueous environment, and with resolutions on the nanoscale level.

  16. Challenges in mold manufacturing for high precision molded diffractive optical elements

    NASA Astrophysics Data System (ADS)

    Pongs, Guido; Bresseler, Bernd; Schweizer, Klaus; Bergs, Thomas

    2016-09-01

    Isothermal precision glass molding of imaging optics is the key technology for mass production of precise optical elements. Especially for numerous consumer applications (e.g. digital cameras, smart phones, …), high precision glass molding is applied for the manufacturing of aspherical lenses. The usage of diffractive optical elements (DOEs) can help to further reduce the number of lenses in the optical systems which will lead to a reduced weight of hand-held optical devices. But today the application of molded glass DOEs is limited due to the technological challenges in structuring the mold surfaces. Depending on the application submicrometer structures are required on the mold surface. Furthermore these structures have to be replicated very precisely to the glass lens surface. Especially the micro structuring of hard and brittle mold materials such as Tungsten Carbide is very difficult and not established. Thus a multitude of innovative approaches using diffractive optical elements cannot be realized. Aixtooling has investigated in different mold materials and different suitable machining technologies for the micro- and sub-micrometer structuring of mold surfaces. The focus of the work lays on ultra-precision grinding to generate the diffractive pattern on the mold surfaces. This paper presents the latest achievements in diffractive structuring of Tungsten Carbide mold surfaces by ultra-precision grinding.

  17. Alleviation of additional phase noise in fiber optical parametric amplifier based signal regenerator.

    PubMed

    Jin, Lei; Xu, Bo; Yamashita, Shinji

    2012-11-19

    We theoretically and numerically explain the power saturation and the additional phase noise brought by the fiber optical parametric amplifier (FOPA). An equation to calculate an approximation to the saturated signal output power is presented. We also propose a scheme for alleviating the phase noise brought by the FOPA at the saturated state. In simulation, by controlling the decisive factor dispersion difference term Δk of the FOPA, amplitude-noise and additional phase noise reduction of quadrature phase shift keying (QPSK) based on the saturated FOPA is studied, which can provide promising performance to deal with PSK signals.

  18. The effect of trace element addition to mono-digestion of grass silage at high organic loading rates.

    PubMed

    Wall, David M; Allen, Eoin; Straccialini, Barbara; O'Kiely, Padraig; Murphy, Jerry D

    2014-11-01

    This study investigated the effect of trace element addition to mono-digestion of grass silage at high organic loading rates. Two continuous reactors were compared. The first mono-digested grass silage whilst the second operated in co-digestion, 80% grass silage with 20% dairy slurry (VS basis). The reactors were run for 65weeks with a further 5weeks taken for trace element supplementation for the mono-digestion of grass silage. The co-digestion reactor reported a higher biomethane efficiency (1.01) than mono-digestion (0.90) at an OLR of 4.0kgVSm(-3)d(-1) prior to addition of trace elements. Addition of cobalt, iron and nickel, led to an increase in the SMY in mono-digestion of grass silage by 12% to 404LCH4kg(-1)VS and attained a biomethane efficiency of 1.01.

  19. Polarization selecting optical element using a porro prism incorporating a thin film polarizer in a single element

    SciTech Connect

    Hendrix, James Lee

    2001-05-08

    A Porro prism and a light polarizer are combined in a single optical element termed a Hendrix Prism. The design provides retro-reflection of incoming light of a predetermined polarization in a direction anti-parallel to the direction of light incidence, while reflecting undesired light, i.e., that having a polarization orthogonal to the predetermined polarization, from the surface of the light polarizer. The undesired light is reflected in a direction that does not interfere with the intended operation of the device in which the Hendrix Prism is installed yet provides feedback to the system in which it is used.

  20. Polarization selecting Optical Element using a Porro Prism Incorporating a thin film Polarizer in a single element

    SciTech Connect

    Hendrix, James lee

    2000-01-28

    A Porro prism and a light polarizer are combined in a single optical element termed a Hendrix Prism. The design provides retro-reflection of incoming light of a predetermined polarization in a direction anti-parallel to the direction of light incidence, while reflecting undesired light, i.e., that having a polarization orthogonal to the predetermined polarization, from the surface of the light polarizer. The undesired light is reflected in a direction that does not interfere with the intended operation of the device in which the Hendrix Prism is installed yet provides feedback to the system in which it is used.

  1. Implementation of ordinary and extraordinary beams interference by application of diffractive optical elements

    NASA Astrophysics Data System (ADS)

    Khonina, S. N.; Karpeev, S. V.; Morozov, A. A.; Paranin, V. D.

    2016-07-01

    We apply diffractive optical elements in problems of transformation of Bessel beams in a birefringent crystal. Using plane waves expansion we show a significant interference between the ordinary and extraordinary beams due to the energy transfer in the orthogonal transverse components in the nonparaxial mode. A comparative analysis of the merits and lack of diffractive and refractive axicons in problems of formation non-paraxial Bessel beams has shown the preferability of diffractive optics application in crystal optics. The transformation of uniformly polarised Bessel beams in the crystal of Iceland spar in the nonparaxial mode by application of a diffractive axicon is investigated numerically and experimentally.

  2. Directly laser-written integrated photonics devices including diffractive optical elements

    NASA Astrophysics Data System (ADS)

    Choi, Jiyeon; Ramme, Mark; Richardson, Martin

    2016-08-01

    Femtosecond laser-written integrated devices involving Fresnel Zone Plates (FZPs) and waveguide arrays are demonstrated as built-in optical couplers. These structures were fabricated in borosilicate glass using a direct laser writing technique. The optical properties of these integrated photonic structures were investigated using CW lasers and high-resolution CCDs. For a single FZP coupled to a single waveguide, the overall coupling efficiency was 9%. A multiplexed optical coupler composed of three FZP layers was demonstrated to couple three waveguides simultaneously in a waveguide array. Structures of this type can be used as platforms for multichannel waveguide coupling elements or as microfluidic sensors that require higher light collecting efficiency.

  3. Hard protective waterproof coating for high-power laser optical elements.

    PubMed

    Murahara, Masataka; Sato, Nobuhiro; Ikadai, Akimitsu

    2005-12-15

    We developed a new method for making a waterproof coating by photooxidation of silicone oil. The silicone oil was spin coated onto the surfaces of optical elements, i.e., a plastic lens, a laser mirror, and a nonlinear optical crystal, and then irradiated with a xenon excimer lamp in air, which transformed the organic silicone oil into an amorphous glass film. This technique has enabled an optical thin film to transmit ultraviolet rays of wavelengths below 200 nm and to exhibit the characteristics of homogeneity, high density, and resistance to environmental effects and to corrosion by water, and a Mohs scale value of 5.

  4. Optically imprinted reconfigurable photonic elements in a VO{sub 2} nanocomposite

    SciTech Connect

    Jostmeier, Thorben; Betz, Markus; Zimmer, Johannes; Krenner, Hubert J.; Karl, Helmut

    2014-08-18

    We investigate the optical and thermal hysteresis of single-domain vanadium dioxide nanocrystals fabricated by ion beam synthesis in a fused silica matrix. The nanocrystals exhibit a giant hysteresis, which permits to optically generate a long-time stable supercooled metallic phase persistent down to practically room temperature. Spatial patterns of supercooled and insulating nanocrystals feature a large dielectric contrast, in particular, for telecom wavelengths. We utilize this contrast to optically imprint reconfigurable photonic elements comprising diffraction gratings as well as on- and off-axis zone plates. The structures allow for highly repetitive (>10{sup 4}) cycling through the phase transition without structural damage.

  5. Effect of antimony addition on the optical behaviour of germanium selenide thin films

    NASA Astrophysics Data System (ADS)

    Sharma, Parikshit; Rangra, V. S.; Sharma, Pankaj; Katyal, S. C.

    2008-11-01

    This paper reports the influence of antimony (Sb) addition on the optical properties (optical energy gap and refractive index) of thin solid films of the chalcogenide glassy Ge0.17Se0.83-xSbx(x = 0, 0.03, 0.09, 0.12, 0.15) system. This has been done by analysing the transmittance (T) and reflectance (R) spectra in the spectral region 400-2000 nm. It was found that the optical energy gap decreases with increasing Sb content from 1.92 to 1.63 eV with an uncertainty of ± 0.01 eV. The results were interpreted in terms of bond energies and on the basis of the concept of electronegativity. The refractive index has been found to increase with increasing Sb content. The increase in the refractive index has been explained on the basis of polarizability. Dispersion of refractive index has been analysed using the Wemple-DiDomenico single oscillator model. The static refractive index increased from 2.45 to 2.91 for the studied compositions. An estimate of the energy gap has also been taken theoretically and it has been found that both the optical energy gap (measured from T and R spectra) and the theoretical energy gap follow similar trends.

  6. Method for studying the phase function in tunable diffraction optical elements

    SciTech Connect

    Paranin, V D; Tukmakov, K N

    2014-04-28

    A method for studying the phase function in tunable diffraction optical elements is proposed, based on measurement of the transmission of interelectrode gaps. The mathematical description of the method, which is approved experimentally, is developed. The instrumental error effects are analysed. (laser applications and other topics in quantum electronics)

  7. Multilevel micro-structuring of glassy carbon for precision glass molding of diffractive optical elements

    NASA Astrophysics Data System (ADS)

    Prater, Karin; Dukwen, Julia; Scharf, Toralf; Herzig, Hans Peter; Plöger, Sven; Hermerschmidt, Andreas

    2015-03-01

    A consumer market for diffractive optical elements in glass can only be created if high efficient elements are available at affordable prices. In diffractive optics the efficiency and optical properties increases with the number of levels used, but in the same way the costs are multiplied by the number if fabrication steps. Replication of multilevel diffractive optical elements in glass would allow cost efficient fabrication but a suitable mold material is needed. Glassy carbon shows a high mechanical strength, thermal stability and non-sticking adhesion properties, which makes it an excellent candidate as mold material for precision compression molding of low and high glass-transition temperature materials. We introduce an 8 level micro structuring process for glassy carbon molds with standard photolithography and a Ti layer as hard mask for reactive ion etching. The molds were applied to thermal imprinting onto low and high transition temperature glass. Optical performance was tested for the molded samples with different designs for laser beamsplitters. The results show a good agreement to the design specification. Our result allow us to show limitations of our fabrication technique and we discussed the suitability of precision glass molding for cost efficient mass production with a high quality.

  8. Apparatus and method using a holographic optical element for converting a spectral distribution to image points

    NASA Technical Reports Server (NTRS)

    McGill, Matthew J. (Inventor); Scott, Vibart S. (Inventor); Marzouk, Marzouk (Inventor)

    2001-01-01

    A holographic optical element transforms a spectral distribution of light to image points. The element comprises areas, each of which acts as a separate lens to image the light incident in its area to an image point. Each area contains the recorded hologram of a point source object. The image points can be made to lie in a line in the same focal plane so as to align with a linear array detector. A version of the element has been developed that has concentric equal areas to match the circular fringe pattern of a Fabry-Perot interferometer. The element has high transmission efficiency, and when coupled with high quantum efficiency solid state detectors, provides an efficient photon-collecting detection system. The element may be used as part of the detection system in a direct detection Doppler lidar system or multiple field of view lidar system.

  9. Control of Gas Tungsten Arc welding pool shape by trace element addition to the weld pool

    DOEpatents

    Heiple, C.R.; Burgardt, P.

    1984-03-13

    An improved process for Gas Tungsten Arc welding maximizes the depth/width ratio of the weld pool by adding a sufficient amount of a surface active element to insure inward fluid flow, resulting in deep, narrow welds. The process is especially useful to eliminate variable weld penetration and shape in GTA welding of steels and stainless steels, particularly by using a sulfur-doped weld wire in a cold wire feed technique.

  10. Photon mass energy transfer coefficients for elements z=1 to 92 and 48 additional substances of dosimetric interest.

    PubMed

    Kato, Hideki

    2014-07-01

    Photon mass energy transfer coefficient is an essential factor when converting photon energy fluence into kinetic energy released per unit mass (kerma). Although mass attenuation coefficient and mass energy absorption coefficients can be looked up in databases, the mass energy transfer coefficient values are still controversial. In this paper, the photon mass energy transfer coefficients for elements Z=1-92 were calculated based on cross-sectional data for each photon interaction type. Mass energy transfer coefficients for 48 compounds and/or mixtures of dosimetric interest were calculated from coefficient data for elements using Bragg's additivity rule. We additionally developed software that can search these coefficient data for any element or substance of dosimetric interest. The database and software created in this paper should prove useful for radiation measurements and/or dose calculations.

  11. Recent progress in see-through three-dimensional displays using holographic optical elements [Invited].

    PubMed

    Jang, Changwon; Lee, Chang-Kun; Jeong, Jinsoo; Li, Gang; Lee, Seungjae; Yeom, Jiwoon; Hong, Keehoon; Lee, Byoungho

    2016-01-20

    The principles and characteristics of see-through 3D displays are presented. We especially focus on the integral-imaging display system using a holographic optical element (IDHOE), which is able to display 3D images and satisfy the see-through property at the same time. The technique has the advantage of the high transparency and capability of displaying autostereoscopic 3D images. We have analyzed optical properties of IDHOE for both recording and displaying stages. Furthermore, various studies of new applications and system improvements for IDHOE are introduced. Thanks to the characteristics of holographic volume grating, it is possible to implement a full-color lens-array holographic optical element and conjugated reconstruction as well as 2D/3D convertible IDHOE. Studies on the improvements of viewing characteristics including a viewing angle, fill factor, and resolution are also presented. Lastly, essential issues and their possible solutions are discussed as future work.

  12. Fiber optic refractometric sensors using a semi-ellipsoidal sensing element.

    PubMed

    Castro Martinez, Amalia Nallely; Komanec, Matej; Nemecek, Tomas; Zvanovec, Stanislav; Khotiaintsev, Sergei

    2016-04-01

    We present theoretical and experimental results for a fiber optic refractometric sensor employing a semi-ellipsoidal sensing element made of polymethyl methacrylate. The double internal reflection of light inside the element provides sensitivity to the refractive index of the external analyte. We demonstrate that the developed sensor, operating at a wavelength of 632 nm, is capable of measurement within a wide range of refractive indices from n=1.00 to n=1.47 with sensitivity over 500 dB/RIU. A comparison of the developed sensor with two more complex refractometric sensors, one based on tapered optical fiber and the other based on suspended-core microstructure optical fiber, is presented.

  13. Determination of rare earth elements and other trace elements (Y, Mn, Co, Cr) in seawater using Tm addition and Mg(OH)₂ co-precipitation.

    PubMed

    Freslon, Nicolas; Bayon, Germain; Birot, Dominique; Bollinger, Claire; Barrat, Jean Alix

    2011-07-15

    This paper reports on a novel procedure for determining trace element abundances (REE and Y, Cr, Mn, Co) in seawater by inductively coupled plasma sector field mass spectrometry (ICP-SFMS). The procedure uses a combination of pre-concentration using co-precipitation onto magnesium hydroxides and addition of thulium spike. The validity of the method was assessed onto 25 ml volumes of certified reference materials (NASS- and CASS-4) and in house seawater standard. Procedural blanks were determined by applying the same procedure to aliquots of seawater previously depleted in trace elements by successive Mg(OH)(2) co-precipitations, yielding estimated contributions to the studied samples better than 1.1% for all elements, with the exception of Cr (<3.3%) and Co (up to 8%). The reproducibility of the method over the six month duration of the study was smaller than 11% RSD for all the studied elements. Results obtained for NASS-5 and CASS-4 agree well with published working values for trace elements.

  14. Characterization and comparison of 128x128 element nuclear optical dynamic display system resistive arrays

    NASA Astrophysics Data System (ADS)

    Hayes, Alexander G.; Caraco, Fino J.; Harrison, David C.; Sorvari, John M.

    2006-05-01

    Dynamic infrared scene projection is a common technology used to provide end to end testing and characterization of infrared sensor systems. Scene projection technology will play an increasing role in infrared system evaluation and development as the cost and risk of flight testing increases and new display technologies begin to emerge. This paper describes a series of tests performed in the Seeker Experimental System (SES) at MIT Lincoln Laboratory (MIT LL). A small collection of 128×128 element Nuclear Optical Dynamic Display System (NODDS) resistive arrays were tested and compared using FIESTA drive electronics developed by ATK Mission Research. The residual spatial nonuniformity of the NODDS arrays were calculated after applying a sparse grid based nonuniformity correction algorithm developed at MIT LL. The nonuniformity correction algorithm is a slightly modified version of the industry standard sparse grid technique and is outlined in this paper. Additional metrics used to compare the arrays include emitter temporal response, raw nonuniformity, transfer function smoothness, dynamic range, and bad display pixel characteristics.

  15. Finite element analysis of low-cost membrane deformable mirrors for high-order adaptive optics

    NASA Astrophysics Data System (ADS)

    Winsor, Robert S.; Sivaramakrishnan, Anand; Makidon, Russell B.

    1999-10-01

    We demonstrate the feasibility of glass membrane deformable mirror (DM) support structures intended for very high order low-stroke adaptive optics systems. We investigated commercially available piezoelectric ceramics. Piezoelectric tubes were determined to offer the largest amount of stroke for a given amount of space on the mirror surface that each actuator controls. We estimated the minimum spacing and the maximum expected stroke of such actuators. We developed a quantitative understanding of the response of a membrane mirror surface by performing a Finite Element Analysis (FEA) study. The results of the FEA analysis were used to develop a design and fabrication process for membrane deformable mirrors of 200 - 500 micron thicknesses. Several different values for glass thickness and actuator spacing were analyzed to determine the best combination of actuator stoke and surface deformation quality. We considered two deformable mirror configurations. The first configuration uses a vacuum membrane attachment system where the actuator tubes' central holes connect to an evacuated plenum, and atmospheric pressure holds the membrane against the actuators. This configuration allows the membrane to be removed from the actuators, facilitating easy replacement of the glass. The other configuration uses precision bearing balls epoxied to the ends of the actuator tubes, with the glass membrane epoxied to the ends of the ball bearings. While this kind of DM is not serviceable, it allows actuator spacings of 4 mm, in addition to large stroke. Fabrication of a prototype of the latter kind of DM was started.

  16. Competition between planar and central chiral control elements in nucleophilic addition to ferrocenyl imine derivatives.

    PubMed

    Joly, Kévin M; Wilson, Claire; Blake, Alexander J; Tucker, James H R; Moody, Christopher J

    2008-11-07

    Planar chirality associated with the ferrocene in ferrocenyl oximes and hydrazones bearing chiral auxiliaries effectively competes with or overrides the normally excellent stereocontrol afforded by the auxiliary in determining the diastereoselectivity of addition to the C=N bond.

  17. Stratified Volume Diffractive Optical Elements as Low-Mass Coherent Lidar Scanners

    NASA Technical Reports Server (NTRS)

    Chambers, Diana M.; Nordin, Gregory P.; Kavaya, Michael J.

    1999-01-01

    Transmissive scanning elements for coherent laser radar systems are typically optical wedges, or prisms, which deflect the lidar beam at a specified angle and are then rotated about the instrument optical axis to produce a scan pattern. The wedge is placed in the lidar optical system subsequent to a beam-expanding telescope, implying that it has the largest diameter of any element in the system. The combination of the wedge diameter and asymmetric profile result in the element having very large mass and, consequently, relatively large power consumption required for scanning. These two parameters, mass and power consumption, are among the instrument requirements which need to be minimized when designing a lidar for a space-borne platform. Reducing the scanner contributions in these areas will have a significant effect on the overall instrument specifications, Replacing the optical wedge with a diffraction grating on the surface of a thin substrate is a straight forward approach with potential to reduce the mass of the scanning element significantly. For example, the optical wedge that will be used for the SPAce Readiness Coherent Lidar Experiment (SPARCLE) is approximately 25 cm in diameter and is made from silicon with a wedge angle designed for 30 degree deflection of a beam operating at approx. 2 micrometer wavelength. The mass of this element could be reduced by a factor of four by instead using a fused silica substrate, 1 cm thick, with a grating fabricated on one of the surfaces. For a grating to deflect a beam with a 2 micrometer wavelength by 30 degrees, a period of approximately 4 micrometers is required. This is small enough that fabrication of appropriate high efficiency blazed or multi-phase level diffractive optical gratings is prohibitively difficult. Moreover, bulk or stratified volume holographic approaches appear impractical due to materials limitations at 2 micrometers and the need to maintain adequate wavefront quality. In order to avoid the

  18. The effect of selected alloying element additions on properties of Mg-based alloy as bioimplants: A literature review

    NASA Astrophysics Data System (ADS)

    Zhang, Li-Nan; Hou, Zeng-Tao; Ye, Xin; Xu, Zhao-Bin; Bai, Xue-Ling; Shang, Peng

    2013-09-01

    This review investigates the current application limitations of Mg and Mg alloys. The key issues hindering the application of biodegradable Mg alloys as implants are their fast degradation rate and biological consideration. We have discussed the effect of some selected alloying element additions on the properties of the Mg-based alloy, especially the nutrient elements in human (Zn, Mn, Ca, Sr). Different grain sizes, phase constituents and distributions consequently influence the mechanical properties of the Mg alloys. Solution strengthening and precipitation strengthening are enhanced by the addition of alloying elements, generally improving the mechanical properties. Besides, the hot working process can also improve the mechanical properties. Combination of different processing steps is suggested to be adopted in the fabrication of Mg-based alloys. Corrosion properties of these Mg-based alloys have been measured in vitro and in vivo. The degradation mechanism is also discussed in terms of corrosion types, rates, byproducts and response of the surrounding tissues. Moreover, the clinical response and requirements of degradable implants are presented, especially for the nutrient elements (Ca, Mn, Zn, Sr). This review provides information related to different Mg alloying elements and presents the promising candidates for an ideal implant.

  19. James Webb Space Telescope Optical Telescope Element Integrated Science Instrument Module (OTIS) Status

    NASA Technical Reports Server (NTRS)

    Feinberg, Lee; Voyton, Mark; Lander, Julie; Keski-Kuha, Ritva; Matthews, Gary

    2016-01-01

    The James Webb Space Telescope Optical Telescope Element (OTE) and Integrated ScienceInstrument Module (ISIM)are integrated together to form the OTIS. Once integrated, the OTIS undergoes primary mirrorcenter of curvatureoptical tests, electrical and operational tests, acoustics and vibration testing at the Goddard SpaceFlight Center beforebeing shipped to the Johnson Space Center for cryogenic optical testing of the OTIS. In preparationfor the cryogenicoptical testing, the JWST project has built a Pathfinder telescope and has completed two OpticalGround SystemEquipment (OGSE) cryogenic optical tests with the Pathfinder. In this paper, we will summarize opticaltest results todate and status the final Pathfinder test and the OTIS integration and environmental test preparations

  20. Anti-Reflective and Waterproof Hard Coating for High Power Laser Optical Elements

    NASA Astrophysics Data System (ADS)

    Murahara, Masataka; Yabe, Takashi; Uchida, Shigeaki; Yoshida, Kunio; Okamoto, Yoshiaki

    2006-05-01

    A hard coating method of single crystalline porous silica film is widely used for high power laser optical elements in the air. However, there is no protective hard coating method for the elements to survive high power laser irradiance while in the water. We, thus, developed a new method for a waterproof coating with photo-oxidation of silicone oil. The silicone oil was spin-coated onto the surface of optical elements, and then irradiated with a xenon excimer lamp in the air. In this treatment, a protective coating for plastic lenses, mirrors, and nonlinear optical crystals, which are highly deliquescent, was developed by taking advantage of the phenomenon in which organic silicone oil is transformed to inorganic amorphous glass by a process of photo-oxidation. This technique has enabled an optical thin coating film to transmit ultraviolet rays of wavelengths under 200 nm and possess the characteristics of homogeneity, high density, resistance to environment, anti-reflectiveness, resistance to water, and Mohs' scale of 5, which is comparable to apatite. This allows us to cool a slab laser head and use as a mirror for underwater laser welding.

  1. Design of optical element combining Fresnel lens with microlens array for uniform light-emitting diode lighting.

    PubMed

    Wang, Guangzhen; Wang, Lili; Li, Fuli; Kong, Depeng

    2012-09-01

    One kind of optical element combining Fresnel lens with microlens array is designed simply for LED lighting based on geometrical optics and nonimaging optics. This design method imposes no restriction on the source intensity pattern. The designed element has compact construction and can produce multiple shapes of illumination distribution. Taking square lighting as an example, tolerance analysis is carried out to determine tolerance limits for applying the element in the assembly process. This element can produce on-axis lighting and off-axis lighting.

  2. Optical tomography reconstruction algorithm with the finite element method: An optimal approach with regularization tools

    SciTech Connect

    Balima, O.; Favennec, Y.; Rousse, D.

    2013-10-15

    Highlights: •New strategies to improve the accuracy of the reconstruction through mesh and finite element parameterization. •Use of gradient filtering through an alternative inner product within the adjoint method. •An integral form of the cost function is used to make the reconstruction compatible with all finite element formulations, continuous and discontinuous. •Gradient-based algorithm with the adjoint method is used for the reconstruction. -- Abstract: Optical tomography is mathematically treated as a non-linear inverse problem where the optical properties of the probed medium are recovered through the minimization of the errors between the experimental measurements and their predictions with a numerical model at the locations of the detectors. According to the ill-posed behavior of the inverse problem, some regularization tools must be performed and the Tikhonov penalization type is the most commonly used in optical tomography applications. This paper introduces an optimized approach for optical tomography reconstruction with the finite element method. An integral form of the cost function is used to take into account the surfaces of the detectors and make the reconstruction compatible with all finite element formulations, continuous and discontinuous. Through a gradient-based algorithm where the adjoint method is used to compute the gradient of the cost function, an alternative inner product is employed for preconditioning the reconstruction algorithm. Moreover, appropriate re-parameterization of the optical properties is performed. These regularization strategies are compared with the classical Tikhonov penalization one. It is shown that both the re-parameterization and the use of the Sobolev cost function gradient are efficient for solving such an ill-posed inverse problem.

  3. Validating a nondestructive optical method for apportioning colored particulate matter into black carbon and additional components

    PubMed Central

    Yan, Beizhan; Kennedy, Daniel; Miller, Rachel L.; Cowin, James P.; Jung, Kyung-hwa; Perzanowski, Matt; Balletta, Marco; Perera, Federica P.; Kinney, Patrick L.; Chillrud, Steven N.

    2011-01-01

    Exposure of black carbon (BC) is associated with a variety of adverse health outcomes. A number of optical methods for estimating BC on Teflon filters have been adopted but most assume all light absorption is due to BC while other sources of colored particulate matter exist. Recently, a four-wavelength-optical reflectance measurement for distinguishing second hand cigarette smoke (SHS) from soot-BC was developed (Brook et al., 2010; Lawless et al., 2004). However, the method has not been validated for soot-BC nor SHS and little work has been done to look at the methodological issues of the optical reflectance measurements for samples that could have SHS, BC, and other colored particles. We refined this method using a lab-modified integrating sphere with absorption measured continuously from 350 nm to 1000 nm. Furthermore, we characterized the absorption spectrum of additional components of particulate matter (PM) on PM2.5 filters including ammonium sulfate, hematite, goethite, and magnetite. Finally, we validate this method for BC by comparison to other standard methods. Use of synthesized data indicates that it is important to optimize the choice of wavelengths to minimize computational errors as additional components (more than 2) are added to the apportionment model of colored components. We found that substantial errors are introduced when using 4 wavelengths suggested by Lawless et al. to quantify four substances, while an optimized choice of wavelengths can reduce model-derived error from over 10% to less than 2%. For environmental samples, the method was sensitive for estimating airborne levels of BC and SHS, but not mass loadings of iron oxides and sulfate. Duplicate samples collected in NYC show high reproducibility (points consistent with a 1:1 line, R2 = 0.95). BC data measured by this method were consistent with those measured by other optical methods, including Aethalometer and Smoke-stain Reflectometer (SSR); although the SSR looses sensitivity at

  4. Validating a nondestructive optical method for apportioning colored particulate matter into black carbon and additional components.

    PubMed

    Yan, Beizhan; Kennedy, Daniel; Miller, Rachel L; Cowin, James P; Jung, Kyung-Hwa; Perzanowski, Matt; Balletta, Marco; Perera, Federica P; Kinney, Patrick L; Chillrud, Steven N

    2011-12-01

    Exposure of black carbon (BC) is associated with a variety of adverse health outcomes. A number of optical methods for estimating BC on Teflon filters have been adopted but most assume all light absorption is due to BC while other sources of colored particulate matter exist. Recently, a four-wavelength-optical reflectance measurement for distinguishing second hand cigarette smoke (SHS) from soot-BC was developed (Brook et al., 2010; Lawless et al., 2004). However, the method has not been validated for soot-BC nor SHS and little work has been done to look at the methodological issues of the optical reflectance measurements for samples that could have SHS, BC, and other colored particles. We refined this method using a lab-modified integrating sphere with absorption measured continuously from 350 nm to 1000 nm. Furthermore, we characterized the absorption spectrum of additional components of particulate matter (PM) on PM(2.5) filters including ammonium sulfate, hematite, goethite, and magnetite. Finally, we validate this method for BC by comparison to other standard methods. Use of synthesized data indicates that it is important to optimize the choice of wavelengths to minimize computational errors as additional components (more than 2) are added to the apportionment model of colored components. We found that substantial errors are introduced when using 4 wavelengths suggested by Lawless et al. to quantify four substances, while an optimized choice of wavelengths can reduce model-derived error from over 10% to less than 2%. For environmental samples, the method was sensitive for estimating airborne levels of BC and SHS, but not mass loadings of iron oxides and sulfate. Duplicate samples collected in NYC show high reproducibility (points consistent with a 1:1 line, R(2) = 0.95). BC data measured by this method were consistent with those measured by other optical methods, including Aethalometer and Smoke-stain Reflectometer (SSR); although the SSR looses sensitivity at

  5. Validating a nondestructive optical method for apportioning colored particulate matter into black carbon and additional components

    NASA Astrophysics Data System (ADS)

    Yan, Beizhan; Kennedy, Daniel; Miller, Rachel L.; Cowin, James P.; Jung, Kyung-hwa; Perzanowski, Matt; Balletta, Marco; Perera, Federica P.; Kinney, Patrick L.; Chillrud, Steven N.

    2011-12-01

    Exposure of black carbon (BC) is associated with a variety of adverse health outcomes. A number of optical methods for estimating BC on Teflon filters have been adopted but most assume all light absorption is due to BC while other sources of colored particulate matter exist. Recently, a four-wavelength-optical reflectance measurement for distinguishing second hand cigarette smoke (SHS) from soot-BC was developed (Brook et al., 2010; Lawless et al., 2004). However, the method has not been validated for soot-BC nor SHS and little work has been done to look at the methodological issues of the optical reflectance measurements for samples that could have SHS, BC, and other colored particles. We refined this method using a lab-modified integrating sphere with absorption measured continuously from 350 nm to 1000 nm. Furthermore, we characterized the absorption spectrum of additional components of particulate matter (PM) on PM 2.5 filters including ammonium sulfate, hematite, goethite, and magnetite. Finally, we validate this method for BC by comparison to other standard methods. Use of synthesized data indicates that it is important to optimize the choice of wavelengths to minimize computational errors as additional components (more than 2) are added to the apportionment model of colored components. We found that substantial errors are introduced when using 4 wavelengths suggested by Lawless et al. to quantify four substances, while an optimized choice of wavelengths can reduce model-derived error from over 10% to less than 2%. For environmental samples, the method was sensitive for estimating airborne levels of BC and SHS, but not mass loadings of iron oxides and sulfate. Duplicate samples collected in NYC show high reproducibility (points consistent with a 1:1 line, R2 = 0.95). BC data measured by this method were consistent with those measured by other optical methods, including Aethalometer and Smoke-stain Reflectometer (SSR); although the SSR looses sensitivity at

  6. Holographic display for see-through augmented reality using mirror-lens holographic optical element.

    PubMed

    Li, Gang; Lee, Dukho; Jeong, Youngmo; Cho, Jaebum; Lee, Byoungho

    2016-06-01

    A holographic display system for realizing a three-dimensional optical see-through augmented reality (AR) is proposed. A multi-functional holographic optical element (HOE), which simultaneously performs the optical functions of a mirror and a lens, is adopted in the system. In the proposed method, a mirror that is used to guide the light source into a reflection type spatial light modulator (SLM) and a lens that functions as Fourier transforming optics are recorded on a single holographic recording material by utilizing an angular multiplexing technique of volume hologram. The HOE is transparent and performs the optical functions just for Bragg matched condition. Therefore, the real-world scenes that are usually distorted by a Fourier lens or an SLM in the conventional holographic display can be observed without visual disturbance by using the proposed mirror-lens HOE (MLHOE). Furthermore, to achieve an optimized optical recording condition of the MLHOE, the optical characteristics of the holographic material are measured. The proposed holographic AR display system is verified experimentally.

  7. Study of optical design of Blu-ray pickup head system with a liquid crystal element.

    PubMed

    Fang, Yi-Chin; Yen, Chih-Ta; Hsu, Jui-Hsin

    2014-10-10

    This paper proposes a newly developed optical design and an active compensation method for a Blu-ray pickup head system with a liquid crystal (LC) element. Different from traditional pickup lens design, this new optical design delivers performance as good as the conventional one but has more room for tolerance control, which plays a role in antishaking devices, such as portable Blu-ray players. A hole-pattern electrode and LC optics with external voltage input were employed to generate a symmetric nonuniform electrical field in the LC layer that directs LC molecules into the appropriate gradient refractive index distribution, resulting in the convergence or divergence of specific light beams. LC optics deliver fast and, most importantly, active compensation through optical design when errors occur. Simulations and tolerance analysis were conducted using Code V software, including various tolerance analyses, such as defocus, tilt, and decenter, and their related compensations. Two distinct Blu-ray pickup head system designs were examined in this study. In traditional Blu-ray pickup head system designs, the aperture stop is always set on objective lenses. In the study, the aperture stop is on the LC lens as a newly developed lens. The results revealed that an optical design with aperture stop set on the LC lens as an active compensation device successfully eliminated up to 57% of coma aberration compared with traditional optical designs so that this pickup head lens design will have more space for tolerance control.

  8. Circuit elements at optical frequencies from first principles: A synthesis of electronic structure and circuit theories

    NASA Astrophysics Data System (ADS)

    Ramprasad, R.; Tang, C.

    2006-08-01

    A first principles electronic structure based method is presented to determine the equivalent circuit representations of nanostructured physical systems at optical frequencies, via a mapping of the effective permittivity calculated for a lattice of physical nano-elements using density functional theory to that calculated for a lattice of impedances using circuit theory. Specifically, it is shown that silicon nanowires and carbon nanotubes can be represented as series combinations of inductance, capacitance and resistance. It is anticipated that the generality of this approach will allow for an alternate description of physical systems at optical frequencies, and in the realization of novel opto- and nanoelectronic devices, including negative refractive index materials.

  9. Optical laboratory solution and error model simulation of a linear time-varying finite element equation

    NASA Technical Reports Server (NTRS)

    Taylor, B. K.; Casasent, D. P.

    1989-01-01

    The use of simplified error models to accurately simulate and evaluate the performance of an optical linear-algebra processor is described. The optical architecture used to perform banded matrix-vector products is reviewed, along with a linear dynamic finite-element case study. The laboratory hardware and ac-modulation technique used are presented. The individual processor error-source models and their simulator implementation are detailed. Several significant simplifications are introduced to ease the computational requirements and complexity of the simulations. The error models are verified with a laboratory implementation of the processor, and are used to evaluate its potential performance.

  10. Diffractive optical elements fabricated for beam shaping of high-power diode lasers

    NASA Astrophysics Data System (ADS)

    Vogt, Helge; Biertümpfel, Ralf; Pawlowski, Edgar

    2008-02-01

    This paper discusses the use of diffractive optical elements (DOEs) and micro-optics fabricated by precise pressing in glass for beam shaping of high-power diode lasers. The DOEs are used to diffract the light into the point of interest and to improve the laser beam quality. We have realized circular, flat-top and multi-beam intensity profiles. The highest measured diffraction efficiency was higher than 95 %. The new established fabrication process has potential for mass production of DOEs. SCHOTT's precision glass molding process guarantees a very constant quality over the complete production chain.

  11. Rare-Earth Elements in Lighting and Optical Applications and Their Recycling

    NASA Astrophysics Data System (ADS)

    Song, Xin; Chang, Moon-Hwan; Pecht, Michael

    2013-10-01

    Rare-earth elements (REEs) are used in lighting and optical applications to enable color and light adjustment, miniaturization, and energy efficiency. Common applications of REEs include phosphors for light-emitting diodes, lasers, and electronic video displays. This article reviews how REEs are widely used in these applications. However, supply constraints, including rising prices, environmental concerns over mining and refining processes, and China's control over the supply of the vast majority of REEs, are of concern for manufacturers. In view of these supply constraints, this article discusses ways for manufacturers of lighting and optical devices to identify potential substitutes and recycling methods for REEs.

  12. Polarization-induced noise in a fiber-optic Michelson interferometer with Faraday rotator mirror elements

    NASA Astrophysics Data System (ADS)

    Ferreira, L. A.; Santos, J. L.; Farahi, F.

    1995-10-01

    Faraday rotator mirror elements have been used in a number of applications as compensators for induced birefringence in retracing paths. In interferometric systems, such as the fiber-optic Michelson interferometer, this approach proved to be useful in providing maximum fringe visibility and insensitivity to the polarization state of light injected into the interferometer. However, it is found that, when the characteristics of the fiber coupler depend on the polarization state of the input beam, the efficiency of the Faraday mirror elements is limited. Theoretical analysis and experimental results in support of this statement are presented.

  13. The finite element analysis of zoom optical system with no moving parts

    NASA Astrophysics Data System (ADS)

    Shi, PuRui; Li, Lin; Huang, Yifan; Han, Xing; Ma, Bin

    2015-10-01

    For the method that active optical system achieves zoom by changing the surface of deformable mirror, the design of the brake, the rationality of the layout and the actual change of the surface are very critical issues. This paper presents a practical research idea and method. The finite element model of a deformable mirror was established based on finite element analysis software, and the analysis is achieved after configuring the brake method that needed. The feasibility of the drive scheme is verified through comparing the simulation results and the ideal surface. On this basis, the preliminary design of the core components of piezoelectric ceramic driving circuit brake is achieved.

  14. Polarization-induced noise in a fiber-optic Michelson interferometer with Faraday rotator mirror elements.

    PubMed

    Ferreira, L A; Santos, J L; Farahi, F

    1995-10-01

    Faraday rotator mirror elements have been used in a number of applications as compensators for induced birefringence in retracing paths. In interferometric systems, such as the fiber-optic Michelson interferometer, this approach proved to be useful in providing maximum fringe visibility and insensitivity to the polarization state of light injected into the interferometer. However, it is found that, when the characteristics of the fiber coupler depend on the polarization state of the input beam, the efficiency of the Faraday mirror elements is limited. Theoretical analysis and experimental results in support of this statement are presented.

  15. Optical properties and photocatalytic activities of tungsten oxide (WO3) with platinum co-catalyst addition

    NASA Astrophysics Data System (ADS)

    Widiyandari, Hendri; Firdaus, Iqbal; Kadarisman, Vincencius Gunawan Slamet; Purwanto, Agus

    2016-02-01

    This research reported the optical properties and photocatalytic activities of tungsten oxide with platinum co-catalyst addition (WO3/Pt) film. The platinum was deposited on the surface of WO3 particle using photo deposition method, while the film formation of WO3/Pt on the glass substrate was prepared using spray deposition method. The addition of Pt of 0, 1, 2, and 4 wt.% resulted that the energy band gap value of the films were shifted to 2.840, 2.752, 2.623 and 2.507 eV, respectively. The as-prepared films were tested for methylene blue (MB) dye photo-degradation using the LED (light emitting diode) lamp as a visible domestic source light. The enhancement of photocatalytic activity was observed after the addition of Pt as a co-catalyst. The degradation kinetics analysis of the photo-catalyst showed that the Pt addition resulted increasing of photo-catalysis reaction rate constant, k.

  16. An optical region elemental abundance analysis of the chemically peculiar HgMn star chi Lupi

    NASA Technical Reports Server (NTRS)

    Wahlgren, Glenn M.; Adelman, Saul J.; Robinson, Richard D.

    1994-01-01

    The optical spectrum of the chemically peculiar HgMn type binary star chi Lupi has been analyzed to determine atmospheric parameters and elemental abundances. Echelle spectra were obtained with the 3.9 m Anglo-Australian telescope to exploit the extreme shape-lined nature of the spectrum. This study was undertaken in support of ultraviolet analyses currently underway that utilize echell spectra obtained with the Hubble Space Telescope. For the B9.5 V primary star we obtain T(sub eff) = 10650 K, log g = 3.9, and xi = 0 km/s, while for the A2 V secondary, T(sub eff) = 9200 K, log g = 4.0, and xi = 2 km/s. Most of the elemental abundances are typical of HgMn stars with similar T(sub eff) showing an overall iron-peak elemental abundance distribution that is basically solar in nature with enhancement of the light elements Si, P, and S, as well as all detected elements heavier than the iron group. Abundances for several elements have been determined for the first time in this star, including several of the rare-earths. The secondary star spectrum shows Am star characteristics. We also discuss the relative merits of the equivalent width and synthetic spectrum techniques in determining the elemental abundences, concluding that the synthetic spectrum technique is necessary for obtaining abundances with the utmost accuracy.

  17. Approach to improve beam quality of inter-satellite optical communication system based on diffractive optical elements.

    PubMed

    Tan, Liying; Yu, Jianjie; Ma, Jing; Yang, Yuqiang; Li, Mi; Jiang, Yijun; Liu, Jianfeng; Han, Qiqi

    2009-04-13

    For inter-satellite optical communication transmitter with reflective telescope of two-mirrors on axis, a large mount of the transmitted energy will be blocked by central obscuration of the secondary mirror. In this paper, a novel scheme based on diffractive optical element (DOE) is introduced to avoid it. This scheme includes one diffractive beam shaper and another diffractive phase corrector, which can diffract the obscured part of transmitted beam into the domain unobscured by the secondary mirror. The proposed approach is firstly researched with a fixed obscuration ratio of 1/4. Numerical simulation shows that the emission efficiency of new figuration is 99.99%; the beam divergence from the novel inter-satellite optical communication transmitter is unchanged; and the peak intensity of receiver plane is increased about 31% compared with the typical configuration. Then the intensy patterns of receiver plane are analyzed with various obscuration ratio, the corresponding numerical modelling reveals that the intensity patterns with various obscuration ratio are nearly identical, but the amplify of relative peak intensity is getting down with the growth of obscuration ratio. This work can improve the beam quality of inter-satellite optical communication system without affecting any other functionality.

  18. Design and fabrication for the diffractive optical element of an infrared system

    NASA Astrophysics Data System (ADS)

    Yang, Changcheng; Li, Shenghui; Li, Yong; Wang, Bin

    2009-05-01

    A diffractive/refractive system with a relative aperture of f/4.0, the EFL of 150mm at 3.7-4.8μm is designed. A diffractive optical element (DOE) is fabricated by means of diamond turning on a conic substrate of the Germanium lens in this system. The characteristics of the diffractive optical element are analyzed in the software of Diffsys. And the zone radius of DOE and step height are detected by profilometry and result is produced. Test results of DOE are coincided with the design figures and the DOE has tiny surface error and high diffractive efficiency. Result of Modulation Transfer Function (MTF) for the system is tested by Ealing and the tested value is closely approximate to diffractive limit. The DOE has better behaviour of chromatic aberration and athermalization.

  19. Circuit elements at optical frequencies: A synthesis of first principles electronic structure and circuit theories

    NASA Astrophysics Data System (ADS)

    Tang, C.; Ramprasad, R.

    2006-03-01

    We present a new first principles based method to determine the equivalent circuit representations of nanostructured physical systems at optical frequencies. This method involves the determination of the frequency dependent effective permittivity of two constructs: an ordered composite system consisting of physical nano-elements using density functional theory, and an ordered arrangement of impedances using transmission line theory. Matching the calculated effective permittivity functions of these two constructs has enabled a mapping of the physical nano-system to its equivalent circuit. Specifically, we will show that silicon nanowires and carbon nanotubes can be represented as a series combination of inductance, capacitance and resistance. Once this mapping has been reasonably accomplished for a variety of physical systems, the nano-elements can be combined suitably to result in equivalent circuit topologies appropriate for optical and nanoelectronic devices, including left-handed (or negative refractive index) materials.

  20. Radiation induced darkening of the optical elements in the Startracker camera

    SciTech Connect

    White, R.H.; Wirtenson, G.R.

    1993-03-01

    Optical glass flats that closely simulate the elements used in the Startracker lens designs were exposed to doses of ionizing radiation ranging from 0.44 to 1300 krad. Photometer traces determined the transmittance of the samples as a function of both wavelength and dose for wavelengths in the range 300 to 1200 nm. Cerium stabilized glasses used in the radiation stabilized Startracker system showed only a small amount of darkening for doses up to and exceeding 1 Mrad. Glasses used in the unstabilized Startracker design showed significant darkening to visible and ultra-violet spectra for doses as low as 5 krad. Plots of transmittance versus wavelength for various doses are given for each of the Startracker optical elements. Radiation induced absorption parameters that determine the radiation induced absorption coefficient are tabulated and plotted versus wavelength.

  1. 3D holographic head mounted display using holographic optical elements with astigmatism aberration compensation.

    PubMed

    Yeom, Han-Ju; Kim, Hee-Jae; Kim, Seong-Bok; Zhang, HuiJun; Li, BoNi; Ji, Yeong-Min; Kim, Sang-Hoo; Park, Jae-Hyeung

    2015-12-14

    We propose a bar-type three-dimensional holographic head mounted display using two holographic optical elements. Conventional stereoscopic head mounted displays may suffer from eye fatigue because the images presented to each eye are two-dimensional ones, which causes mismatch between the accommodation and vergence responses of the eye. The proposed holographic head mounted display delivers three-dimensional holographic images to each eye, removing the eye fatigue problem. In this paper, we discuss the configuration of the bar-type waveguide head mounted displays and analyze the aberration caused by the non-symmetric diffraction angle of the holographic optical elements which are used as input and output couplers. Pre-distortion of the hologram is also proposed in the paper to compensate the aberration. The experimental results show that proposed head mounted display can present three-dimensional see-through holographic images to each eye with correct focus cues.

  2. Optical Testing and Verification Methods for the James Webb Space Telescope Integrated Science Instrument Module Element

    NASA Technical Reports Server (NTRS)

    Antonille, Scott R.; Miskey, Cherie L.; Ohl, Raymond G.; Rohrbach, Scott O.; Aronstein, David L.; Bartoszyk, Andrew E.; Bowers, Charles W.; Cofie, Emmanuel; Collins, Nicholas R.; Comber, Brian J.; Eichhorn, William L.; Glasse, Alistair C.; Gracey, Renee; Hartig, George F.; Howard, Joseph M.; Kelly, Douglas M.; Kimble, Randy A.; Kirk, Jeffrey R.; Kubalak, David A.; Landsman, Wayne B.; Lindler, Don J.; Malumuth, Eliot M.; Maszkiewicz, Michael; Rieke, Marcia J.; Rowlands, Neil; Sabatke, Derek S.; Smith, Corbett T.; Smith, J. Scott; Sullivan, Joseph F.; Telfer, Randal C.; Plate, Maurice Te; Vila, M. Begona; Warner, Gerry D.; Wright, Raymond H.; Wright, David; Zhou, Julia; Zielinski, Thomas P.

    2016-01-01

    NASA's James Webb Space Telescope (JWST) is a 6.6m diameter, segmented, deployable telescope for cryogenic IR space astronomy (40K). The JWST Observatory includes the Optical Telescope Element (OTE) and the Integrated Science Instrument Module (ISIM) that contains four science instruments (SI) and the fine guider. The SIs are mounted to a composite metering structure. The SI and guider units were integrated to the ISIM structure and optically tested at the NASA Goddard Space Flight Center as a suite using the Optical Telescope Element SIMulator (OSIM). OSIM is a full field, cryogenic JWST telescope simulator. SI performance, including alignment and wave front error, were evaluated using OSIM. We describe test and analysis methods for optical performance verification of the ISIM Element, with an emphasis on the processes used to plan and execute the test. The complexity of ISIM and OSIM drove us to develop a software tool for test planning that allows for configuration control of observations, associated scripts, and management of hardware and software limits and constraints, as well as tools for rapid data evaluation, and flexible re-planning in response to the unexpected. As examples of our test and analysis approach, we discuss how factors such as the ground test thermal environment are compensated in alignment. We describe how these innovative methods for test planning and execution and post-test analysis were instrumental in the verification program for the ISIM element, with enough information to allow the reader to consider these innovations and lessons learned in this successful effort in their future testing for other programs.

  3. Optical testing and verification methods for the James Webb Space Telescope Integrated Science Instrument Module element

    NASA Astrophysics Data System (ADS)

    Antonille, Scott R.; Miskey, Cherie L.; Ohl, Raymond G.; Rohrbach, Scott O.; Aronstein, David L.; Bartoszyk, Andrew E.; Bowers, Charles W.; Cofie, Emmanuel; Collins, Nicholas R.; Comber, Brian J.; Eichhorn, William L.; Glasse, Alistair C.; Gracey, Renee; Hartig, George F.; Howard, Joseph M.; Kelly, Douglas M.; Kimble, Randy A.; Kirk, Jeffrey R.; Kubalak, David A.; Landsman, Wayne B.; Lindler, Don J.; Malumuth, Eliot M.; Maszkiewicz, Michael; Rieke, Marcia J.; Rowlands, Neil; Sabatke, Derek S.; Smith, Corbett T.; Smith, J. Scott; Sullivan, Joseph F.; Telfer, Randal C.; Te Plate, Maurice; Vila, M. Begoña.; Warner, Gerry D.; Wright, David; Wright, Raymond H.; Zhou, Julia; Zielinski, Thomas P.

    2016-09-01

    NASA's James Webb Space Telescope (JWST) is a 6.5m diameter, segmented, deployable telescope for cryogenic IR space astronomy. The JWST Observatory includes the Optical Telescope Element (OTE) and the Integrated Science Instrument Module (ISIM), that contains four science instruments (SI) and the Fine Guidance Sensor (FGS). The SIs are mounted to a composite metering structure. The SIs and FGS were integrated to the ISIM structure and optically tested at NASA's Goddard Space Flight Center using the Optical Telescope Element SIMulator (OSIM). OSIM is a full-field, cryogenic JWST telescope simulator. SI performance, including alignment and wavefront error, was evaluated using OSIM. We describe test and analysis methods for optical performance verification of the ISIM Element, with an emphasis on the processes used to plan and execute the test. The complexity of ISIM and OSIM drove us to develop a software tool for test planning that allows for configuration control of observations, implementation of associated scripts, and management of hardware and software limits and constraints, as well as tools for rapid data evaluation, and flexible re-planning in response to the unexpected. As examples of our test and analysis approach, we discuss how factors such as the ground test thermal environment are compensated in alignment. We describe how these innovative methods for test planning and execution and post-test analysis were instrumental in the verification program for the ISIM element, with enough information to allow the reader to consider these innovations and lessons learned in this successful effort in their future testing for other programs.

  4. Photopolymer-Based Volume Holographic Optical Elements: Design and Possible Applications

    NASA Astrophysics Data System (ADS)

    Bianco, G.; Ferrara, M. A.; Borbone, F.; Roviello, A.; Striano, V.; Coppola, G.

    2015-12-01

    In this paper, Volume Holographic Optical Elements (V-HOEs), such as holographic gratings and spherical lenses, are designed and fabricated by using a prototype of photopolymer. The recording process of V-HOEs and their appropriate characterization are described. Moreover, V-HOEs possible applications as solar concentrator are investigated and results are discussed. Finally, a system that allows passive solar tracking is proposed and preliminary results are reported.

  5. James Webb Space Telescope (JWST) Optical Telescope Element (OTE) Development Status

    NASA Technical Reports Server (NTRS)

    Feinberg, Lee D.

    2004-01-01

    The James Webb Space Telescope (JWST) Optical Telescope Element (OTE) is a segmented, cryogenic telescope scheduled for launch in 2011. In September of 2002, NASA selected prime contractor Northrop Grumman Space Technology (NGST) to build the observatory including management of the OTE. NGST is teamed with subcontractors Ball Aerospace, Alliant Techsystems (ATK). and Kodak. The team has completed several significant design, technology, architecture definition, and manufacturing milestones in the past year that are summarized in this paper.

  6. Annular force based variable curvature mirror aiming to realize non-moving element optical zooming

    NASA Astrophysics Data System (ADS)

    Zhao, Hui; Xie, Xiaopeng; Wei, Jingxuan; Ren, Guorui; Pang, Zhihai; Xu, Liang

    2015-10-01

    Recently, a new kind of optical zooming technique in which no moving elements are involved has been paid much attention. The elimination of moving elements makes optical zooming suitable for applications which has exacting requirements in space, power cost and system stability. The mobile phone and the space-borne camera are two typical examples. The key to realize non-moving elements optical zooming lies in the introduction of variable curvature mirror (VCM) whose radius of curvature could be changed dynamically. When VCM is about to be used to implement optical zoom imaging, two characteristics should be ensured. First, VCM has to provide large enough saggitus variation in order to obtain a big magnification ratio. Second, after the radius of curvature has been changed, the corresponding surface figure accuracy should still be maintained superior to a threshold level to make the high quality imaging possible. In this manuscript, based on the elasticity theory, the physical model of the annular force based variable curvature mirror is established and numerically analyzed. The results demonstrate that when the annular force is applied at the half-the-aperture position, the actuation force is reduced and a smaller actuation force is required to generate the saggitus variation and thus the maintenance of surface figure accuracy becomes easier during the variation of radius of curvature. Besides that, a prototype VCM, whose diameter and thickness are 100mm and 3mm respectively, have been fabricated and the maximum saggitus variation that could be obtained approaches more than 30 wavelengths. At the same time, the degradation of surface figure accuracy is weakly correlated to the curvature radius variation. Keywords: optical zooming; variable curvature mirror; surface figure accuracy; saggitus;

  7. Multi-scale analysis of optic chiasmal compression by finite element modelling.

    PubMed

    Wang, Xiaofei; Neely, Andrew J; McIlwaine, Gawn G; Lueck, Christian J

    2014-07-18

    The precise mechanism of bitemporal hemianopia (a type of partial visual field defect) is still not clear. Previous work has investigated this problem by studying the biomechanics of chiasmal compression caused by a pituitary tumour growing up from below the optic chiasm. A multi-scale analysis was performed using finite element models to examine both the macro-scale behaviour of the chiasm and the micro-scale interactions of the nerve fibres within it using representative volume elements. Possible effects of large deflection and non-linear material properties were incorporated. Strain distributions in the optic chiasm and optic nerve fibres were obtained from these models. The results of the chiasmal model agreed well with the limited experimental results available, indicating that the finite element modelling can be a useful tool for analysing chiasmal compression. Simulation results showed that the strain distribution in nasal (crossed) nerve fibres was much more nonuniform and locally higher than in temporal (uncrossed) nerve fibres. This strain difference between nasal and temporal nerve fibres may account for the phenomenon of bitemporal hemianopia.

  8. Coated photodiode technique for the determination of the optical constants of reactive elements: La and Tb

    NASA Astrophysics Data System (ADS)

    Seely, John F.; Uspenskii, Yurii A.; Kjornrattanawanich, Benjawan; Windt, David L.

    2006-08-01

    A novel technique, utilizing thin films with protective capping layers deposited onto silicon photodiode substrates, has been developed to accurately determine the optical constants of reactive elements such as the rare earths and transition metals. Depositing protected layers on photodiode substrates has three primary advantages over the study of the transmittance of free-standing films and the angle-dependent reflectance of coatings on mirror substrates. First, it is easy to deposit a thin protective capping layer that prevents oxidation or contamination of the underlying reactive layer. Second, very thin layers of materials that have intrinsically low transmittance can be studied. Third, the optical constants are determined from the bulk properties of the protected layer and are not influenced by reflectance from the top surface that can be affected by oxidation or contamination. These and other benefits of this technique will be discussed, and results for La and Tb will be presented. The determined optical constants are significantly different from the CXRO and other tabulated values. The rare earth (lanthanide) elements with atomic numbers 57-71 have 5d or 4f open shells, and this open shell structure results in transmission windows in the extreme ultraviolet wavelength range >45 nm where materials typically have low transmittance. These transmission windows make possible the fabrication of a new class of multilayer interference coatings, based on rare earth elements, with relatively high peak reflectances and narrow reflectance profiles, both important factors for the imaging of solar and laboratory radiation sources with multilayer telescopes.

  9. Finite element modeling of microstructured optical fibers: leaky modes, twisted geometries, and spatial Kerr solitons

    NASA Astrophysics Data System (ADS)

    Nicolet, André; Zolla, Frédéric; Renversez, Gilles; Ould Agha, Yacoub; Drouart, Fabien

    2008-11-01

    Microstructured optical fibers have much more degrees of freedom concerning the geometries and index contrasts than step-index fibers. This richness opens totally new fields of application for fiber optics. The finite element method appears as an extremely versatile tool to compute the propagation modes in such systems as it allows to take into account arbitrary geometries of the cross section and also anisotropic and inhomogeneous (i.e. not only piecewise constant) dielectric permittivities. In this paper, we review some more advanced features: how to compute leaky modes (crucial for the understanding of such kind of fibers) by using perfectly matched layers, how to use helicoidal coordinate systems to determine the influence of a twist on the modes via a two-dimensional model (using equivalent materials), and how to compute spatial solitons in fibers involving Kerr optical medium by taking into account the refractive index inhomogeneities caused by the nonlinearity.

  10. Three dimensional fabrication of optical waveguiding elements for on-chip integration

    NASA Astrophysics Data System (ADS)

    Parsi Sreenivas, V. V.; Bülters, M.; Schröder, M.; Bergmann, R. B.

    2014-05-01

    We present micro polymer optical waveguide elements fabricated using femtosecond laser and two-photon absorption (TPA) process. The POWs are constructed by tightly focusing a laser beam in SU-8 based resists transparent to the laser wavelength for single-photon absorption. The TPA process enables the patterning of the resist in three dimensions at a resolution of 100-200 nm, which provides a high degree of freedom for POW designs. Using this technology, we provide a novel approach to fabricate Three dimensional Polymer Optical Waveguides (3D-POW) and coupling with single mode fibers in the visible wavelength regions. Our research is also focused on fabricating passive micro optical elements such as splitters, combiners and simple logical gates. For this reason we are aiming to achieve optimum coupling efficiency between the 3D-POW and fibers. The technology also facilitates 3D-POW fabrication independent of the substrate material. We present these fabrication techniques and designs, along with supporting numerical simulations and its transmission properties. With a length of 270 μm and polymer core diameter of 9 μm with air cladding, the waveguides possess a total loss of 12 dB. This value also includes the external in and out mode coupling and in continuously being improved upon by design optimization and simulations. We verify the overall feasibility of the design and coupling mechanisms that can be exploited to execute waveguide based optical functions such as filtering and logical operations.

  11. Computer-aided manufacturing for freeform optical elements by ultraprecision micromilling

    NASA Astrophysics Data System (ADS)

    Stoebenau, Sebastian; Kleindienst, Roman; Hofmann, Meike; Sinzinger, Stefan

    2011-09-01

    The successful fabrication of several freeform optical elements by ultraprecision micromilling is presented in this article. We discuss in detail the generation of the tool paths using different variations of a computer-aided manufacturing (CAM) process. Following a classical CAM approach, a reflective beam shaper was fabricated. The approach is based on a solid model calculated by optical design software. As no analytical description of the surface is needed, this procedure is the most general solution for the programming of the tool paths. A second approach is based on the same design data. But instead of a solid model, a higher order polynomial was fitted to the data using computational methods. Taking advantage of the direct programming capabilities of state-of-the-art computerized numerical control units, the mathematics to calculate the polynomial based tool paths on-the-fly during the machining process are implemented in a highly flexible CNC code. As another example for this programming method, the fabrication of a biconic lens from a closed analytical description directly derived from the optical design is shown. We provide details about the different programming methods and the fabrication processes as well as the results of characterizations concerning surface quality and shape accuracy of the freeform optical elements.

  12. The investigation of transient thermal effects in optical elements under high laser intensities

    NASA Astrophysics Data System (ADS)

    Kaskow, Mateusz; Tarka, Jan; Kwiatkowski, Jacek; Zendzian, Waldemar; Gorajek, Lukasz; Jabczynski, Jan K.

    2012-06-01

    The most important limitations in development of high energy and high power lasers based on solid state technology are thermal effects occurring under high intensity and high heat loads. The thermo-optical effects occurring inside output couplers, folding mirrors, output windows can significantly diminish the beam quality of high power lasers and therefore have to be investigated. The knowledge on transient thermal effects occurring inside bulk laser elements exposed on laser intensities of several dozens of kW/cm2 is of special interest for some specific applications (e.g. heat capacity lasers). The aims of work were theoretical analysis of those effects occurring inside the laser mirrors and its experimental verification. The hints for choice of the best materials (from the point of view of thermal limitations) for laser windows and output couplers were pointed out. The special laboratory setup enabling simultaneous registration of thermo-optical effects applying shearing interferometry and wavefront sensing by means of Shack-Hartmann test was worked out. The transient as well as averaged in time thermal-optical effects occurring inside the volume of examined element as a result of surface absorption in the coatings and bulk absorption in the material can be resolved and measured. The resolution of measurements: less than 0.1 K temperature difference and thermally induced optical power of about 0.1 D were demonstrated.

  13. Effect of galactooligosaccharide addition on the physical, optical, and sensory acceptance of vanilla ice cream.

    PubMed

    Balthazar, C F; Silva, H L A; Celeguini, R M S; Santos, R; Pastore, G M; Junior, C A Conte; Freitas, M Q; Nogueira, L C; Silva, M C; Cruz, A G

    2015-07-01

    The effect of the addition of galactooligosaccharide (GOS) on the physicochemical, optical, and sensory characteristics of ice cream was investigated. Vanilla ice cream was supplemented with 0, 1.5, and 3.0% (wt/wt) GOS and characterized for pH, firmness, color, melting, overrun, as well as subjected to a discriminative sensory test (triangle test). For comparison purposes, ice creams containing fructooligosaccharide were also manufactured. The GOS ice creams were characterized by increased firmness and lower melting rates. Different perceptions were reported in the sensory evaluation for the 3.0% GOS ice cream when compared with the control, which was not observed for the fructooligosaccharide ice cream. Overall, the findings suggest it is possible to produce GOS ice cream with improved stability in relation to the physicochemical parameters and sensory perception.

  14. The effect of oxidant addition on ferrous iron removal from multi-element acidic sulphate solutions

    NASA Astrophysics Data System (ADS)

    Mbedzi, Ndishavhelafhi; Ibana, Don; Dyer, Laurence; Browner, Richard

    2017-01-01

    This study was an investigation on the hydrolytic precipitation of iron from simulated pregnant leach solution (PLS) of nickel laterite atmospheric leaching. The effect of equilibrium pH, temperature and the addition of oxidant on total iron (ferrous (Fe (II)) and ferric (Fe (III)), aluminium and chromium removal was investigated together with the associated nickel and cobalt losses to the precipitate. Systematic variations of the experimental variables revealed ≥99% of the ferric iron can be removed from solution at conditions similar to those used in standard partial neutralisation in zinc and nickel production, pH of 2.5 and temperature less than 100 °C with minimal losses (<0.5%) of both nickel and cobalt. Temperature variation from 55 to 90 °C had no significant effect on the magnitude of Fe (III) precipitation but led to a significant increase in aluminium removal from 67% to 95% and improved the filterability of the precipitates. There was no ferrous iron precipitation even at a pH of 3.75 in the absence of an oxidant with its removal (98%) achieved by oxidative precipitation with oxygen gas at pH 3.5. Unlike Fe (III) precipitation, the operating temperature significantly affects oxidative precipitation of Fe (II). Hence, in practical application, the hydrolytic precipitation and oxidation to remove iron must be operated at 85 °C to ensure both ferrous and ferric iron are precipitated.

  15. Focusing and imaging properties of diffractive optical elements with star-ring topological structure

    NASA Astrophysics Data System (ADS)

    Ke, Jie; Zhang, Junyong; Zhang, Yanli; Sun, Meizhi

    2015-08-01

    A kind of diffractive optical elements (DOE) with star-ring topological structure is proposed and their focusing and imaging properties are studied in detail. The so-called star-ring topological structure denotes that a large number of pinholes distributed in many specific zone orbits. In two dimensional plane, this structure can be constructed by two constrains, one is a mapping function, which yields total potential zone orbits, corresponding to the optical path difference (OPD); the other is a switching sequence based on the given encoded seed elements and recursion relation to operate the valid zone orbits. The focusing and imaging properties of DOE with star-ring topological structure are only determined by the aperiodic sequence, and not relevant to the concrete geometry structure. In this way, we can not only complete the traditional symmetrical DOE, such as circular Dammam grating, Fresnel zone plates, photon sieves, and their derivatives, but also construct asymmetrical elements with anisotropic diffraction pattern. Similarly, free-form surface or three dimensional DOE with star-ring topological structure can be constructed by the same method proposed. In consequence of smaller size, lighter weight, more flexible design, these elements may allow for some new applications in micro and nanphotonics.

  16. Extracting More Information from Passive Optical Tracking Observations for Reliable Orbit Element Generation

    NASA Astrophysics Data System (ADS)

    Bennett, J.; Gehly, S.

    2016-09-01

    This paper presents results from a preliminary method for extracting more orbital information from low rate passive optical tracking data. An improvement in the accuracy of the observation data yields more accurate and reliable orbital elements. A comparison between the orbit propagations from the orbital element generated using the new data processing method is compared with the one generated from the raw observation data for several objects. Optical tracking data collected by EOS Space Systems, located on Mount Stromlo, Australia, is fitted to provide a new orbital element. The element accuracy is determined from a comparison between the predicted orbit and subsequent tracking data or reference orbit if available. The new method is shown to result in a better orbit prediction which has important implications in conjunction assessments and the Space Environment Research Centre space object catalogue. The focus is on obtaining reliable orbital solutions from sparse data. This work forms part of the collaborative effort of the Space Environment Management Cooperative Research Centre which is developing new technologies and strategies to preserve the space environment (www.serc.org.au).

  17. Composite axilens-axicon diffractive optical elements for generation of ring patterns with high focal depth

    NASA Astrophysics Data System (ADS)

    Dharmavarapu, Raghu; Vijayakumar, A.; Brunner, R.; Bhattacharya, Shanti

    2016-03-01

    A binary Fresnel Zone Axilens (FZA) is designed for the infinite conjugate mode and the phase profile of a refractive axicon is combined with it to generate a composite Diffractive Optical Element (DOE). The FZA designed for two focal lengths generates a line focus along the propagation direction extending between the two focal planes. The ring pattern generated by the axicon is focused through this distance and the radius of the ring depends on the propagation distance. Hence, the radius of the focused ring pattern can be tuned, during the design process, within the two focal planes. The integration of the two functions was carried out by shifting the location of zones of FZA with respect to the phase profile of the refractive axicon resulting in a binary composite DOE. The FZAs and axicons were designed for different focal depth values and base angles respectively, in order to achieve different ring radii within the focal depth of each element. The elements were simulated using scalar diffraction formula and their focusing characteristics were analyzed. The DOEs were fabricated using electron beam direct writing and evaluated using a fiber coupled diode laser. The tunable ring patterns generated by the DOEs have prospective applications in microdrilling as well as microfabrication of circular diffractive and refractive optical elements.

  18. Magnifications of Single and Dual Element Accommodative Intraocular Lenses: Paraxial Optics Analysis

    PubMed Central

    Ale, Jit B; Manns, Fabrice; Ho, Arthur

    2010-01-01

    Purpose Using an analytical approach of paraxial optics, we evaluated the magnification of a model eye implanted with single-element (1E) and dual-element (2E) translating-optics accommodative intraocular lenses (AIOL) with an objective of understanding key control parameters relevant to their design. Potential clinical implications of the results arising from pseudophakic accommodation were also considered. Methods Lateral and angular magnifications in a pseudophakic model eye were analyzed using the matrix method of paraxial optics. The effects of key control parameters such as direction (forward or backward) and distance (0 to 2 mm) of translation, power combinations of the 2E-AIOL elements (front element power range +20.0 D to +40.0 D), and amplitudes of accommodation (0 to 4 D) were tested. Relative magnification, defined as the ratio of the retinal image size of the accommodated eye to that of unaccommodated phakic (rLM1) or pseudophakic (rLM2) model eyes, was computed to determine how retinal image size changes with pseudophakic accommodation. Results Both lateral and angular magnifications increased with increased power of the front element in 2E-AIOL and amplitude of accommodation. For a 2E-AIOL with front element power of +35 D, rLM1 and rLM2 increased by 17.0% and 16.3%, respectively, per millimetre of forward translation of the element, compared to the magnification at distance focus (unaccommodated). These changes correspond to a change of 9.4% and 6.5% per dioptre of accommodation, respectively. Angular magnification also increased with pseudophakic accommodation. 1E-AIOLs produced consistently less magnification than 2E-AIOLs. Relative retinal image size decreased at a rate of 0.25% with each dioptre of accommodation in the phakic model eye. The position of the image space nodal point shifted away from the retina (towards the cornea) with both phakic and pseudophakic accommodation. Conclusion Power of the mobile element, and amount and direction of

  19. Influence of the spatial frequency on the diffractive optical elements fabrication in PDLCs

    NASA Astrophysics Data System (ADS)

    Fernández, R.; Fenoll, S.; Gallego, S.; Márquez, A.; Francés, J.; Navarro Fuster, V.; Beléndez, A.; Pascual, I.

    2016-09-01

    Photopolymers are classical holographic recording materials. Recently their chemical composition and the fabrication techniques have been optimized for many new applications such as interconnectors, solar concentrations, 2-D photonic structures, or wave-guides. Their potential usefulness has been drastically increased by the introduction of dispersed liquid crystal molecules; these components can be concentrated in the non-exposed zones of the material by a photopolymerization induced phase separation process (PIPS). Therefore, by combining polymer and dispersed liquid crystal (PDLC) has emerged as a new composite material for switchable diffractive optical elements (DOEs). Parallel to the material advances some techniques have been proposed to record very low spatial frequencies DOE's. Different researchers have reported proposes to record DOE like fork gratings, photonics structures, lenses, sinusoidal, blazed or fork gratings. In this work we have studied the behavior of a PDLC material to record DOE's with different spatial periods: from 1 μm, using holographic technique, to more than 200 μm, Liquid Cristal on Silicon (LCoS) display working in mostly amplitude mode as a master. Due to the improvement in the spatial light modulation technology and the pixel miniaturization, this technique permits us store gratings with spatial frequencies until few microns. Additionally, this technology permits us an accurate and dynamic control of the phase and the amplitude of the recording beam. In particular, for our case, to generate the blazed gratings, we use an LCoS-Pluto provided by Holoeye with a resolution of 1920x1080 (HDTV) pixels and a pixel size of 7.7x7.7 m2.

  20. Concentrating partially entangled W-class states on nonlocal atoms using low- Q optical cavity and linear optical elements

    NASA Astrophysics Data System (ADS)

    Cao, Cong; Chen, Xi; Duan, YuWen; Fan, Ling; Zhang, Ru; Wang, TieJun; Wang, Chuan

    2016-10-01

    Entanglement plays an important role in quantum information science, especially in quantum communications. Here we present an efficient entanglement concentration protocol (ECP) for nonlocal atom systems in the partially entangled W-class states, using the single-photon input-output process regarding low- Q cavity and linear optical elements. Compared with previously published ECPs for the concentration of non-maximally entangled atomic states, our protocol is much simpler and more efficient as it employs the Faraday rotation in cavity quantum electrodynamics (QED) and the parameter-splitting method. The Faraday rotation requires the cavity with low- Q factor and weak coupling to the atom, which makes the requirement for entanglement concentration much less stringent than the previous methods, and achievable with current cavity QED techniques. The parameter-splitting method resorts to linear-optical elements only. This ECP has high efficiency and fidelity in realistic experiments, and some imperfections during the experiment can be avoided efficiently with currently available techniques.

  1. Improving the analytical performance of hydride generation non-dispersive atomic fluorescence spectrometry. Combined effect of additives and optical filters

    NASA Astrophysics Data System (ADS)

    D'Ulivo, Alessandro; Bramanti, Emilia; Lampugnani, Leonardo; Zamboni, Roberto

    2001-10-01

    The effects of tetrahydroborate and acid concentration and the presence of L-cysteine and thiourea were investigated in the determination of As, Bi and Sn using continuous flow hydride generation atomic fluorescence spectrometry (HG AFS). The aim was to find conditions allowing the control of those effects exerting negative influence on the analytical performance of the HG AFS apparatus. The effects taken into account were: (i) the radiation scattering generated by carryover of solution from the gas-liquid separator to the atomizer; (ii) the introduction of molecular species generated by tetrahydroborate decomposition into the atomizer; and (iii) interference effects arising from other elements in the sample matrix and from different acids. The effects (i) and (ii) could be controlled using mild reaction conditions in the HG stage. The effect of HG conditions on carryover was studied by radiation scattering experiments without hydride atomization. Compromised HG conditions were found by studying the effects of tetrahydroborate (0.1-20 g l -1) and acid (0.01-7 mol l -1) concentration, and the addition of L-cysteine (10 g l -1) and thiourea (0.1 mol l -1) on the HG AFS signals. The effect of optical filters was investigated with the aim of improving the signal-to-noise ratio. Optical filters with peak wavelengths of 190 and 220 nm provided an improvement of detection limits by factors of approximately 4 and 2 for As and Te, respectively. Under optimized conditions the detection limits were 6, 5, 3, 2, 2 and 9 ng l -1 for As, Sb, Bi, Sn, Se and Te, respectively. Good tolerance to various acid compositions and sample matrices was obtained by using L-cysteine or thiourea as masking agents. Determination of arsenic in sediment and copper certified reference materials, and of bismuth in steel, sediment, soil and ore certified reference material is reported.

  2. Effect of Zn addition on non-resonant third-order optical nonlinearity of the Cu-doped germano-silicate optical glass fiber.

    PubMed

    Ju, Seongmin; Watekar, Pramod R; Jeong, Seongmook; Kim, Youngwoong; Han, Won-Taek

    2012-01-01

    Cu/Zn-codoped germano-silicate optical glass fiber was manufactured by using the modified chemical vapor deposition (MCVD) process and solution doping process. To investigate the reduction effect of Zn addition on Cu metal formation in the core of the Cu/Zn-codoped germano-silicate optical glass fiber, the optical absorption property and the non-resonant third-order optical nonlinearity were measured. Absorption peaks at 435 nm and 469 nm in the Cu/Zn-codoped germano-silicate optical glass fiber were contributed to Cu metal particles and ZnO semiconductor particles, respectively. The effective non-resonant optical nonlinearity, gamma, of the Cu/Zn-codoped germano-silicate optical glass fiber was measured to be 1.5097 W(-1) x km(-1) by using the continuous-wave self-phase modulation method. The gamma of the Cu/Zn-codoped germano-silicate optical glass fiber was about four times larger than that of the reference germano-silicate optical glass fiber without any dopants. The increase of the effective non-resonant optical nonlinearity, gamma, of the Cu/Zn-codoped germano-silicate optical glass fiber, can be attributed to the enhanced nonlinear polarization due to incorporated ZnO semiconductor particles and Cu metal ions in the glass network. The Cu/Zn-codoped germano-silicate optical glass fiber showed high nonlinearity and low transmission loss at the optical communication wavelength, which makes it suitable for high-speed-high-capacity optical communication systems.

  3. Quantification of morphology of bacterial colonies using laser scatter measurements and solid element optical modeling

    NASA Astrophysics Data System (ADS)

    Leavesley, Silas; Bayraktar, Bülent; Venkatapathi, Murugesan; Hirleman, E. Dan; Bhunia, Arun K.; Robinson, J. Paul; Hassler, Richard; Smith, Linda; Rajwa, Bartek

    2007-02-01

    Traditional biological and chemical methods for pathogen identification require complicated sample preparation for reliable results. Optical scattering technology has been used for identification of bacterial cells in suspension, but with only limited success. Our published reports have demonstrated that scattered light based identification of Listeria colonies growing on solid surfaces is feasible with proper pattern recognition tools. Recently we have extended this technique to classification of other bacterial genera including, Salmonella, Bacillus, and Vibrio. Our approach may be highly applicable to early detection and classification of pathogens in food-processing industry and in healthcare. The unique scattering patterns formed by colonies of different species are created through differences in colony microstructure (on the order of wavelength used), bulk optical properties, and the macroscopic morphology. While it is difficult to model the effect on scatter-signal patterns owing to the microstructural changes, the influence of bulk optical properties and overall shape of colonies can be modeled using geometrical optics. Our latest research shows that it is possible to model the scatter pattern of bacterial colonies using solid-element optical modeling software (TracePro), and theoretically assess changes in macro structure and bulk refractive indices. This study allows predicting the theoretical limits of resolution and sensitivity of our detection and classification methods. Moreover, quantification of changes in macro morphology and bulk refractive index provides an opportunity to study the response of colonies to various reagents and antibiotics.

  4. Linking the gyroscope to the imager's optical axis and the laser in finite element optomechanical models

    NASA Astrophysics Data System (ADS)

    Hatheway, Alson E.

    2011-05-01

    Control systems engineers are good at controlling the axis of a gyroscope but that is not quite the same thing as controlling the lines of sight of the optical instruments. That difference often remains a large (and uneasy) uncertainty until the system is actually built and tested. This paper describes how the author couples the optical lines of sight (imaging and non-imaging) to the control system's sensors (gyroscopes and accelerometers) using the optical prescription data and the stiffness, mass and damping matrices of a proposed structure. The mechanical engineer is then able to iterate and optimize the structural design in a finite element modeler/analyzer (Patran/Nastran, for instance) to minimize the errors between the control system's sensors and the optical lines of sight. The engineer then includes the optical lines of sight in the transfer functions and eigenvectors that he passes to the control systems engineer for his design of the control systems. The author illustrates his method with an example from his recent practice.

  5. Differential-interference-contrast digital in-line holography microscopy based on a single-optical-element.

    PubMed

    Zhang, Yuchao; Xie, Changqing

    2015-11-01

    Both digital in-line holography (DIH) and zone plate-based microscopy have received considerable interest as powerful imaging tools. However, the former suffers from a twin-image noise problem. The latter suffers from low efficiency and difficulty in fabrication. Here, we present an effective and efficient phase-contrast imaging approach, named differential-interference-contrast digital in-line holography (DIC-DIH), by using a single optical element to split the incident light into a plane wave and a converging spherical wave and generate a two-dimensional (2D) DIC effect simultaneously. Specifically, to improve image contrast, we present a new single optical element, termed 2D DIC compound photon sieves, by combining two overlaid binary gratings and a compound photon sieve through two logical XOR operations. The proof-of-concept experiments demonstrate that the proposed technique can eliminate the twin-image noise problem and improve image contrast with high efficiency. Additionally, we present an example of the phase-contrast imaging nonuniform thick photoresist development process.

  6. Influence of the set-up on the recording of diffractive optical elements into photopolymers

    NASA Astrophysics Data System (ADS)

    Gallego, S.; Fernández, R.; Márquez, A.; Neipp, C.; Beléndez, A.; Pascual, I.

    2014-05-01

    Photopolymers are often used as a base of holographic memories displays. Recently the capacity of photopolymers to record diffractive optical elements (DOE's) has been demonstrated. To fabricate diffractive optical elements we use a hybrid setup that is composed by three different parts: LCD, optical system and the recording material. The DOE pattern is introduced by a liquid crystal display (LCD) working in the amplitude only mode to work as a master to project optically the DOE onto the recording material. The main advantage of this display is that permit us modify the DOE automatically, we use the electronics of the video projector to send the voltage to the pixels of the LCD. The LCD is used in the amplitude-mostly modulation regime by proper orientation of the external polarizers (P); then the pattern is imaged onto the material with an increased spatial frequency (a demagnifying factor of 2) by the optical system. The use of the LCD allows us to change DOE recorded in the photopolymer without moving any mechanical part of the set-up. A diaphragm is placed in the focal plane of the relay lens so as to eliminate the diffraction orders produced by the pixelation of the LCD. It can be expected that the final pattern imaged onto the recording material will be low filtered due to the finite aperture of the imaging system and especially due to the filtering process produced by the diaphragm. In this work we analyze the effect of the visibility achieved with the LCD and the high frequency cut-off due to the diaphragm in the final DOE recorded into the photopolymer. To simulate the recording we have used the fitted values parameters obtained for PVA/AA based photopolymers and the 3 dimensional models presented in previous works.

  7. Mathematical simulation of the optical system of a fiber-optic measuring micro motion converter with a cylindrical lens modulation element

    NASA Astrophysics Data System (ADS)

    Murashkina, T. I.; Motin, A. V.; Badeeva, E. A.

    2017-01-01

    The paper presents the results of mathematical modeling to determine the physical, structural and technological parameters of differential fiber-optic micro motion converters with a cylindrical lens, which are basic elements of the technical solutions for fiber-optic sensors of various physical quantities used in the industry in automated control systems.

  8. Soft-x-ray magneto-optical Kerr effect and element-specific hysteresis measurement

    SciTech Connect

    Kortright, J.B.; Rice, M.

    1997-04-01

    Interest in the utilization of x-ray magneto-optical properties to provide element-specific magnetic information, combined with recent development of tunable linear polarizers for spectroscopic polarization measurement, have led the authors to the study of magneto-optical rotation (MOR) near core levels of magnetic atoms in magnetic multilayer and alloy films. Their initial observation of Faraday rotation (in transmission) demonstrated that for Fe MOR is easily measured and is larger at its L{sub 3} resonance than in the near-visible spectral regions. This work also demonstrated that the spectroscopic behavior of the MOR signal in transmission, resulting from the differential reaction of left- and right-circular components of a linearly polarized beam, is related to the magnetic circular dichroism (MCD), or differential absorption, as expected by a Kramers-Kronig transformation. Thus MCD measurements using circular polarization and MOR measurements using linear polarization can provide complementary, and in some cases equivalent, information. On beamline 6.3.2 the authors have begun to investigate soft x-ray MOR in the reflection geometry, the x-ray magneto-optic Kerr effect (XMOKE). Early measurements have demonstrated the ability to measure element-specific hysteresis loops and large rotations compared to analogous near-visible measurements. The authors are investigating the spectral dependence of the XMOKE signal, and have initiated systematic materials studies of sputter-deposited films of Fe, Fe{sub x}Cr{sub 1{minus}x} alloys, and Fe/Cr multilayers.

  9. Parametric studies of magnetic-optic imaging using finite-element models

    NASA Astrophysics Data System (ADS)

    Chao, C.; Udpa, L.; Xuan, L.; Fitzpatrick, G.; Thorne, D.; Shih, W.

    2000-05-01

    Magneto-optic imaging is a relatively new sensor application of bubble memory technology to NDI. The Magneto-Optic Imager (MOI) uses a magneto-optic (MO) sensor to produce analog images of magnetic flux leakage from surface and subsurface defects. The flux leakage is produced by eddy current induction techniques in nonferrous metals and magnetic yokes are used in ferromagnetic materials. The technique has gained acceptance in the aircraft maintenance industry for use to detect surface-breaking cracks and corrosion. Until recently, much of the MOI development has been empirical in nature since the electromagnetic processes that produce images are rather complex. The availability of finite element techniques to numerically solve Maxwell's equations, in conjunction with MOI observations, allows greater understanding of the capabilities of the instrument. In this paper, we present a systematic set of finite element calculations along with MOI measurements on specific defects to quantify the current capability of the MOI as well as its desired performance. Parametric studies including effects of liftoff and proximity of edges are also studied.—This material is based upon work supported by the Federal Aviation Administration under Contract #DTFA03-98-D-00008, Delivery Order #IA013 and performed at Iowa State University's Center for NDE as part of the Center for Aviation Systems Reliability program.

  10. Measurement of Black (BC) and Elemental (EC) Carbon by an Optical and a Thermal- optical Method: An Intercomparison

    NASA Astrophysics Data System (ADS)

    Ahmed, T.; Dutkiewicz, V. A.; Khan, A. R.; Husain, L.

    2009-05-01

    Elemental or Black carbon (EC or BC) aerosol emitted into the atmosphere from incomplete combustion of fossil fuel, biomass and forest fires absorbs solar radiations and contributes to global warming. EC or BC is defined based on different analytical methods used for measuring the same fraction of carbonaceous aerosol. The different methods give different results which can vary widely. There is no accepted standard available to accurately quantify EC and therefore measurements between different methods need to be compared to reduce the bias. In this study intercomparison of data between two widely used techniques, BC obtained using optical method (non-destructive technique) and EC obtained using thermal-optical methods (destructive technique) are performed on aerosol samples collected on Whatman 41 filter paper from two rural sites, Whiteface Mountain (WFM) and Mayville, NY. Daily aerosol samples from six months at Mayville collected during 1998 and 2002 and fourteen months from WFM collected during 1996 and 2002 were analyzed using Sunset thermal-optical transmittance (TOT) elemental/organic carbon (EC/OC) analyzer and Magee Scientific Transmissiometer (Model OT-21). Total numbers of samples analyzed from the two sites were around 400. Transmissiometer used for BC measurement is based on optical attenuation of light and its working principle is similar to that of widely used Aethalometer. Whatman 41 filters are not suitable for direct EC measurement using EC/OC analyzer, so a pretreatment technique was developed and EC was subsequently transferred on 47 mm quartz filter paper. The total analysis time for individual sample using Transmissiometer is short (˜ 3-5 min) compared with ˜ 20-25 minutes for EC/OC analyzer excluding the time required for chemical pre-treatment (which can be up to 60 min). Reasonably good correlation, r2>0.8 and BC/EC slope close to 1 was obtained for concentrations up to 600 ngm- 3. For concentration >600 ngm-3 the relationship tends to

  11. Application of prestressed structural elements in the erection of heavy viscoelastic arched structures with the use of an additive technology

    NASA Astrophysics Data System (ADS)

    Manzhirov, A. V.; Parshin, D. A.

    2016-11-01

    The process of erection an object under the action of gravity forces in the absence of additional loads is studied together with the technology of application of prestressed structure elements. The mathematically two-dimensional engineering problem of mechanics of gradual building of a heavy semicircular vault from a prestressed viscoelastic homogeneously aging material is solved analytically. The vault fixation on a rigid horizontal base by sliding fixation, which ensures continuous smooth contact between the vault foot and the base, is considered. The performed computations permit demonstrating high efficiency of preliminary stress creation in the material elements added to the vault in the process of its building in order to control its technological stress state. It is shown that this measure permits significantly decreasing the final values of the separating contact stresses on the foot of the built vault and obtaining the final state of the whole structure which is safer with respect to the level of tensile stresses than that obtain by using unstressed elements.

  12. Effect of Sm{sub 2}O{sub 3} addition on electrical and optical properties of lithium borate glasses

    SciTech Connect

    Gedam, R. S.; Ramteke, D. D.

    2012-06-05

    The electrical and optical property of lithium borate glasses was investigated. It is observed that conductivity decreases while density and refractive index increases with the addition of Sm{sub 2}O{sub 3}. Radiation length of glasses was determined and it is observed that radiation length decreases with the addition of Sm{sub 2}O{sub 3}.

  13. Optical logic inverter and AND elements using laser or light-emitting diodes and photodetectors in a bistable system.

    PubMed

    Okumura, K; Ogawa, Y; Ito, H; Inaba, H

    1984-11-01

    Fundamental optical digital data-processing functions of optical inverter and optical AND elements are proposed and demonstrated experimentally for the first reported time using light-emitting diodes and a photodetector in a hybrid optoelectronic bistable system. The inherent simplicity of these bistable optical devices that use either a laser or a light-emitting diode should make it possible to realize these optical logic functions by monolithic optoelectronic integration. Specific integration schemes are also proposed, and future interesting and useful applications are discussed.

  14. Activation of IFN-beta element by IRF-1 requires a posttranslational event in addition to IRF-1 synthesis.

    PubMed Central

    Watanabe, N; Sakakibara, J; Hovanessian, A G; Taniguchi, T; Fujita, T

    1991-01-01

    Expression of the Type I IFN (i.e., IFN-alpha s and IFN-beta) genes is efficiently induced by viruses at the transcriptional level. This induction is mediated by at least two types of positive regulatory elements located in the human IFN-beta gene promoter: (1) the repeated elements which bind both the transcriptional activator IRF-1 and the repressor IRF-2 (IRF-elements; IRF-Es), and (2) the kappa B element (kappa B-E), which binds NF kappa B and is located between the IRF-Es and the TATA box. In this study we demonstrate that a promoter containing synthetic IRF-E, which displays high affinity for the IRFs can be efficiently activated by Newcastle disease virus (NDV). In contrast, such activation was either very weak or nil when cells were treated by IFN-beta or tumor necrosis factor-alpha (TNF-alpha), despite the fact they both efficiently induce de novo synthesis of the short-lived IRF-1 in L929 cells. In fact, efficient activation of the IRF-E apparently requires an event in addition to de novo IRF-1 induction, which can be elicited by NDV even in the presence of protein synthesis inhibitor, cycloheximide. Moreover, efficient activation of the IRF-E by NDV is specifically inhibited by the protein kinase inhibitor, Staurosporin. Hence our results suggest the importance of IRF-1 synthesis and post-translational modification event(s), possibly phosphorylation for the efficient activation of IRF-Es, which are otherwise under negative regulation by IRF-2. Images PMID:1886766

  15. Diffractive optical element with same diffraction pattern for multicolor light-emitting diodes.

    PubMed

    Chen, Mengzhu; Wang, Qixia; Gu, Huarong; Tan, Qiaofeng

    2016-01-01

    The wavelength-division multiplexing technique can be utilized in visible light communication to increase the channel capacity when a multicolor mixed white LED is used as light source. In such an application, the illumination area of LEDs should be invariant to the incident wavelength, so as to decrease interference within the adjacent regions. Diffractive optical elements (DOEs) can be used in the optical transmitter system to shape the diffraction patterns into polygons. However, traditional DOEs illuminated by a multicolor mixed white LED would result into diffraction patterns with unequal sizes. In this paper, a hybrid algorithm which combines particle swarm optimization with a genetic algorithm is proposed for multicolor oriented DOEs design. A DOE is designed and fabricated for blue and red LEDs, and experimental results show that diffraction patterns with rather good uniformity as well as quasi-equal size for red and blue LEDs are obtained.

  16. Effectiveness of holographic optical element module sensor in measuring blood prothrombin time

    NASA Astrophysics Data System (ADS)

    Lin, Yu-Cheng; Yen, Shih-Chieh; Cheng, Stone; Huang, Tony

    2014-07-01

    A small-form-factor holographic optical element (HOE) module, which was mounted on a dual-stage seesaw actuator, was utilized to evaluate blood coagulation in real time. The method involved assessing the decrease in transmitted light of the blood sample surface when the clotting is formed. The prothrombin time (PT) was measured by illumining and focusing a 635 nm laser beam onto the sample. As the fibrinogen turned into non-solute fibrin, the transmitted efficiency and total intensity of the reflected light from the reflector changed. A low-pass filter suppressed the noise in the coagulation-related transient response to yield accurate signals. Finally, the PT measurements were compared to those made classically using other optical sensors.

  17. Spatial and temporal thermal analysis of acousto-optic deflectors using finite element analysis model.

    PubMed

    Jiang, Runhua; Zhou, Zhenqiao; Lv, Xiaohua; Zeng, Shaoqun; Huang, Zhifeng; Zhou, Huaichun

    2012-07-01

    Thermal effects greatly influence the optical properties of the acousto-optic deflectors (AODs). Thermal analysis plays an important role in modern AOD design. However, the lack of an effective method of analysis limits the prediction in the thermal performance. In this paper, we propose a finite element analysis model to analyze the thermal effects of a TeO(2)-based AOD. Both transducer heating and acoustic absorption are considered as thermal sources. The anisotropy of sound propagation is taken into account for determining the acoustic absorption. Based on this model, a transient thermal analysis is employed using ANSYS software. The spatial temperature distributions in the crystal and the temperature changes over time are acquired. The simulation results are validated by experimental results. The effect of heat source and heat convection on temperature distribution is discussed. This numerical model and analytical method of thermal analysis would be helpful in the thermal design and practical applications of AODs.

  18. Design and verification of diffractive optical elements for speckle generation of 3-D range sensors

    NASA Astrophysics Data System (ADS)

    Du, Pei-Qin; Shih, Hsi-Fu; Chen, Jenq-Shyong; Wang, Yi-Shiang

    2016-12-01

    The optical projection using speckles is one of the structured light methods that have been applied to three-dimensional (3-D) range sensors. This paper investigates the design and fabrication of diffractive optical elements (DOEs) for generating the light field with uniformly distributed speckles. Based on the principles of computer generated holograms, the iterative Fourier transform algorithm was adopted for the DOE design. It was used to calculate the phase map for diffracting the incident laser beam into a goal pattern with distributed speckles. Four patterns were designed in the study. Their phase maps were first examined by a spatial light modulator and then fabricated on glass substrates by microfabrication processes. Finally, the diffraction characteristics of the fabricated devices were verified. The experimental results show that the proposed methods are applicable to the DOE design of 3-D range sensors. Furthermore, any expected diffraction area and speckle density could be possibly achieved according to the relations presented in the paper.

  19. Optical isolator based on the electro-optic effect in periodically poled lithium niobate with the addition of a half domain.

    PubMed

    Shi, Lei; Tian, Linghao; Chen, Xianfeng

    2012-12-20

    We propose an optical isolator based on the electro-optic (EO) effect of periodically poled lithium niobate (PPLN). When the EO effect occurs in PPLN under a TE field, each domain serves as a half-wave plate under the quasi-phase-matching condition, and PPLN shows optical activity similar to quartz. The introduction of an additional half-domain to the normal PPLN changes the incident azimuth angle of the reflected light. As a result, the reflected light does not return to the original polarization state. Thus, the optical rotation accumulates and optical isolation occurs. The isolator can be employed for all linearly polarized light and has the advantage of being used in a weak-light system with low driving voltage and high isolation contrast.

  20. Generation of Bessel Beams at mm- and Sub mm-wavelengths by Binary Optical Elements

    NASA Astrophysics Data System (ADS)

    Yu, Y. Z.; Dou, W. B.

    2008-07-01

    In this paper, binary optical elements (BOE’s) are designed for generating Bessel beams at mm- and sub mm- wavelengths. The design tool is to combine a genetic algorithm (GA) for global optimization with a two-dimension finite-difference time-domain (2-D FDTD) method for rigorous electromagnetic computation. The design process for converting a normally incident Gaussian beam into a Bessel beam is described in detail. Numerical results demonstrate that the designed BOE’s can not only successfully produce arbitrary order Bessel beams, but also have higher diffraction efficiencies when compared with amplitude holograms.

  1. Design of a miniature SWIR hyperspectral snapshot imager utilizing multivariate optical elements

    NASA Astrophysics Data System (ADS)

    Priore, Ryan; Dougherty, John; Cohen, Omer; Bikov, Leonid; Hirsh, Itay

    2016-10-01

    CIRTEMO, SCD and Pixelteq have co-developed a miniature short-wave infrared (SWIR) hyperspectral snapshot imager utilizing Multivariate Optical Elements (MOEs). The resultant product may address many of the detection challenges facing multiple markets including commercial, medical, security and defense. This paper highlights the design process of developing MOEs for a targeted application, as well as the technological challenges faced and solutions developed for successful integration of a micro-patterned mosaic array to an InGaAs focal plane array.

  2. Design of extended viewing zone at autostereoscopic 3D display based on diffusing optical element

    NASA Astrophysics Data System (ADS)

    Kim, Min Chang; Hwang, Yong Seok; Hong, Suk-Pyo; Kim, Eun Soo

    2012-03-01

    In this paper, to realize a non-glasses type 3D display as next step from the current glasses-typed 3D display, it is suggested that a viewing zone is designed for the 3D display using DOE (Diffusing Optical Element). Viewing zone of proposed method is larger than that of the current parallax barrier method or lenticular method. Through proposed method, it is shown to enable the expansion and adjustment of the area of viewing zone according to viewing distance.

  3. Optical antenna gain. III - The effect of secondary element support struts on transmitter gain

    NASA Technical Reports Server (NTRS)

    Klein, B. J.; Degnan, J. J.

    1976-01-01

    The effect of a secondary-element spider support structure on optical antenna transmitter gain is analyzed. An expression describing the influence of the struts on the axial gain, in both the near and far fields, is derived as a function of the number of struts and their width. It is found that, for typical systems, the struts degrade the on-axis gain by less than 0.4 dB, and the first side-lobe level is not increased significantly. Contour plots have also been included to show the symmetry of the far-field distributions for three- and four-support members.

  4. James Webb Space Telescope Optical Telescope Element Mirror Development History and Results

    NASA Technical Reports Server (NTRS)

    Feinber, Lee D.; Clampin, Mark; Keski-Kuha, Ritva; Atkinson, Charlie; Texter, Scott; Bergeland, Mark; Gallagher, Benjamin B.

    2012-01-01

    In a little under a decade, the James Webb Space Telescope (JWST) program has designed, manufactured, assembled and tested 21 flight beryllium mirrors for the James Webb Space Telescope Optical Telescope Element. This paper will summarize the mirror development history starting with the selection of beryllium as the mirror material and ending with the final test results. It will provide an overview of the technological roadmap and schedules and the key challenges that were overcome. It will also provide a summary or the key tests that were performed and the results of these tests.

  5. Optical antenna gain. 3: The effect of secondary element support struts on transmitter gain.

    PubMed

    Klein, B J; Degnan, J J

    1976-04-01

    The effect of a secondary element spider support structure on optical antenna transmitter gain is analyzed. An expression describing the influence of the struts on the axial gain, in both the near and far fields, is derived as a function of the number of struts and their width. It is found that, for typical systems, the struts degrade the on-axis gain by less than 0.4 dB, and the first side-lobe level is not increased significantly. Contour plots have also been included to show the symmetry of the far-field distributions for three and four support members.

  6. Structural Health Monitoring Using High-Density Fiber Optic Strain Sensor and Inverse Finite Element Methods

    NASA Technical Reports Server (NTRS)

    Vazquez, Sixto L.; Tessler, Alexander; Quach, Cuong C.; Cooper, Eric G.; Parks, Jeffrey; Spangler, Jan L.

    2005-01-01

    In an effort to mitigate accidents due to system and component failure, NASA s Aviation Safety has partnered with industry, academia, and other governmental organizations to develop real-time, on-board monitoring capabilities and system performance models for early detection of airframe structure degradation. NASA Langley is investigating a structural health monitoring capability that uses a distributed fiber optic strain system and an inverse finite element method for measuring and modeling structural deformations. This report describes the constituent systems that enable this structural monitoring function and discusses results from laboratory tests using the fiber strain sensor system and the inverse finite element method to demonstrate structural deformation estimation on an instrumented test article

  7. Structural Anomaly Detection Using Fiber Optic Sensors and Inverse Finite Element Method

    NASA Technical Reports Server (NTRS)

    Quach, Cuong C.; Vazquez, Sixto L.; Tessler, Alex; Moore, Jason P.; Cooper, Eric G.; Spangler, Jan. L.

    2005-01-01

    NASA Langley Research Center is investigating a variety of techniques for mitigating aircraft accidents due to structural component failure. One technique under consideration combines distributed fiber optic strain sensing with an inverse finite element method for detecting and characterizing structural anomalies anomalies that may provide early indication of airframe structure degradation. The technique identifies structural anomalies that result in observable changes in localized strain but do not impact the overall surface shape. Surface shape information is provided by an Inverse Finite Element Method that computes full-field displacements and internal loads using strain data from in-situ fiberoptic sensors. This paper describes a prototype of such a system and reports results from a series of laboratory tests conducted on a test coupon subjected to increasing levels of damage.

  8. The Open Cluster Chemical Abundances and Mapping (OCCAM) Survey: Optical Extension for Neutron Capture Elements

    NASA Astrophysics Data System (ADS)

    Melendez, Matthew; O'Connell, Julia; Frinchaboy, Peter M.; Donor, John; Cunha, Katia M. L.; Shetrone, Matthew D.; Majewski, Steven R.; Zasowski, Gail; Pinsonneault, Marc H.; Roman-Lopes, Alexandre; Stassun, Keivan G.; APOGEE Team

    2017-01-01

    The Open Cluster Chemical Abundance & Mapping (OCCAM) survey is a systematic survey of Galactic open clusters using data primarily from the SDSS-III/APOGEE-1 survey. However, neutron capture elements are very limited in the IR region covered by APOGEE. In an effort to fully study detailed Galactic chemical evolution, we are conducting a high resolution (R~60,000) spectroscopic abundance analysis of neutron capture elements for OCCAM clusters in the optical regime to complement the APOGEE results. As part of this effort, we present Ba II, La II, Ce II and Eu II results for a few open clusters without previous abundance measurements using data obtained at McDonald Observatory with the 2.1m Otto Struve telescope and Sandiford Echelle Spectrograph.This work is supported by an NSF AAG grant AST-1311835.

  9. Optical properties of beam-steering elements utilizing volume holographic gratings

    NASA Astrophysics Data System (ADS)

    Butler, James Jay

    2000-06-01

    An optical beam steering element is a device that is used to control the direction in which a beam of light travels. We have investigated the optical properties of two classes of optical beam steering elements. The first type utilized the polarization dependence of the diffraction efficiency of volume holographic gratings. The second type utilized the fact that the diffraction efficiency of holograms imbibed with a nematic liquid crystal can be controlled by the application of an electric field. In both cases, elements with excellent switching contrasts were fabricated for operation in the visible and near infrared wavelength range including the commonly used telecommunications wavelength of 1.3μm. The holographic recording material that we have used is Polaroid Corporation's DMP-128 photopolymer. This material is porous after exposure and processing, a feature useful in two ways for this work. First, volume gratings with very large refractive index modulations, on the order of 0.2, can be fabricated using this material. Secondly, the pores can be filled with a nematic liquid crystal, resulting in electrically-switchable gratings. In our analysis of polarization-sensitive gratings we have employed several coupled wave theories, each with a different set of approximations. We have found that rigorous coupled wave theory must be used in predicting the diffractive properties of highly modulated volume gratings, where the effects of higher diffraction orders and form birefringence become important. In our analysis of the optical properties of electrically-switchable liquid crystal composite holograms, we have employed a theoretical analysis that treats the birefringent nature of the gratings. The results of Kogelnik theory that neglects the grating anisotropy, a two-wave theory that treats anisotropy, and a formulation of rigorous coupled wave theory that includes anisotropy were compared. We found it was necessary to include the effects of optical anisotropy to

  10. New tools for high-precision positioning of optical elements in high-NA microscope objectives

    NASA Astrophysics Data System (ADS)

    Heil, Joachim; Bauer, Tobias; Mueller, Willi; Sure, Thomas; Wesner, Joachim

    2004-02-01

    The precise positioning of the individual optical elements is essential for attaining diffraction limited performance in high-numerical-aperture (high-NA) microscope objectives. Tolerances are in the micron range or lower for high-end objectives, e.g. for broad-band scanning confocal applications, metrology objectives in general, and especially for deep ultraviolet (DUV) applications. The ever increasing demands on imaging performance ask for the continuous development and improvement of specialized measurement equipment for the production line. Our award-winning 150x/0.90-DUV-AT-infinity/0 objective for wafer inspection and metrology at 248nm employs air spacings in its doublets because of the instability of optical cements against DUV radiation. This comes however at the cost of a higher number of surfaces and even higher precision demands on their geometry, orientation and positioning. We present several tools enabling us to meet these requirements. A Fourier transform fringe analysis scheme is adapted to high-NA Fizeau interferometry for surface characterization. A white light Mirau interferometer for dimensional measurements on lens groups with sub-μm resolution enables us to keep surface distance errors lower than 2 μm. Residual aberrations of the objective are compensated for by translating special correction elements under observation of the wave-front using a DUV-Twyman-Green interferometer, which also incorporates a 903nm branch for the parfocal adjustment of the infrared (IR) autofocus feature of the objective. To adjust the shifting element for the elimination of on-axis coma, we compute an artificial (real-time) star test from the interferogram, allowing interactive manipulations of the element while monitoring their influence on the point spread function (PSF).

  11. A 16 element quasi-optical FET oscillator power combining array with external injection locking

    NASA Astrophysics Data System (ADS)

    Birkeland, Joel; Itoh, Tatsuo

    1992-03-01

    The authors present analysis, design and experimental results of a 16 element planar oscillator array for quasi-optical power combining. Each element in the array consists of a single FET oscillator with an input port for injection of the locking signal, and an output port which is connected to a patch radiator. The array is synchronized using a 16-way power dividing network which distributes the locking signal to the oscillating elements. The array is constructed using a two-sided microstrip configuration, with the oscillators and feed network on one side of a ground plane, and the patch radiators on the opposite side. An effective radiated power (ERP) of 28.2 W CW with an isotropic conversion gain of 9.9 dB was measured at 6 GHz. For an injected power of 10.3 dBm, a locking range of 453 MHz at a center frequency of 6.015 GHz was obtained; a bandwidth of 7.5 percent. Because of the simple nature of the individual oscillator elements, this approach is well suited to MMIC implementation.

  12. Magneto-optical investigation of the shape anisotropy of individual micron-sized magnetic elements

    NASA Astrophysics Data System (ADS)

    Sebastian, T.; Conca, A.; Wolf, G.; Schultheiss, H.; Leven, B.; Hillebrands, B.

    2011-10-01

    In this work, the anisotropy of individual microstructured magnetic elements has been investigated. The investigated elements are of elliptical shape with different sizes and aspect ratios (AR), structured from a 5-nm-thick permalloy (Ni80 Fe20) film. For the measurements, a new magneto-optical Kerr effect (MOKE) magnetometer was used. To allow for the investigation of individual microstructured elements, a micro-focused probing laser beam (spatial resolution ≈1μm) has been combined with a self-stabilizing positioning system of high accuracy, including a rotating unit. Hysteresis loops can be taken for varying orientation of the symmetry axes of the magnetic elements relative to the applied field. For the characterization of the anisotropy, the coercive field as a function of the magnetization direction is extracted from the corresponding hysteresis loops. These results make a quantitative and systematic study of the influence of the shape anisotropy on the magnetic behavior of microstructures possible. The experimental data has been compared to an extended Stoner-Wohlfarth model.

  13. Use of surfactants to reduce the driving voltage of switchable optical elements based on electrowetting.

    PubMed

    Roques-Carmes, Thibault; Gigante, Alexandra; Commenge, Jean-Marc; Corbel, Serge

    2009-11-03

    The advantage of using electrowetting as a novel principle for a reflective display has been previously demonstrated. The principle is based on the controlled two-dimensional movement of an oil/water interface across a hydrophobic fluoropolymer insulator. The main objective of this paper is to show experimentally the influence of surfactants on the electro-optic behavior of a single electrowetting pixel. The concentration and type of nonionic surfactant (Tween 80 and Span 20) have been varied. The experimental data are compared with calculations from the electro-optic model developed previously. The electro-optic performance is significantly affected by the nature and the concentration of surfactant. In the presence of Tween, at concentrations lower than the critical micelle concentration (CMC), and mixtures of Tween and Span the electro-optic behavior can be related to the interfacial tension. When decreasing the oil/water interfacial tension, the amplitude of the driving voltage required for obtaining a given oil displacement decreases and the switching curve becomes steeper. These effects can be accurately reproduced by means of the previously developed electro-optic model. Mixtures of Tween and Span produce a significant synergetic reduction of the driving voltage. For Tween concentrations higher than the CMC and Span, a strong disagreement is observed between the previously developed model and experimental data. Here a new physical model is reported that describes the electro-optic behavior of electrowetting-based optical elements in the presence of surfactants. The model takes into account the actual voltage used to control the liquid movement in electrowetting (lower than the applied voltage), the amount of surfactant adsorbed at the decane/water interface, and the dipole moment of the surfactant molecules. The calculated results are in very good agreement with experimental data without employing fitting parameters. The dipoles interact with the applied

  14. Enhancement of the Performance of Perovskite Solar Cells, LEDs, and Optical Amplifiers by Anti-Solvent Additive Deposition.

    PubMed

    Ngo, Thi Tuyen; Suarez, Isaac; Antonicelli, Gabriella; Cortizo-Lacalle, Diego; Martinez-Pastor, Juan P; Mateo-Alonso, Aurelio; Mora-Sero, Ivan

    2017-02-01

    The efficiency of perovskite optoelectronic devices is increased by a novel method; its suitability for perovskite solar cells, light-emitting diodes, and optical amplifiers is demonstrated. The method is based on the introduction of organic additives during the anti-solvent step in the perovskite thin-film deposition process. Additives passivate grain boundaries reducing non-radiative recombination. The method can be easily extended to other additives.

  15. Long-term laser induced contamination tests of optical elements under vacuum at 351nm

    NASA Astrophysics Data System (ADS)

    Leinhos, Uwe; Mann, Klaus; Bayer, Armin; Dette, Jens-Oliver; Schöneck, Matthias; Endemann, Martin; Wernham, Denny; Petazzi, Federico; Tighe, Adrian; Alves, Jorge; Thibault, Dominique

    2010-11-01

    Photon-induced contamination of optical surfaces is a major obstacle for space-bound laser applications. At Laser-Laboratorium Göttingen, a setup was developed that allows monitoring transmission, reflection and fluorescence of laser-irradiated optical components under well-controlled vacuum conditions, in order to assess their possible optical degradation due to radiation-induced contaminant deposition in orbit. In cooperation with the European Space Agency ESA optical elements for the ADM-Aelolus mission were investigated. In order to perform global wind-profile observation based on Doppler-LIDAR, the satellite ADM-Aelolus will be launched in 2011 and injected into an orbit 400 km above Earth's surface. ADM-Aeolus will be the first satellite ever that is equipped with a UV-laser (emitting at a wavelength of 355 nm) and a reflector telescope. For both high-reflecting mirrors and an anti-reflective coated windows long-term irradiation tests (up to 500 million laser pulses per test run) were performed at a base pressure < 10-9 mbar, using a XeF excimer laser (λ=351 nm, repetition rate 1kHz). At this, samples of polymers used inside the satellite (insulators for cabling, adhesives, etc.) were installed into the chamber, and the interaction of their degassing with the sample surfaces under laser irradiation was investigated. Optical degradation associated with contaminant adsorption was detected on the irradiated sample sites as a function of various parameters, including pulse repetition rate, view factor and coating material

  16. Computational optical palpation: micro-scale force mapping using finite-element methods (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Wijesinghe, Philip; Sampson, David D.; Kennedy, Brendan F.

    2016-03-01

    Accurate quantification of forces, applied to, or generated by, tissue, is key to understanding many biomechanical processes, fabricating engineered tissues, and diagnosing diseases. Many techniques have been employed to measure forces; in particular, tactile imaging - developed to spatially map palpation-mimicking forces - has shown potential in improving the diagnosis of cancer on the macro-scale. However, tactile imaging often involves the use of discrete force sensors, such as capacitive or piezoelectric sensors, whose spatial resolution is often limited to 1-2 mm. Our group has previously presented a type of tactile imaging, termed optical palpation, in which the change in thickness of a compliant layer in contact with tissue is measured using optical coherence tomography, and surface forces are extracted, with a micro-scale spatial resolution, using a one-dimensional spring model. We have also recently combined optical palpation with compression optical coherence elastography (OCE) to quantify stiffness. A main limitation of this work, however, is that a one-dimensional spring model is insufficient in describing the deformation of mechanically heterogeneous tissue with uneven boundaries, generating significant inaccuracies in measured forces. Here, we present a computational, finite-element method, which we term computational optical palpation. In this technique, by knowing the non-linear mechanical properties of the layer, and from only the axial component of displacement measured by phase-sensitive OCE, we can estimate, not only the axial forces, but the three-dimensional traction forces at the layer-tissue interface. We use a non-linear, three-dimensional model of deformation, which greatly increases the ability to accurately measure force and stiffness in complex tissues.

  17. Subject-specific finite element model with an optical tracking system in total hip replacement surgery.

    PubMed

    Miles, Brad; Kolos, Elizabeth; Walter, William L; Appleyard, Richard; Li, Qing; Chen, Youngang; Ruys, Andrew J

    2015-04-01

    Intra-operative peri-prosthetic femoral fractures are a significant concern in total hip arthroplasty and can occur at any time during surgery, with the highest incidence during implant insertion. This study combines subject-specific finite element analysis modeling with an optical tracking system to characterize the resultant strain in the bone and results of impaction during total hip replacement surgery. The use of ABG II femoral stem (Stryker Orthopaedics, Mahwah, NJ, USA) in the model yielded the following results. Hammer velocity was measured experimentally using a three-dimensional optical tracking system and these data were input into the finite element analysis model so that intra-operative loading scenario could be simulated. A quasi-static explicit simulation and a dynamic loading step using two implant-bone interface friction (0.1 and 0.4 friction coefficients) states were simulated. The maximum swing velocity of a mallet was experimentally measured at 1.5 m/s and occurred just before impaction of the hammer with implant introducer. Two friction states resulted in different results with the lower friction coefficient generating higher strains in the anterior regions of the model and higher displacement of the implant with respect to the femur when compared to the high friction state.

  18. Iterative Fourier transform algorithm: different approaches to diffractive optical element design

    NASA Astrophysics Data System (ADS)

    Skeren, Marek; Richter, Ivan; Fiala, Pavel

    2002-10-01

    This contribution focuses on the study and comparison of different design approaches for designing phase-only diffractive optical elements (PDOEs) for different possible applications in laser beam shaping. Especially, new results and approaches, concerning the iterative Fourier transform algorithm, are analyzed, implemented, and compared. Namely, various approaches within the iterative Fourier transform algorithm (IFTA) are analyzed for the case of phase-only diffractive optical elements with quantizied phase levels (either binary or multilevel structures). First, the general scheme of the IFTA iterative approach with partial quantization is briefly presented and discussed. Then, the special assortment of the general IFTA scheme is given with respect to quantization constraint strategies. Based on such a special classification, the three practically interesting approaches are chosen, further-analyzed, and compared to eachother. The performance of these algorithms is compared in detail in terms of the signal-to-noise ratio characteristic developments with respect to the numberof iterations, for various input diffusive-type objects chose. Also, the performance is documented on the complex spectra developments for typical computer reconstruction results. The advantages and drawbacks of all approaches are discussed, and a brief guide on the choice of a particular approach for typical design tasks is given. Finally, the two ways of amplitude elimination within the design procedure are considered, namely the direct elimination and partial elimination of the amplitude of the complex hologram function.

  19. Optical element for full spectral purity from IR-generated EUV light sources

    NASA Astrophysics Data System (ADS)

    van den Boogaard, A. J. R.; Louis, E.; van Goor, F. A.; Bijkerk, F.

    2009-03-01

    Laser produced plasma (LLP) sources are generally considered attractive for high power EUV production in next generation lithography equipment. Such plasmas are most efficiently excited by the relatively long, infrared wavelengths of CO2-lasers, but a significant part of the rotational-vibrational excitation lines of the CO2 radiation will be backscattered by the plasma's critical density surface and consequently will be present as parasitic radiation in the spectrum of such sources. Since most optical elements in the EUV collecting and imaging train have a high reflection coefficient for IR radiation, undesirable heating phenomena at the resist level are likely to occur. In this study a completely new principle is employed to obtain full separation of EUV and IR radiation from the source by a single optical component. While the application of a transmission filter would come at the expense of EUV throughput, this technique potentially enables wavelength separation without loosing reflectance compared to a conventional Mo/Si multilayer coated element. As a result this method provides full spectral purity from the source without loss in EUV throughput. Detailed calculations on the principal of functioning are presented.

  20. Analysis of the laser powder bed fusion additive manufacturing process through experimental measurement and finite element modeling

    NASA Astrophysics Data System (ADS)

    Dunbar, Alexander Jay

    The objective in this work is to provide rigourous experimental measurements to aid in the development of laser powder bed fusion (LPBF) additive manufacturing (AM). A specialized enclosed instrumented measurement system is designed to provide in situ experimental measurements of temperature and distortion. Experiments include comparisons of process parameters, materials and LPBF machines. In situ measurements of distortion and temperature made throughout the build process highlight inter-layer distortion effects previously undocumented for laser powder bed fusion. Results from these experiments are also be implemented in the development and validation of finite element models of the powder bed build process. Experimental analysis is extended from small-scale to larger part-scale builds where experimental post-build measurements are used in analysis of distortion profiles. Experimental results provided from this study are utilized in the validation of a finite element model capable of simulating production scale parts. The validated finite element model is then implemented in the analysis of the part to provide information regarding the distortion evolution process. A combination of experimental measurements and simulation results are used to identify the mechanism that results in the measured distortion profile for this geometry. Optimization of support structure primarily focuses on the minimization of material use and scan time, but no information regarding failure criteria for support structure is available. Tensile test samples of LPBF built support structure are designed, built, and tested to provide measurements of mechanical properties of the support structure. Experimental tests show that LPBF built support structure has only 30-40% of the ultimate tensile strength of solid material built in the same machine. Experimental measurement of LPBF built support structure provides clear failure criteria to be utilized in the future design and implementation of

  1. Fabrication of x-ray diffractive optical elements for laser fusion applications

    NASA Astrophysics Data System (ADS)

    Xie, Changqing; Zhu, Xiaoli; Li, Hailiang; Niu, Jiebin; Hua, Yilei; Shi, Lina

    2013-03-01

    We review our recent progress on the fabrication of x-ray diffractive optical elements (DOEs) by combining complementary advantages of electron beam, x-ray, and proximity optical lithography. First, an electron beam lithography tool with an accelerating voltage of 100 kV is used to expose initial x-ray mask based on SiC membrane with a low aspect ratio. Second, x-ray lithography is used to replicate x-ray DOEs and amplify the aspect ratio up to 14:1. Third, proximity optical lithography is used to fabricate a large-scale gold mesh as the supporting structures. We demonstrate that this method can achieve high aspect ratio metal nanometer structures without the need of a complicated multilayer resist process. A large number of x-ray DOEs have been fabricated with feature sizes down to 100 nm for the purpose of laser plasma fusion applications. Among them, the ninth-order diffraction peak on the positive side of the zeroth order can be observed for both 3333 and 5000 lines/mm x-ray gold transmission gratings.

  2. Comparison of simulated quenching algorithms for design of diffractive optical elements.

    PubMed

    Liu, J S; Caley, A J; Waddie, A J; Taghizadeh, M R

    2008-02-20

    We compare the performance of very fast simulated quenching; generalized simulated quenching, which unifies classical Boltzmann simulated quenching and Cauchy fast simulated quenching; and variable step size simulated quenching. The comparison is carried out by applying these algorithms to the design of diffractive optical elements for beam shaping of monochromatic, spatially incoherent light to a tightly focused image spot, whose central lobe should be smaller than the geometrical-optics limit. For generalized simulated quenching we choose values of visiting and acceptance shape parameters recommended by other investigators and use both a one-dimensional and a multidimensional Tsallis random number generator. We find that, under our test conditions, variable step size simulated quenching, which generates each parameter's new states based on the acceptance ratio instead of a certain theoretical probability distribution, produces the best results. Finally, we demonstrate experimentally a tightly focused image spot, with a central lobe 0.22-0.68 times the geometrical-optics limit and a relative sidelobe intensity 55%-60% that of the central maximum intensity.

  3. Extended volume and surface scatterometer for optical characterization of 3D-printed elements

    NASA Astrophysics Data System (ADS)

    Dannenberg, Florian; Uebeler, Denise; Weiß, Jürgen; Pescoller, Lukas; Weyer, Cornelia; Hahlweg, Cornelius

    2015-09-01

    The use of 3d printing technology seems to be a promising way for low cost prototyping, not only of mechanical, but also of optical components or systems. It is especially useful in applications where customized equipment repeatedly is subject to immediate destruction, as in experimental detonics and the like. Due to the nature of the 3D-printing process, there is a certain inner texture and therefore inhomogeneous optical behaviour to be taken into account, which also indicates mechanical anisotropy. Recent investigations are dedicated to quantification of optical properties of such printed bodies and derivation of corresponding optimization strategies for the printing process. Beside mounting, alignment and illumination means, also refractive and reflective elements are subject to investigation. The proposed measurement methods are based on an imaging nearfield scatterometer for combined volume and surface scatter measurements as proposed in previous papers. In continuation of last year's paper on the use of near field imaging, which basically is a reflective shadowgraph method, for characterization of glossy surfaces like printed matter or laminated material, further developments are discussed. The device has been extended for observation of photoelasticity effects and therefore homogeneity of polarization behaviour. A refined experimental set-up is introduced. Variation of plane of focus and incident angle are used for separation of various the images of the layers of the surface under test, cross and parallel polarization techniques are applied. Practical examples from current research studies are included.

  4. Uniformity of reshaped beam by diffractive optical elements with light-emitted diode illumination

    NASA Astrophysics Data System (ADS)

    Chen, Mengzhu; Gu, Huarong; Wang, Qixia; Tan, Qiaofeng

    2015-10-01

    Due to its low energy consumption, high efficiency and fast switching speed, light-emitted diode (LED) has been used as a new light source in optical wireless communication. To ensure uniform lighting and signal-to-noise ratio (SNR) during the data transmission, diffractive optical elements (DOEs) can be employed as optical antennas. Different from laser, LED has a low temporal and spatial coherence. And its impacts upon the far-field diffraction patterns of DOEs remain unclear. Thus the mathematical models of far-field diffraction intensity for LED with a spectral bandwidth and source size are first derived in this paper. Then the relation between source size and uniformity of top-hat beam profile for LEDs either considering the spectral bandwidth or not are simulated. The results indicate that when the size of LED is much smaller than that of reshaped beam, the uniformity of reshaped beam obtained by light source with a spectral bandwidth is significantly better than that by a monochromatic light. However, once the size is larger than a certain threshold value, the uniformity of reshaped beam of two LED models are almost the same, and the influence introduced by spectral bandwidth can be ignored. Finally the reshaped beam profiles are measured by CCD camera when the areas of LED are 0.5×0.5mm2 and 1×1mm2. And the experimental results agree with the simulations.

  5. High numerical aperture diffractive optical elements for neutral atom quantum computing

    NASA Astrophysics Data System (ADS)

    Young, A. L.; Kemme, S. A.; Wendt, J. R.; Carter, T. R.; Samora, S.

    2013-03-01

    The viability of neutral atom based quantum computers is dependent upon scalability to large numbers of qubits. Diffractive optical elements (DOEs) offer the possibility to scale up to many qubit systems by enabling the manipulation of light to collect signal or deliver a tailored spatial trapping pattern. DOEs have an advantage over refractive microoptics since they do not have measurable surface sag, making significantly larger numerical apertures (NA) accessible with a smaller optical component. The smaller physical size of a DOE allows the micro-lenses to be placed in vacuum with the atoms, reducing aberration effects that would otherwise be introduced by the cell walls of the vacuum chamber. The larger collection angle accessible with DOEs enable faster quantum computation speeds. We have designed a set of DOEs for collecting the 852 nm fluorescence from the D2 transition in trapped cesium atoms, and compare these DOEs to several commercially available refractive micro-lenses. The largest DOE is able to collect over 20% of the atom's radiating sphere whereas the refractive micro-optic is able to collect just 8% of the atom's radiating sphere.

  6. Adaptive finite element methods for the solution of inverse problems in optical tomography

    NASA Astrophysics Data System (ADS)

    Bangerth, Wolfgang; Joshi, Amit

    2008-06-01

    Optical tomography attempts to determine a spatially variable coefficient in the interior of a body from measurements of light fluxes at the boundary. Like in many other applications in biomedical imaging, computing solutions in optical tomography is complicated by the fact that one wants to identify an unknown number of relatively small irregularities in this coefficient at unknown locations, for example corresponding to the presence of tumors. To recover them at the resolution needed in clinical practice, one has to use meshes that, if uniformly fine, would lead to intractably large problems with hundreds of millions of unknowns. Adaptive meshes are therefore an indispensable tool. In this paper, we will describe a framework for the adaptive finite element solution of optical tomography problems. It takes into account all steps starting from the formulation of the problem including constraints on the coefficient, outer Newton-type nonlinear and inner linear iterations, regularization, and in particular the interplay of these algorithms with discretizing the problem on a sequence of adaptively refined meshes. We will demonstrate the efficiency and accuracy of these algorithms on a set of numerical examples of clinical relevance related to locating lymph nodes in tumor diagnosis.

  7. Manufacturing of freeform micro-optical elements by mask-less laser direct write lithography and replication by imprinting

    NASA Astrophysics Data System (ADS)

    Kuna, L.; Leiner, C.; Ruttloff, S.; Nemitz, W.; Reil, F.; Hartmann, P.; Wenzl, F. P.; Sommer, C.

    2016-09-01

    Today, freeform micro-optical structures are desired components in many photonic and optical applications such as lighting and detection systems due to their compactness, ease of system integration and superior optical performance. The high complexity of a freeform structure's arbitrary surface profile and the need for high throughput upon fabrication require novel approaches for their integration into a manufacturing process. For the fabrication of polymer freeform optics, in this contribution we discuss two principal technologies, mask-less laser direct write lithography (MALA) and replication from the as-fabricated master by imprinting. We show the high flexibility in design and rapid-prototyping of freeform optical microstructures that can be achieved by such an approach. First, the original structures known as masters are fabricated using MALA. Because of the specific requirements on shape and height (>50μm) of the microstructures, laser writing and photoresist processing have to be performed within a narrow range of fabrication parameters. Subsequently, UV-soft lithography based replication is used for serial production of the freeform micro-optical elements within a batch process. Aided by profilometry, optical microscopy and atomic force microscopy, the fidelity of the fabricated freeform microoptical elements to the design is characterised. Finally, the light intensity distribution on a target plane caused by the freeform micro-optical element illuminated with an LED is determined and compared with the predicted one.

  8. A radio/optical reference frame. 5: Additional source positions in the mid-latitude southern hemisphere

    NASA Technical Reports Server (NTRS)

    Russell, J. L.; Reynolds, J. E.; Jauncey, D. L.; De Vegt, C.; Zacharias, N.; Ma, C.; Fey, A. L.; Johnston, K. J.; Hindsley, R.; Hughes, J. A.

    1994-01-01

    We report new accurate radio position measurements for 30 sources, preliminary positions for two sources, improved radio postions for nine additional sources which had limited previous observations, and optical positions and optical-radio differences for six of the radio sources. The Very Long Baseline Interferometry (VLBI) observations are part of the continuing effort to establish a global radio reference frame of about 400 compact, flat spectrum sources, which are evenly distributed across the sky. The observations were made using Mark III data format in four separate sessions in 1988-89 with radio telescopes at Tidbinbilla, Australia, Kauai, USA, and Kashima, Japan. We observed a total of 54 sources, including ten calibrators and three which were undetected. The 32 new source positions bring the total number in the radio reference frame catalog to 319 (172 northern and 147 southern) and fill in the zone -25 deg greater than delta greater than -45 deg which, prior to this list, had the lowest source density. The VLBI positions have an average formal precision of less than 1 mas, although unknown radio structure effects of about 1-2 mas may be present. The six new optical postion measurements are part of the program to obtain positions of the optical counterparts of the radio reference frame source and to map accurately the optical on to the radio reference frames. The optical measurements were obtained from United States Naval Observatory (USNO) Black Birch astrograph plates and source plates from the AAT, and Kitt Peak National Observatory (KPNO) 4 m, and the European Southern Observatory (ESO) Schmidt. The optical positions have an average precision of 0.07 sec, mostly due to the zero point error when adjusted to the FK5 optical frame using the IRS catalog. To date we have measured optical positions for 46 sources.

  9. Additional optical photometry of the recurrent nova M31N 1990-10a during its 2016 eruption

    NASA Astrophysics Data System (ADS)

    Goranskij, V.; Barsukova, E.; Henze, M.

    2016-08-01

    We report additional optical measurements of the declining light curve of the recurrent nova M31N 1990-10a (see ATels #9276,#9280,#9281,#9383,#9386). All data were obtained with the 50-cm Maksutov meniscus telescope of the Crimean Astronomical Station of the Moscow University.

  10. Capillary Optics Based X-Ray Micro-Imaging Elemental Analysis

    NASA Astrophysics Data System (ADS)

    Hampai, D.; Dabagov, S. B.; Cappuccio, G.; Longoni, A.; Frizzi, T.; Cibin, G.

    2010-04-01

    A rapidly developed during the last few years micro-X-ray fluorescence spectrometry (μXRF) is a promising multi-elemental technique for non-destructive analysis. Typically it is rather hard to perform laboratory μXRF analysis because of the difficulty of producing an original small-size X-ray beam as well as its focusing. Recently developed for X-ray beam focusing polycapillary optics offers laboratory X-ray micro probes. The combination of polycapillary lens and fine-focused micro X-ray tube can provide high intensity radiation flux on a sample that is necessary in order to perform the elemental analysis. In comparison to a pinhole, an optimized "X-ray source-op tics" system can result in radiation density gain of more than 3 orders by the value. The most advanced way to get that result is to use the confocal configuration based on two X-ray lenses, one for the fluorescence excitation and the other for the detection of secondary emission from a sample studied. In case of X-ray capillary microfocusing a μXRF instrument designed in the confocal scheme allows us to obtain a 3D elemental mapping. In this work we will show preliminary results obtained with our prototype, a portable X-ray microscope for X-ray both imaging and fluorescence analysis; it enables μXRF elemental mapping simultaneously with X-ray imaging. A prototype of compact XRF spectrometer with a spatial resolution less than 100 μm has been designed.

  11. Significant sensitivity improvement of alternating current driven-liquid discharge by using formic acid medium for optical determination of elements.

    PubMed

    Xiao, Qing; Zhu, Zhenli; Zheng, Hongtao; He, Haiyang; Huang, Chunying; Hu, Shenghong

    2013-03-15

    A method has been developed to improve the performance of alternating-current electrolyte atmospheric liquid discharge (ac-EALD) optical emission spectrometry for the determination of elements. Significant enhancement of emission intensity was achieved by adding organic substance into the nitric acid electrolyte solutions. Under the optimized conditions, 3% (v/v) formic acid in nitric acid (pH 1.0) produced 13 times enhancement for Ag and 7% (v/v) formic acid resulted in 17 times enhancement for Cd. The emission of Pb was even enhanced 78 times in the presence of 3% formic acid. In addition, the signal stability was also improved compared with that in the absence of organic substances. Repeatability was 0.8% for 0.1 mg L(-1) Ag, 0.7% for 0.2 mg L(-1) Cd and 2.6% for 1 mg L(-1) Pb standard solutions (n=5). The limits of detection of Ag, Cd and Pb were 1, 17 and 45 μg L(-1), respectively. The accuracy of the method was demonstrated by determination of elements in simulated natural water samples (GBW(E)080402 and GBW(E)080399).

  12. Heavy Element Abundances in Planetary Nebulae from Deep Optical Echelle Spectroscopy

    NASA Astrophysics Data System (ADS)

    Mashburn, Amanda; Sterling, Nicholas C.; Dinerstein, Harriet L.; Garofali, Kristen; Jensema, Rachael; Turbyfill, Amanda; Wieser, Hannah-Marie N.; Reed, Evan C.; Redfield, Seth

    2016-01-01

    We present the abundances of neutron(n)-capture elements (atomic number Z > 30) and iron determined from deep optical echelle spectroscopy of 14 Galactic planetary nebulae (PNe). The spectra were obtained with the 2D-coudé spectrograph on the 2.7-m Harlan J. Smith telescope at McDonald Observatory. The abundances of n-capture elements can be enhanced in PNe due to slow n-capture nucleosynthesis in the progenitor asymptotic giant branch (AGB) stars. The high spectral resolution of these data (R = 36,700) allow most n-capture element emission lines to be resolved from other nebular and telluric features. We detect Kr in all of the observed PNe (with multiple ions detected in several objects), while Br, Rb, and Xe were each detected in 4--5 objects. Using the new Kr ionization correction factors (ICFs) of Sterling et al. (2015, ApJS, 218, 25), we find [Kr/O] abundances ranging from 0.05 to 1.1 dex. We utilize approximate ICFs for the other n-capture elements, and find slightly lower enrichments for Br and Rb (-0.1 to 0.7 dex), while Xe is enhanced relative to solar by factors of two to 30. The [Xe/Kr] ratios range from -0.3 to 1.4 dex, indicating a significant range in neutron exposures in PN progenitor stars. Interestingly, the largest [Xe/Kr] ratio is found in the thick-disk PN NGC 6644, which has a lower metallicity than the other observed PNe. We detect iron emission lines in all but one target. Fe can be depleted into dust grains in ionized nebulae, and its abundance thus provides key information regarding dust-to-gas ratios and grain destruction processes. We find that [Fe/O] ranges from -1.3 to -0.7 dex in the observed PNe, a smaller spread of depletion factors than found in recent studies (Delgado-Inglada & Rodriguez 2014, ApJ, 784, 173) though this may be due in part to our smaller sample. These data are part of a larger study of heavy elements in PNe, which will provide more accurate determinations of n-capture element abundances than previous estimates in

  13. Can the Isolated-Elements Strategy Be Improved by Targeting Points of High Cognitive Load for Additional Practice?

    ERIC Educational Resources Information Center

    Ayres, Paul

    2013-01-01

    Reducing problem complexity by isolating elements has been shown to be an effective instructional strategy. Novices, in particular, benefit from learning from worked examples that contain partially interacting elements rather than worked examples that provide full interacting elements. This study investigated whether the isolating-elements…

  14. Reasoning Modes, Knowledge Elements and Their Interplay in Optics Problem-Solving

    NASA Astrophysics Data System (ADS)

    Undreiu, Adriana; Schuster, David; Adams, Betty

    2008-10-01

    We have investigated how students tackle problems in geometric optics involving ray construction, to try to understand the nature and origin of the surprisingly wide variety of students' solution attempts. We find that students use various reasoning modes and knowledge elements in conjunction. Their thinking may usefully be described as an interplay of principle-based and case-based reasoning, drawing on a knowledge mixture of basic principles, procedures, specific cases and recalled result features. Even though we usually present solutions and teach problem solving as a systematic application of principles, real cognition is more complex. Associative thinking in terms of prior cases seems to be a strong natural tendency of both novices and experts. However, novices are not easily able to discriminate the specific from the general, and tend to lack epistemic awareness and metacognitive skills. Our research findings will be illustrated by examples of student thinking on a basic reflection problem. Implications for learning and instruction are discussed.

  15. Characterization of volume holographic optical elements recorded in Bayfol HX photopolymer for solar photovoltaic applications.

    PubMed

    Marín-Sáez, Julia; Atencia, Jesús; Chemisana, Daniel; Collados, María-Victoria

    2016-03-21

    Volume Holographic Optical Elements (HOEs) present interesting characteristics for photovoltaic applications as they can select spectrum for concentrating the target bandwidth and avoiding non-desired wavelengths, which can cause the decrease of the performance on the cell, for instance by overheating it. Volume HOEs have been recorded on Bayfol HX photopolymer to test the suitability of this material for solar concentrating photovoltaic systems. The HOEs were recorded at 532 nm and provided a dynamic range, reaching close to 100% efficiency at 800 nm. The diffracted spectrum had a FWHM of 230 nm when illuminating at Bragg angle. These characteristics prove HOEs recorded on Bayfol HX photopolymer are suitable for concentrating solar light onto photovoltaic cells sensitive to that wavelength range.

  16. A sensing element based on a bent and elongated grooved polymer optical fiber.

    PubMed

    Lu, Wei-Hua; Chen, Li-Wen; Xie, Wen-Fu; Chen, Yung-Chuan

    2012-01-01

    An experimental and numerical investigation is performed into the power loss induced in grooved polymer optical fibers (POFs) subjected to combined bending and elongation deformations. The power loss is examined as a function of both the groove depth and the bend radius. An elastic-plastic three-dimensional finite element model is constructed to simulate the deformation in the grooved region of the deformed specimens. The results indicate that the power loss increases significantly with an increasing bending displacement or groove depth. Specifically, the power loss increases to as much as 12% given a groove depth of 1.1 mm and a bending displacement of 10 mm. Based on the experimental results, an empirical expression is formulated to relate the power loss with the bending displacement for a given groove depth. It is shown that the difference between the estimated power loss and the actual power loss is less than 2%.

  17. Design and performance of coded aperture optical elements for the CESR-TA x-ray beam size monitor

    NASA Astrophysics Data System (ADS)

    Alexander, J. P.; Chatterjee, A.; Conolly, C.; Edwards, E.; Ehrlichman, M. P.; Flanagan, J. W.; Fontes, E.; Heltsley, B. K.; Lyndaker, A.; Peterson, D. P.; Rider, N. T.; Rubin, D. L.; Seeley, R.; Shanks, J.

    2014-12-01

    We describe the design and performance of optical elements for an x-ray beam size monitor (xBSM), a device measuring e+ and e- beam sizes in the CESR-TA storage ring. The device can measure vertical beam sizes of 10 - 100 μm on a turn-by-turn, bunch-by-bunch basis at e± beam energies of ~ 2 - 5 GeV. x-rays produced by a hard-bend magnet pass through a single- or multiple-slit (coded aperture) optical element onto a detector. The coded aperture slit pattern and thickness of masking material forming that pattern can both be tuned for optimal resolving power. We describe several such optical elements and show how well predictions of simple models track measured performances.

  18. Detection and quantification of additives (urea, biuret and poultry litter) in alfalfas by NIR spectroscopy with fibre-optic probe.

    PubMed

    González-Martín, Inmaculada; Hernández-Hierro, José Miguel

    2008-09-15

    The additives (urea, biuret and poultry litter) present in alfalfa, which contribute non-proteic nitrogen, were analysed using near infrared spectroscopy (NIRS) technology together with a remote reflectance fibre-optic probe. We used 75 samples of known alfalfa without additives and 75 samples with each of the additives, urea (0.01-10%), biuret (0.01-10%) and poultry litter (1-25%). Using the discriminant partial least squares (DPLS) algorithm, the presence or absence of the additives urea, biuret and poultry litter is classified and predicted with a high prediction rate of 96.9%, 100% and 100%, obtaining the equations of discrimination for each additive. The regression method employed for the quantification was modified partial least squares (MPLS). The equations were developed using the fibre-optic probe to determine the content of urea, biuret and poultry litter with multiple correlation coefficients (RSQ) and prediction corrected standard errors (SEP (C)) of 0.990, 0.28% for urea, 0.991, 0.29% for biuret and 0.925, 2.08% for poultry litter. The work permits the instantaneous and simultaneous prediction and determination of urea, biuret and poultry litter in alfalfas, applying the fibre-optic directly on the ground samples of alfalfa.

  19. Invited Review Article: Review of post-process optical form metrology for industrial-grade metal additive manufactured parts.

    PubMed

    Stavroulakis, P I; Leach, R K

    2016-04-01

    The scope of this review is to investigate the main post-process optical form measurement technologies available in industry today and to determine whether they are applicable to industrial-grade metal additive manufactured parts. An in-depth review of the operation of optical three-dimensional form measurement technologies applicable to metal additive manufacturing is presented, with a focus on their fundamental limitations. Looking into the future, some alternative candidate measurement technologies potentially applicable to metal additive manufacturing will be discussed, which either provide higher accuracy than currently available techniques but lack measurement volume, or inversely, which operate in the appropriate measurement volume but are not currently accurate enough to be used for industrial measurement.

  20. Invited Review Article: Review of post-process optical form metrology for industrial-grade metal additive manufactured parts

    NASA Astrophysics Data System (ADS)

    Stavroulakis, P. I.; Leach, R. K.

    2016-04-01

    The scope of this review is to investigate the main post-process optical form measurement technologies available in industry today and to determine whether they are applicable to industrial-grade metal additive manufactured parts. An in-depth review of the operation of optical three-dimensional form measurement technologies applicable to metal additive manufacturing is presented, with a focus on their fundamental limitations. Looking into the future, some alternative candidate measurement technologies potentially applicable to metal additive manufacturing will be discussed, which either provide higher accuracy than currently available techniques but lack measurement volume, or inversely, which operate in the appropriate measurement volume but are not currently accurate enough to be used for industrial measurement.

  1. Research of the new optical diffractive super-resolution element of the two-photon microfabrication

    NASA Astrophysics Data System (ADS)

    Wei, Peng; Zhu, Yu; Duan, Guanghong

    2006-11-01

    The new optical diffractive superresolution element (DSE) is being applied to improve the microfabrication radial superresolution in the two-photon three-dimension (3D) microfabrication system, which appeared only a few years ago and can provide the ability to confine photochemical and physical reactions to the order of laser wavelength in three dimensions. The design method of the DSE is that minimizing M if the lowest limit S l of the S and the highest limit G u of the G is set, where Liu [1] explained the definition of the S, M and G. Simulation test result proved that the microfabrication radial superresolution can be improved by the new optical DSE. The phenomenon can only be interpreted as the intensity of high-order and side of the zero-order diffraction peaks have been clapped under the twophoton absorption (TPA) polymerization threshold. In a word the polymerized volume can be chosen because the S l and the G u is correspondingly adjustable, even if the laser wavelength, objective lens and the photosensitive resin is fixed for a given two-photon microfabrication system. That means the radial superresolution of the two-photon microfabrication can be chosen.

  2. Three-phase photoconductive elements for directional free-space optical sensing

    NASA Astrophysics Data System (ADS)

    Jin, Xian; Guerrero, Daniel; Holzman, Jonathan F.

    2012-02-01

    An integrated photoconductive (PC) element is introduced as a new optoelectronic device in free-space optical (FSO) wireless applications. The device is a fundamental extension of the standard PC switch, as it has the capabilities for both local optoelectronic signal reception and active directional angle of arrival (AOA) sensing. This second capability is brought about through the use of a three-phase differential technique through three triangular PC switches arranged in a corner-cube architecture. Each PC switch is comprised of 50/150 nm Cr/Au electrodes, patterned on either side of a 200- micron GaAs PC gap, and is biased with the superposition of common DC and AC three-phase (120° phase-shifted) bias voltages. The DC bias forms a summed signal photocurrent on the central vertex output electrode and facilitates data reception; the AC three-phase bias facilitates link reliability for diversity reception in optical wireless communication systems. Complete theoretical and experimental angular characteristics of this device are presented in this work.

  3. Optimal design of multilayer diffractive optical elements with effective area method.

    PubMed

    Yang, Hongfang; Xue, Changxi; Li, Chuang; Wang, Ju

    2016-03-01

    The effective area method is described to design high-efficiency multiplayer diffractive optical elements (MLDOEs) with finite feature sizes for wide wave band. This method is presented with consideration of the shield effect between two elements of MLDOEs, and the optimal surface relief heights of MLDOEs are calculated with the effective area method. Then the comparisons of diffraction efficiency and polychromatic integral diffraction efficiency for MLDOEs with different period widths are described and simulated with the effective area method and scalar diffraction theory (SDT). Finally, the design results of MLDOEs obtained by SDT and the effective area method are compared by a rigorous electromagnetic analysis method, specifically, the finite-difference time-domain method. These results show that the limits of SDT for MLDOEs, ascertain and quantify the greatest sources of the diffraction efficiency loss due to the shield effect. The design results of the effective area method can obtain higher polychromatic integral diffraction efficiency than that of the SDT when the period width of MLDOEs is taken into account.

  4. Finite element simulation of extrusion of optical fiber preforms: Effects of wall slip

    NASA Astrophysics Data System (ADS)

    Zhang, Zhi Feng; Zhang, Yilei

    2016-03-01

    Extrusion has been successfully used to fabricate optical fiber preforms, especially microstructured ones. Although simplified mathematical model has been used to calculate the extrusion pressure or speed, more frequently die design and extrusion process optimization depend on trial and error, which is especially true for complex die and preform design. This paper employs the finite element method (FEM) to simulate the billet extrusion process to investigate the relationship between the extruding pressure, the billet viscosity, the wall slip condition and the extruding speed for extrusion of rod preforms. The slipping wall boundary condition is taken into account of the finite element model, and the simulated extruding pressure agrees with the one experimental value reported preciously. Then the dependence of the extruding speed on the extruding pressure, billet viscosity and the slip speed is systematically simulated. Simulated data is fitted to a second order polynomial model to describe their relationship, and the terms of the model are reduced from nine to five by using a statistical method while maintaining the fitting accuracy. The FEM simulation and the fitted model provide a convenient and dependable way to calculate the extrusion pressure, speed or other process parameters, which could be used to guide experimental design for future preform extrusion. Furthermore, the same simulation could be used to optimize die design and extrusion process to improve quality of extruded preforms.

  5. Three-dimensional shape measurement based on light patterns projection using diffractive optical elements

    NASA Astrophysics Data System (ADS)

    Twardowski, P.; Serio, B.; Raulot, V.; Guilhem, M.

    2010-05-01

    We propose a structured light micro-opto electromechanical system (MOEMS) projector specially designed to display successively a set of patterns in order to extract the 3-D shape of an object using a CCD cameras module and a small ARM-based computer for control, registration and numerical analysis. This method consists in a temporal codification using a modified Gray code combined with a classical phase shifting technique. Our approach is to combine the unambiguous and robust codification of the Gray code method with the high resolution of the phase shifting method to result in highly accurate 3D reconstructions. The proposed MOEMS is based on an array of vertical-cavity surface-emitting laser (VCSEL) combined with two planar static diffractive optical elements (DOEs) arrays. DOEs masters on quartz substrate have been fabricated using photolithography therefore replication in polycarbonate is possible at low cost. The first DOE array is designed to collimate the VCSEL light (Fresnel-type element) and the second one to project the codification patterns. DOEs have been designed and fabricated by surface etching to achieve a good diffraction efficiency using four phase levels. First we introduce the MEOMS principle and the features of the different components. We present the layout design of the DOEs and describe the issues related to the micro-fabrication process. An experimental study of the topography of the DOEs is presented and discussed. We then discuss fabrication aspects including the DOEs integration and packaging.

  6. Thermal aging of traditional and additively manufactured foams: analysis by time-temperature-superposition, constitutive, and finite-element models

    SciTech Connect

    Maiti, A.; Weisgraber, T. H.; Small, W.; Lewicki, J. P.; Duoss, E. B.; Spadaccini, C. M.; Pearson, M. A.; Chinn, S. C.; Wilson, T. S.; Maxwell, R. S.

    2016-12-08

    Cellular solids or foams are a very important class of materials with diverse applications ranging from thermal insulation and shock absorbing support cushions, to light-weight structural and floatation components, and constitute crucial components in a large number of industries including automotive, aerospace, electronics, marine, biomedical, packaging, and defense. In many of these applications the foam material is subjected to long periods of continuous stress, which can, over time, lead to a permanent change in structure and a degradation in performance. In this report we summarize our modeling efforts to date on polysiloxane foam materials that form an important component in our systems. Aging of the materials was characterized by two measured quantities, i.e., compression set and load retention. Results of accelerated aging experiments were analyzed by an automated time-temperaturesuperposition (TTS) approach, which creates a master curve that can be used for long-term predictions (over decades) under ambient conditions. When comparing such master curves for traditional (stochastic) foams with those for recently 3D-printed (i.e., additively manufactured, or AM) foams, it became clear that AM foams have superior aging behavior. To gain deeper understanding, we imaged the microstructure of both foams using X-ray computed tomography, and performed finite-element analysis of the mechanical response within these microstructures. This indicates a wider stress variation in the stochastic foam with points of more extreme local stress as compared to the 3D printed material.

  7. Holographically formed three-dimensional Penrose-type photonic quasicrystal through a lab-made single diffractive optical element.

    PubMed

    Harb, Ahmad; Torres, Faraon; Ohlinger, Kris; Lin, Yuankun; Lozano, Karen; Xu, Di; Chen, Kevin P

    2010-09-13

    Large-area three-dimensional Penrose-type photonic quasicrystals are fabricated through a holographic lithography method using a lab-made diffractive optical element and a single laser exposure. The diffractive optical element consists of five polymer gratings symmetrically orientated around a central opening. The fabricated Penrose-type photonic quasicrystal shows ten-fold rotational symmetry. The Laue diffraction pattern from the photonic quasi-crystal is observed to be similar to that of the traditional alloy quasi-crystal. A golden ratio of 1.618 is also observed for the radii of diffraction rings, which has not been observed before in artificial photonic quasicrystals.

  8. A Wafer-Bonded, Floating Element Shear-Stress Sensor Using a Geometric Moire Optical Transduction Technique

    NASA Technical Reports Server (NTRS)

    Horowitz, Stephen; Chen, Tai-An; Chandrasekaran, Venkataraman; Tedjojuwono, Ken; Cattafesta, Louis; Nishida, Toshikazu; Sheplak, Mark

    2004-01-01

    This paper presents a geometric Moir optical-based floating-element shear stress sensor for wind tunnel turbulence measurements. The sensor was fabricated using an aligned wafer-bond/thin-back process producing optical gratings on the backside of a floating element and on the top surface of the support wafer. Measured results indicate a static sensitivity of 0.26 microns/Pa, a resonant frequency of 1.7 kHz, and a noise floor of 6.2 mPa/(square root)Hz.

  9. 3D laser inspection of fuel assembly grid spacers for nuclear reactors based on diffractive optical elements

    NASA Astrophysics Data System (ADS)

    Finogenov, L. V.; Lemeshko, Yu A.; Zav'yalov, P. S.; Chugui, Yu V.

    2007-06-01

    Ensuring the safety and high operation reliability of nuclear reactors takes 100% inspection of geometrical parameters of fuel assemblies, which include the grid spacers performed as a cellular structure with fuel elements. The required grid spacer geometry of assembly in the transverse and longitudinal cross sections is extremely important for maintaining the necessary heat regime. A universal method for 3D grid spacer inspection using a diffractive optical element (DOE), which generates as the structural illumination a multiple-ring pattern on the inner surface of a grid spacer cell, is investigated. Using some DOEs one can inspect the nomenclature of all produced grids. A special objective has been developed for forming the inner surface cell image. The problems of diffractive elements synthesis, projecting optics calculation, adjusting methods as well as calibration of the experimental measuring system are considered. The algorithms for image processing for different constructive elements of grids (cell, channel hole, outer grid spacer rim) and the experimental results are presented.

  10. A New Method for Finding Optical Aberrations on the Basis of Analysis of the Object Hologram Without Additional Measurements

    NASA Astrophysics Data System (ADS)

    Matkivsky, V. A.; Moiseev, A. A.; Shilyagin, P. A.; Shabanov, D. V.; Gelikonov, G. V.; Gelikonov, V. M.

    2016-11-01

    We propose a new method of compensating for the wavefront aberrations during the image processing. The method employs the digital-holography potential. The developed algorithms allow one to find the wavefront distortions caused by the optical-path nonuniformities during the interference recording of images without additional measurements (i.e., without using the reference point source and measuring the wavefront distortions). The possibility of decreasing the wavefront aberrations from tens to several radians using digital methods is demonstrated.

  11. Pixel-Remapping Waveguide Addition to an Internally Sensed Optical Phased Array

    NASA Astrophysics Data System (ADS)

    Sibley, P.; Ward, R.; Roberts, L.; Francis, S.; Gross, S.; Shaddock, D.

    2016-09-01

    The optical phased array (OPA) system with internal phase sensing architecture being developed at the Australian National University has direct applications in tracking and manoeuvring of space debris from a ground-based continuous wave laser. The future effectiveness of this system is dependent on providing a high fill-factor for the emitter array as well as a collimated output in the far field. This is especially important when aiming for high power density incident on space debris and is currently governed by an unmodified single mode fiber to air interface at the final stage of the system. This research investigates the incorporation of a number of alternative optical head configurations, based on an output remapping waveguide. The waveguide will allow for control over the emitter separation, a key parameter in controlling the beam overlap and increasing the emitter fill factor. A remapping waveguide is designed for development with the 3D laser inscription process for a range of spatial configurations. Consideration is also given to a phase ambiguity issue with the feedback architecture and demonstration of the Gaussian Beam propagation simulations to which the experimental results will be compared is given.

  12. Non-additive interactions involving two distinct elements mediate sloppy-paired regulation by pair-rule transcription factors

    PubMed Central

    Prazak, Lisa; Fujioka, Miki; Gergen, J. Peter

    2010-01-01

    The relatively simple combinatorial rules responsible for establishing the initial metameric expression of sloppy-paired-1 (slp1) in the Drosophila blastoderm embryo make this system an attractive model for investigating the mechanism of regulation by pair rule transcription factors. This investigation of slp1 cis-regulatory architecture identifies two distinct elements, a proximal early stripe element (PESE) and a distal early stripe element (DESE) located from −3.1 kb to −2.5 kb and from −8.1 kb to −7.1 kb upstream of the slp1 promoter, respectively, that mediate this early regulation. The proximal element expresses only even-numbered stripes and mediates repression by Even-skipped (Eve) as well as by the combination of Runt and Fushi-tarazu (Ftz). A 272 basepair sub-element of PESE retains Eve-dependent repression, but is expressed throughout the even-numbered parasegments due to the loss of repression by Runt and Ftz. In contrast, the distal element expresses both odd and even-numbered stripes and also drives inappropriate expression in the anterior half of the odd-numbered parasegments due to an inability to respond to repression by Eve. Importantly, a composite reporter gene containing both early stripe elements recapitulates pair-rule gene-dependent regulation in a manner beyond what is expected from combining their individual patterns. These results indicate interactions involving distinct cis-elements contribute to the proper integration of pair-rule regulatory information. A model fully accounting for these results proposes that metameric slp1 expression is achieved through the Runt-dependent regulation of interactions between these two pair-rule response elements and the slp1 promoter. PMID:20435028

  13. Finite-element analysis of the optical-texture-mediated photoresponse in a nematic strip

    NASA Astrophysics Data System (ADS)

    Chung, Hayoung; Yun, Jung-Hoon; Choi, Joonmyung; Cho, Maenghyo

    2016-10-01

    In a nematic solid, wherein liquid crystal molecules are incorporated into polymeric chains, the chromophore phase is projected onto the polymer conformation, changing the stress-free configuration metric. Stimulated actuation cannot be separated from the structure itself, since the mesoscopic polymer properties dictate the degree and type of shape change. In this research, we focused on self-deforming device programming, inspired by recent optical techniques, to pattern nontrivial alignment textures and induce exotic strain fields on specimens. A finite-element framework incorporating a light-thermo-order coupled constitutive relation and geometric nonlinearities was utilized to compute mechanical deformations for given external stimuli. The distortion of planar strips into various exotic 3D shapes was simulated, and disclination-defect-like liquid crystal texture topographies with different defect strengths produced various many-poled shapes upon irradiation, as observed experimentally. The effects of the boundary conditions and geometric nonlinearities were also examined, exemplifying the need for a comprehensive finite-element-based framework. The same method was applied to textures naturally emerging due to static distortion, and the effects of the prescribed inhomogeneities on the overall deformations, which is the basis of inverse design, were observed. Furthermore, we analyzed the local Poisson-effect-induced instability resulting from inscribing a hedgehog disclination texture onto a solid; the onset of buckling-like deformations was observed energetically, and the relations between this onset and other physical properties were elucidated to enable microstate design while maintaining structural stability. These results will facilitate the development and comprehension of the mechanisms of remotely light-controlled self-assembly and propulsion systems that may soon be realized.

  14. Finite-element analysis of the optical-texture-mediated photoresponse in a nematic strip

    NASA Astrophysics Data System (ADS)

    Chung, Hayoung; Yun, Jung-Hoon; Choi, Joonmyung; Cho, Maenghyo

    2017-01-01

    In a nematic solid, wherein liquid crystal molecules are incorporated into polymeric chains, the chromophore phase is projected onto the polymer conformation, changing the stress-free configuration metric. Stimulated actuation cannot be separated from the structure itself, since the mesoscopic polymer properties dictate the degree and type of shape change. In this research, we focused on self-deforming device programming, inspired by recent optical techniques, to pattern nontrivial alignment textures and induce exotic strain fields on specimens. A finite-element framework incorporating a light-thermo-order coupled constitutive relation and geometric nonlinearities was utilized to compute mechanical deformations for given external stimuli. The distortion of planar strips into various exotic 3D shapes was simulated, and disclination-defect-like liquid crystal texture topographies with different defect strengths produced various many-poled shapes upon irradiation, as observed experimentally. The effects of the boundary conditions and geometric nonlinearities were also examined, exemplifying the need for a comprehensive finite-element-based framework. The same method was applied to textures naturally emerging due to static distortion, and the effects of the prescribed inhomogeneities on the overall deformations, which is the basis of inverse design, were observed. Furthermore, we analyzed the local Poisson-effect-induced instability resulting from inscribing a hedgehog disclination texture onto a solid; the onset of buckling-like deformations was observed energetically, and the relations between this onset and other physical properties were elucidated to enable microstate design while maintaining structural stability. These results will facilitate the development and comprehension of the mechanisms of remotely light-controlled self-assembly and propulsion systems that may soon be realized.

  15. Data veracity checks for the alignment of the JWST optical telescope element

    NASA Astrophysics Data System (ADS)

    Levi, Josh; Glassman, Tiffany; Farey, Mike; Liepmann, Till

    2016-09-01

    Alignment of the James Webb Space Telescope (JWST) Optical Telescope Element (OTE) requires a multitude of demanding and exacting dimensional and positional measurements. Many of the alignment requirements are in the range of hundreds of microns over significant distances (up to 8 m) on a flexible structure, which creates stringent accuracy demands on the alignment measurements. Furthermore, to optimize the performance of the system, the telescope is aligned to a relatively small (<1 m) structure in the center, creating the potential for coordinate system errors. Measurements have been performed using laser trackers (predominantly), photogrammetry, coordinate measurement machine (CMM), and laser radar instruments. Measurements from different instruments/ stations are combined and processed within SpatialAnalyzer (SA) commercial software using the Unified Spatial Metrology Network (USMN) feature. While this approach should yield the best possible accuracies (hopefully in the tens of microns range), our experience has been that there can be significant errors in the data based on the details of how SA is set up and how the measurements are conducted. As a result of our experience, we have developed analytical tools and processes that allow us to test the data veracity in near real time using, for example, Excel spreadsheet calculations. These tools combine measurements made at various levels of assembly, measurements of cross check points, and finite element analysis to determine the correlated and uncorrelated discrepancies in the measured data. This provides a detailed understanding of systematic and random measurement errors and has allowed us to quickly uncover issues with placement, measurement, and modeling, as well as to quantify our measurement performance.

  16. A soft x-ray beamline capable of canceling the performance impairment due to power absorbed on its optical elements.

    PubMed

    Reininger, Ruben; Kriesel, Ken; Hulbert, S L; Sánchez-Hanke, Cecilia; Arena, D A

    2008-03-01

    We present an entrance slitless beamline design capable of maintaining its very high performance in terms of energy resolution (>10(4)) and spot size (4x4 microm2) at the sample position despite being exposed to more than 2.15 kW of undulator radiation and a maximum power density on the optics of more than 0.9 W/mm2. Ray tracing simulations of this beamline under the worst-case thermal deformations of the optical element surfaces verify that appropriate focusing corrections are able to cancel the deleterious effects of these deformations. One of the necessary conditions for this cancellation is to illuminate the optical elements with a larger solid angle than the undulator's central cone, which contains the usable photons but is considerably smaller than the angular power distribution.

  17. Recent advances in the application of computer-controlled optical finishing to produce very high-quality transmissive optical elements and windows

    NASA Astrophysics Data System (ADS)

    Askinazi, Joel; Estrin, Aleksandr; Green, Alan; Turner, Aaron N.

    2003-09-01

    Large aperture (20-inch diameter) sapphire optical windows have been identified as a key element of new and/or upgraded airborne electro-optical systems. These windows typically require a transmitted wave front error of much less than 0.1 waves rms @ 0.63 microns over 7 inch diameter sub-apertures. Large aperture (14-inch diameter by 4-inch thick) sapphire substrates have also been identified as a key optical element of the Laser Interferometer Gravitational Wave Observatory (LIGO). This project is under joint development by the California Institute of Technology (Caltech) and the Massachusetts Institute of Technology under cooperative agreement with the National Science foundation (NSF). These substrates are required to have a transmitted wave front error of 20 nm (0.032 waves) rms @ 0.63 microns over 6-inch sub-apertures with a desired error of 10 nm (0.016 waves) rms. Owing to the spatial variations in the optical index of refraction potentially anticipated within 20-inch diameter sapphire, thin (0.25 - 0.5-inch) window substrates, as well as within the 14-inch diameter by 4-inch thick substrates for the LIGO application, our experience tells us that the required transmitted wave front errors can not be achieved with standard optical finishing techniques as they can not readily compensate for errors introduced by inherent material characteristics. Computer controlled optical finishing has been identified as a key technology likely required to enable achievement of the required transmitted wave front errors. Goodrich has developed this technology and has previously applied it to finish high quality sapphire optical windows with a range of aperture sizes from 4-inch to 13-inch to achieve transmitted wavefront errors comparable to these new requirements. This paper addresses successful recent developments and accomplishments in the application of this optical finishing technology to sequentially larger aperture and thicker sapphire windows to achieve the

  18. Imprinting high-gradient topographical structures onto optical surfaces using magnetorheological finishing: Manufacturing corrective optical elements for high-power laser applications

    DOE PAGES

    Menapace, Joseph A.; Ehrmann, Paul E.; Bayramian, Andrew J.; ...

    2016-03-15

    Corrective optical elements form an important part of high-precision optical systems. We have developed a method to manufacture high-gradient corrective optical elements for high-power laser systems using deterministic magnetorheological finishing (MRF) imprinting technology. Several process factors need to be considered for polishing ultraprecise topographical structures onto optical surfaces using MRF. They include proper selection of MRF removal function and wheel sizes, detailed MRF tool and interferometry alignment, and optimized MRF polishing schedules. Dependable interferometry also is a key factor in high-gradient component manufacture. A wavefront attenuating cell, which enables reliable measurement of gradients beyond what is attainable using conventional interferometry,more » is discussed. The results of MRF imprinting a 23 μm deep structure containing gradients over 1.6 μm / mm onto a fused-silica window are presented as an example of the technique’s capabilities. As a result, this high-gradient element serves as a thermal correction plate in the high-repetition-rate advanced petawatt laser system currently being built at Lawrence Livermore National Laboratory.« less

  19. Imprinting high-gradient topographical structures onto optical surfaces using magnetorheological finishing: Manufacturing corrective optical elements for high-power laser applications

    SciTech Connect

    Menapace, Joseph A.; Ehrmann, Paul E.; Bayramian, Andrew J.; Bullington, Amber; Di Nicola, Jean -Michel G.; Haefner, Constantin; Jarboe, Jeffrey; Marshall, Christopher; Schaffers, Kathleen I.; Smith, Cal

    2016-03-15

    Corrective optical elements form an important part of high-precision optical systems. We have developed a method to manufacture high-gradient corrective optical elements for high-power laser systems using deterministic magnetorheological finishing (MRF) imprinting technology. Several process factors need to be considered for polishing ultraprecise topographical structures onto optical surfaces using MRF. They include proper selection of MRF removal function and wheel sizes, detailed MRF tool and interferometry alignment, and optimized MRF polishing schedules. Dependable interferometry also is a key factor in high-gradient component manufacture. A wavefront attenuating cell, which enables reliable measurement of gradients beyond what is attainable using conventional interferometry, is discussed. The results of MRF imprinting a 23 μm deep structure containing gradients over 1.6 μm / mm onto a fused-silica window are presented as an example of the technique’s capabilities. As a result, this high-gradient element serves as a thermal correction plate in the high-repetition-rate advanced petawatt laser system currently being built at Lawrence Livermore National Laboratory.

  20. Effect of CaF{sub 2} addition on optical properties of barium phosphate glasses

    SciTech Connect

    Kumar, N. Manoj Rao, G. Venkateswara Akhila, B. E. Shashikala, H. D.

    2014-04-24

    Ternary barium phosphate glasses, (50−X)BaO−XCaF{sub 2}−50P{sub 2}O{sub 5} have been prepared by adding 0-10 mol% of CaF{sub 2} to binary barium phosphate glasses. The amorphous nature of the prepared glasses was confirmed by X-ray diffraction technique. The UV-Visible absorption spectra have been recorded, optical band gap energy Eopt and Urbach energy Etail were determined. Shift in Eopt and Etail with increase in concentration of CaF{sub 2} is noted. FTIR analysis was carried out to investigate the short and intermediate-range orders in glasses. Shift of (P-O-P) band to higher wave number with the substitution of BaO with CaF{sub 2} shows the shortening of the phosphate chains. Hardness and density of glass samples were measured and correlated with the composition of glasses.

  1. Effect of the addition of low rare earth elements (lanthanum, neodymium, cerium) on the biodegradation and biocompatibility of magnesium.

    PubMed

    Willbold, Elmar; Gu, Xuenan; Albert, Devon; Kalla, Katharina; Bobe, Katharina; Brauneis, Maria; Janning, Carla; Nellesen, Jens; Czayka, Wolfgang; Tillmann, Wolfgang; Zheng, Yufeng; Witte, Frank

    2015-01-01

    Rare earth elements are promising alloying element candidates for magnesium alloys used as biodegradable devices in biomedical applications. Rare earth elements have significant effects on the high temperature strength as well as the creep resistance of alloys and they improve magnesium corrosion resistance. We focused on lanthanum, neodymium and cerium to produce magnesium alloys with commonly used rare earth element concentrations. We showed that low concentrations of rare earth elements do not promote bone growth inside a 750 μm broad area around the implant. However, increased bone growth was observed at a greater distance from the degrading alloys. Clinically and histologically, the alloys and their corrosion products caused no systematic or local cytotoxicological effects. Using microtomography and in vitro experiments, we could show that the magnesium-rare earth element alloys showed low corrosion rates, both in in vitro and in vivo. The lanthanum- and cerium-containing alloys degraded at comparable rates, whereas the neodymium-containing alloy showed the lowest corrosion rates.

  2. Laser-assisted manufacturing of micro-optical volume elements for enhancing the amount of light absorbed by solar cells in photovoltaic modules

    NASA Astrophysics Data System (ADS)

    Peharz, Gerhard; Kuna, Ladislav; Leiner, Claude

    2015-03-01

    The laser-generation of micro-optical volume elements is a promising approach to decrease the optical shadowing of front side metal contacts of solar cells. Focusing a femtosecond laser beam into the volume of the encapsulation material causes a local modification its optical constants. Suchlike fabricated micro-optical elements can be used to decrease the optical shadowing of the front side metallization of c-Si solar cells. Test samples comprising of a sandwich structure of a glass sheet with metallic grid-lines, an Ethylene-vinyl acetate (EVA) encapsulant and another glass sheet were manufactured in order to investigate the optical performance of the volume optics. Transmission measurements show that the shadowing of the metalling grid-lines is substantially decreased by the micro-optical volume elements created in the EVA bulk right above the grid-fingers. A detailed investigation of the optical properties of these volume elements was performed: (i) experimentally on the basis of goniometric measurements, as well as (ii) theoretically by applying optical modelling and optimization procedures. This resulted in a better understanding of the effectiveness of the optical volume elements in decreasing the optical shadowing of metal grid lines on the active cell surfaces. Moreover, results of photovoltaic mini-modules with incorporated micro-optical volume elements are presented. Results of optical simulation and Laser Beam Induced Current (LBIC) experiments show that the losses due to the grid fingers can be reduced by about 50%, when using this fs-laser structuring approach for the fabrication of micro-optical volume elements in the EVA material.

  3. Finite element analysis of a variable optical attenuator based on s-shape polymer waveguide

    NASA Astrophysics Data System (ADS)

    Wan, Jing; Wu, Lingxun; Xue, Fenglan; Hu, Jian; Fu, Yanjun; Zhang, Wei; Hu, Fangren

    2016-01-01

    A variable optical attenuator (VOA) based on S-shape polymer waveguide is demonstrated at the wavelength λ = 1.55 micron. The VOA consists of straight input and output waveguides, an S-shape waveguide and a pair of deposited electrodes. The cladding material of S waveguide is Poly (methyl methacrylate/disperse red 1) (PMMA/DR1) and the core material of S waveguide is SiON. The refractive index of the polymer cladding at S waveguide is modified by the applied electric voltage. Light scatters at the S waveguide and the VOA has large energy loss in the original state at voltage-off. In the voltage-on state, the refractive index of the polymer of the S waveguide reduces, and energy loss changes as the voltage increases. The attenuation of the VOA can be controled and adjusted by the applied voltage. The beam propagation method(BPM) and finite element analysis are employed to simulate and analyse the VOA. The results show that the VOA has large variable attenuation range of 45.2dB and low insertion loss of 0.8dB.

  4. Mechanical blind gap measurement tool for alignment of the JWST Optical Telescope Element

    NASA Astrophysics Data System (ADS)

    Liepmann, Till

    2016-09-01

    This paper describes a novel gap gauge tool that is used to provide an independent check of the James Webb Space Telescope (JWST) Optical Telescope Element (OTE) primary mirror alignment. Making accurate measurements of the mechanical gaps between the OTE mirror segments is needed to verify that the segments were properly aligned relative to each other throughout the integration and test of the 6.6 meter telescope. The gap between the Primary Mirror Segment Assemblies (PMSA) is a sensitive indicator of the relative clocking and decenter. Further, the gap measurements are completely independent of all the other measurements use in the alignment process (e.g. laser trackers and laser radar). The gap measurement is a challenge, however, that required a new approach. Commercial gap measurements tools were investigated; however no suitable solution is available. The challenge of this measurement is due to the required 0.1 mm accuracy, the close spacing of the mirrors segments (approximately 3-9mm), the acute angle between the segment sides (approximately 4 degrees), and the difficult access to the blind gap. Several techniques were considered and tested before selecting the gauge presented here. This paper presents the theory, construction and calibration of the JWST gap gauge that is being used to measure and verify alignment of the OTE primary mirror segments.

  5. Using binary optical elements (BOEs) to generate rectangular spots for illumination in micro flow cytometer

    PubMed Central

    Zhao, Jingjing; You, Zheng

    2016-01-01

    This work introduces three rectangular quasi-flat-top spots, which are provided by binary optical elements (BOEs) and utilized for the illumination in a microflow cytometer. The three spots contain, respectively, one, two, and three rectangles (R1, R2, and R3). To test the performance of this mechanism, a microflow cytometer is established by integrating the BOEs and a three-dimensional hydrodynamic focusing chip. Through the experiments of detecting fluorescence microbeads, the three spots present good fluorescence coefficients of variation in comparison with those derived from commercial instruments. Benefiting from a high spatial resolution, when using R1 spot, the micro flow cytometer can perform a throughput as high as 20 000 events per second (eps). Illuminated by R2 or R3 spot, one bead emits fluorescence twice or thrice, thus the velocity can be measured in real time. Besides, the R3 spot provides a long-time exposure, which is conducive to improving fluorescence intensity and the measurement stability. In brief, using the spots shaped and homogenized by BOEs for illumination can increase the performance and the functionality of a micro flow cytometer. PMID:27733892

  6. Fabrication error analysis for diffractive optical elements used in a lithography illumination system

    NASA Astrophysics Data System (ADS)

    Wang, Jian; Zhang, Fang; Song, Qiang; Zeng, Aijun; Zhu, Jing; Huang, Huijie

    2015-04-01

    With the constant shrinking of printable critical dimensions in photolithography, off-axis illumination (OAI) becomes one of the effective resolution-enhancement methods facing these challenges. This, in turn, is driving much more strict requirements, such as higher diffractive efficiency of the diffractive optical elements (DOEs) used in the OAI system. Since the design algorithms to optimize DOEs' phase profile are improved, the fabrication process becomes the main limiting factor leading to energy loss. Tolerance analysis is the general method to evaluate the fabrication accuracy requirement, which is especially useful for highly specialized deep UV applications with small structures and tight tolerances. A subpixel DOE simulation model is applied for tolerance analysis of DOEs by converting the abstractive fabrication structure errors into quantifiable subpixel phase matrices. Adopting the proposed model, four kinds of fabrication errors including misetch, misalignment, feature size error, and feature rounding error are able to be investigated. In the simulation experiments, systematic fabrication error studies of five typical DOEs used in 90-nm scanning photolithography illumination system are carried out. These results are valuable in the range of high precision DOE design algorithm and fabrication process optimization.

  7. Injection-seeded optical parametric oscillator and system

    SciTech Connect

    Lucht, Robert P.; Kulatilaka, Waruna D.; Anderson, Thomas N.; Bougher, Thomas L.

    2007-10-09

    Optical parametric oscillators (OPO) and systems are provided. The OPO has a non-linear optical material located between two optical elements where the product of the reflection coefficients of the optical elements are higher at the output wavelength than at either the pump or idler wavelength. The OPO output may be amplified using an additional optical parametric amplifier (OPA) stage.

  8. Performance of an optical encoder based on a nondiffractive beam implemented with a specific photodetection integrated circuit and a diffractive optical element.

    PubMed

    Quintián, Fernando Perez; Calarco, Nicolás; Lutenberg, Ariel; Lipovetzky, José

    2015-09-01

    In this paper, we study the incremental signal produced by an optical encoder based on a nondiffractive beam (NDB). The NDB is generated by means of a diffractive optical element (DOE). The detection system is composed by an application specific integrated circuit (ASIC) sensor. The sensor consists of an array of eight concentric annular photodiodes, each one provided with a programmable gain amplifier. In this way, the system is able to synthesize a nonuniform detectivity. The contrast, amplitude, and harmonic content of the sinusoidal output signal are analyzed. The influence of the cross talk among the annular photodiodes is placed in evidence through the dependence of the signal contrast on the wavelength.

  9. The cyclic oxidation resistance at 1200 C of beta-NiAl, FeAl, and CoAl alloys with selected third element additions

    NASA Technical Reports Server (NTRS)

    Barrett, C. A.; Titran, R. H.

    1992-01-01

    The intermetallic compounds Beta-NiAl, FeAl, and CoAl were tested in cyclic oxidation with selected third element alloy additions. Tests in static air for 200 1-hr cycles at 1200 C indicated by specific weight change/time data and x-ray diffraction analysis that the 5 at percent alloy additions did not significantly improve the oxidation resistance over the alumina forming baseline alloys without the additions. Many of the alloy additions were actually deleterious. Ta and Nb were the only alloy additions that actually altered the nature of the oxide(s) formed and still maintained the oxidation resistance of the protective alumina scale.

  10. Photographic Atlas and Three-Dimensional Reconstruction of the Holotype Skull of Euhelopus zdanskyi with Description of Additional Cranial Elements

    PubMed Central

    Poropat, Stephen F.; Kear, Benjamin P.

    2013-01-01

    Background Euhelopus zdanskyi is one of relatively few sauropod taxa known from an almost complete skull and mandible. Recent phylogenetic analyses suggest that Euhelopus is a somphospondylan titanosauriform, and that it is a member of the clade (Euhelopodidae) which is the sister taxon to the hugely successful, dominantly Cretaceous sauropod group Titanosauria. Methodology/Principal Findings The skull elements of Euhelopus were CT scanned at Uppsala Akademiska Sjukhuset. Three-dimensional models of the elements were constructed from the DICOM data using Mimics 14.0, InVesalius 3.0, and GeoMagic Studio 2012, the skull was rearticulated in Rhinoceros 4.0, and the final version was rendered in GeoMagic Studio 2012. Conclusions/Significance The fact that relatively complete sauropod skulls are so rare in the fossil record, particularly among titanosauriforms, means that the skulls that are known should be as thoroughly described and well-illustrated as possible. This contribution supplements previous descriptions of the cranial elements of Euhelopus, one of the few euhelopodid taxa for which cranial material is known, by presenting a comprehensive photographic atlas of the skull elements to facilitate a better understanding of their morphology. We describe several elements which have been overlooked in past studies of Euhelopus, and also provide as accurate a reconstruction of the skull as possible (in the absence of the braincase), the most significant components of which are the articulations of the palate and the mandible. PMID:24278222

  11. PARAMETRIC STUDY OF TISSUE OPTICAL CLEARING BY LOCALIZED MECHANICAL COMPRESSION USING COMBINED FINITE ELEMENT AND MONTE CARLO SIMULATION.

    PubMed

    Vogt, William C; Shen, Haiou; Wang, Ge; Rylander, Christopher G

    2010-07-01

    Tissue Optical Clearing Devices (TOCDs) have been shown to increase light transmission through mechanically compressed regions of naturally turbid biological tissues. We hypothesize that zones of high compressive strain induced by TOCD pins produce localized water displacement and reversible changes in tissue optical properties. In this paper, we demonstrate a novel combined mechanical finite element model and optical Monte Carlo model which simulates TOCD pin compression of an ex vivo porcine skin sample and modified spatial photon fluence distributions within the tissue. Results of this simulation qualitatively suggest that light transmission through the skin can be significantly affected by changes in compressed tissue geometry as well as concurrent changes in tissue optical properties. The development of a comprehensive multi-domain model of TOCD application to tissues such as skin could ultimately be used as a framework for optimizing future design of TOCDs.

  12. Seedless synthesis of nanocomposites, optical properties, and effects of additives on their surface resonance plasmon bands.

    PubMed

    Zaheer, Zoya; Aazam, Elham Shafik

    2017-04-03

    The work describes an easy seedless competitive chemical reduction method for the synthesis of Ag@Au/Ag bimetallic nanoparticles by mixing AgNO3, HAuCl4 and cysteine. Transmission electron microscope (TEM) images show that the large number of irregular, cross-linking, and aggregated Ag@Au/Ag are formed in a reaction mixture (HAuCl4+AgNO3+cysteine), whereas flower-like nanocomposites are obtained in presence of cetyltrimethylammonium bromide (CTAB), which acted as a shape-directing agent. Optical images reveal that the initially reaction proceeds through formation of purple color, which changes into dark brown color with the reaction time, indicating the formation of Ag@Au/Ag nanocomposites. The Ag(+) has strong tendency to form complex with cysteine. Firstly, the reduction of Ag(+) ions to Ag(0) occurred by the HS group of the cysteine-Ag complex. Secondly, AuCl4(-) ions adsorbed on the positive surface of Ag(0), which undergoes reduction by potential deposition, and leads to the formation of Ag@Au/Ag bimetallic nanoparticles. Inorganic electrolytes (NaCl, NaBr, NaNO3 and Na2SO4) have significant impact on the stability and aggregation of Ag@Au/Ag nanocomposites.

  13. The sequential addition and migration method to generate representative volume elements for the homogenization of short fiber reinforced plastics

    NASA Astrophysics Data System (ADS)

    Schneider, Matti

    2017-02-01

    We present an algorithm for generating volume elements of short fiber reinforced plastic microstructures for prescribed fourth order fiber orientation tensor, fiber aspect ratio and solid volume fraction. The algorithm inserts fibers randomly into an existing microstructure, and removes the resulting overlap systematically based on a gradient descent method. In contrast to existing methods, large fiber aspect ratios (up to 150) and large volume fractions (60 vol% for isotropic orientation and aspect ratio of 33) can be reached. We study the effective linear elastic properties of the resulting microstructures, depending on fiber orientation, volume fraction as well as aspect ratio, and examine the size of a corresponding representative volume element.

  14. Characterization of embedded fiber optic strain sensors into metallic structures via ultrasonic additive manufacturing

    NASA Astrophysics Data System (ADS)

    Schomer, John J.; Hehr, Adam J.; Dapino, Marcelo J.

    2016-04-01

    Fiber Bragg Grating (FBG) sensors measure deviation in a reflected wavelength of light to detect in-situ strain. These sensors are immune to electromagnetic interference, and the inclusion of multiple FBGs on the same fiber allows for a seamlessly integrated sensing network. FBGs are attractive for embedded sensing in aerospace applications due to their small noninvasive size and prospect of constant, real-time nondestructive evaluation. In this study, FBG sensors are embedded in aluminum 6061 via ultrasonic additive manufacturing (UAM), a rapid prototyping process that uses high power ultrasonic vibrations to weld similar and dissimilar metal foils together. UAM was chosen due to the desire to embed FBG sensors at low temperatures, a requirement that excludes other additive processes such as selective laser sintering or fusion deposition modeling. In this paper, the embedded FBGs are characterized in terms of birefringence losses, post embedding strain shifts, consolidation quality, and strain sensing performance. Sensors embedded into an ASTM test piece are compared against an exterior surface mounted foil strain gage at both room and elevated temperatures using cyclic tensile tests.

  15. Compact optical true time delay beamformer for a 2D phased array antenna using tunable dispersive elements.

    PubMed

    Ye, Xingwei; Zhang, Fangzheng; Pan, Shilong

    2016-09-01

    A hardware-compressive optical true time delay architecture for 2D beam steering in a planar phased array antenna is proposed using fiber-Bragg-grating-based tunable dispersive elements (TDEs). For an M×N array, the proposed system utilizes N TDEs and M wavelength-fixed optical carriers to control the time delays. Both azimuth and elevation beam steering are realized by programming the settings of the TDEs. An experiment is carried out to demonstrate the delay controlling in a 2×2 array, which is fed by a wideband pulsed signal. Radiation patterns calculated from the experimentally measured waveforms at the four antennas match well with the theoretical results.

  16. Thermal strain along optical fiber in lightweight composite FOG : Brillouin-based distributed measurement and finite element analysis

    NASA Astrophysics Data System (ADS)

    Minakuchi, Shu; Sanada, Teruhisa; Takeda, Nobuo; Mitani, Shinji; Mizutani, Tadahito; Sasaki, Yoshinobu; Shinozaki, Keisuke

    2014-05-01

    Thermal strain significantly affects stability of fiber optic gyroscope (FOG) performance. This study investigates thermal strain development in a lightweight carbon fiber reinforced plastic (CFRP) FOG under thermal vacuum condition simulating space environment. First, we measure thermal strain distribution along an optical fiber in a CFRP FOG using a Brillouin-based high-spatial resolution system. The key strain profile is clarified and the strain development is simulated using finite element analysis. Finally, several constituent materials for FOG are quantitatively compared from the aspect of the maximum thermal strain and the density, confirming the clear advantage of CFRP.

  17. Enhanced Optical Properties of Cu-In-S Quantum Dots with Zn Addition

    NASA Astrophysics Data System (ADS)

    Chi, Tran Thi Kim; Thuy, Ung Thi Dieu; Huyen, Tran Thi Thuong; Thuy, Nguyen Thi Minh; Le, Nguyen Thi; Liem, Nguyen Quang

    2016-05-01

    Quaternary Cu-In-Zn-S (CIZS) alloy quantum dots (QDs) have been chemically synthesized by a hydrothermal method at 120°C and heating-up method using diesel as a high-boiling-point reaction solvent at 220°C. The resulting CuInS2 (CIS) QDs with small Zn addition of 10% into the precursors possessed tetragonal structure, spherical morphology, and small size of 3 nm, as characterized by x-ray diffraction (XRD) analysis, Raman spectroscopy, and high-resolution transmission electron microscopy (HR-TEM). The absorption (Abs) and photoluminescence (PL) spectra of the CIZS alloy QDs both shifted to shorter wavelength (higher energy) in comparison with CIS QDs. The absorption edge and PL peak of the CIZS alloy QDs shifted to shorter wavelength, and the corresponding intensity increased with decreasing temperature in the range of 15 K to 300 K.

  18. Optical properties, morphology and elemental composition of atmospheric particles at T1 supersite on MILAGRO campaign

    NASA Astrophysics Data System (ADS)

    Carabali, G.; Mamani-Paco, R.; Castro, T.; Peralta, O.; Herrera, E.; Trujillo, B.

    2012-03-01

    Atmospheric particles were sampled at T1 supersite during MILAGRO campaign, in March 2006. T1 was located at the north of Mexico City (MC). Aerosol sampling was done by placing copper grids for Transmission Electron Microscope (TEM) on the last five of an 8-stage MOUDI cascade impactor. Samples were obtained at different periods to observe possible variations on morphology. Absorption and scattering coefficients, as well as particle concentrations (0.01-3 μm aerodynamic diameter) were measured simultaneously using a PSAP absorption photometer, a portable integrating nephelometer, and a CPC particle counter. Particle images were acquired at different magnifications using a CM 200 Phillips TEM-EDAX system, and then calculated the border-based fractal dimension. Also, Energy Dispersive X-Ray Spectroscopy (EDS) was used to determine the elemental composition of particles. The morphology of atmospheric particles for two aerodynamic diameters (0.18 and 1.8 μm) was compared using border-based fractal dimension to relate it to the other particle properties, because T1-generated particles have optical, morphological and chemical properties different from those transported by the MC plume. Particles sampled under MC pollution influence showed not much variability, suggesting that more spherical particles (border-based fractal dimension close to 1.0) are more common in larger sizes (d50 = 1.8 μm), which may be attributed to aerosol aging and secondary aerosol formation. Between 06:00 and 09:00 a.m., smaller particles (d50 = 0.18 μm) had more irregular shapes resulting in higher border-based fractal dimensions (1.2-1.3) for samples with more local influence. EDS analysis in d50 = 0.18 μm particles showed high contents of carbonaceous material, Si, Fe, K, and Co. Perhaps, this indicates an impact from industrial and vehicle emissions on atmospheric particles at T1.

  19. Inductively Coupled Plasma Optical Emission Spectrometry for Rare Earth Elements Analysis

    NASA Astrophysics Data System (ADS)

    He, Man; Hu, Bin; Chen, Beibei; Jiang, Zucheng

    2017-01-01

    Inductively coupled plasma optical emission spectrometry (ICP-OES) merits multielements capability, high sensitivity, good reproducibility, low matrix effect and wide dynamic linear range for rare earth elements (REEs) analysis. But the spectral interference in trace REEs analysis by ICP-OES is a serious problem due to the complicated emission spectra of REEs, which demands some correction technology including interference factor method, derivative spectrum, Kalman filtering algorithm and partial least-squares (PLS) method. Matrix-matching calibration, internal standard, correction factor and sample dilution are usually employed to overcome or decrease the matrix effect. Coupled with various sample introduction techniques, the analytical performance of ICP-OES for REEs analysis would be improved. Compared with conventional pneumatic nebulization (PN), acid effect and matrix effect are decreased to some extent in flow injection ICP-OES, with higher tolerable matrix concentration and better reproducibility. By using electrothermal vaporization as sample introduction system, direct analysis of solid samples by ICP-OES is achieved and the vaporization behavior of refractory REEs with high boiling point, which can easily form involatile carbides in the graphite tube, could be improved by using chemical modifier, such as polytetrafluoroethylene and 1-phenyl-3-methyl-4-benzoyl-5-pyrazone. Laser ablation-ICP-OES is suitable for the analysis of both conductive and nonconductive solid samples, with the absolute detection limit of ng-pg level and extremely low sample consumption (0.2 % of that in conventional PN introduction). ICP-OES has been extensively employed for trace REEs analysis in high-purity materials, and environmental and biological samples.

  20. Determination of trace elements in biodiesel and vegetable oil by inductively coupled plasma optical emission spectrometry following alcohol dilution

    NASA Astrophysics Data System (ADS)

    Chaves, Eduardo S.; de Loos-Vollebregt, Margaretha T. C.; Curtius, Adilson J.; Vanhaecke, Frank

    2011-09-01

    A method for the simultaneous determination of Ca, Cu, Fe, K, Mg, Na, P, S and Zn in biodiesels and vegetable oils by inductively coupled plasma optical emission spectrometry (ICP-OES) has been developed. The method - based on the use of an ICP-OES instrument outfitted with a spectrometer in Paschen-Runge mount, equipped with linear charge coupled device detectors monitoring the entire spectrum from 130 to 770 nm - offers a high sample throughput as sample preparation is limited to dilution with alcohol, while all elements of interest are determined simultaneously. Ethanol is only suitable in the context of biodiesel analysis, whereas dilution with 1-propanol also allows application of the method, without any additional modification, to analysis of vegetable oils. As a result, the dilution with 1-propanol is preferable. Sample introduction was carried out with pneumatic nebulization and spectral interferences from carbon-containing compounds were reduced by cooling the cyclonic spray chamber to - 5 °C. The remaining spectral interferences in the low-UV region were efficiently corrected for by the background correction system offered in the software of the ICP-OES instrument used. Calibration was carried out against inorganic standards diluted in ethanol or 1-propanol, while Y was used as an internal standard, correcting for non-spectral interference and sensitivity drift. The accuracy of the method was verified through the analysis of the NIST SRMs 2772 and 2773 biodiesel reference materials. Additionally, as for most of the target elements only indicative concentration values are available for these reference materials, recovery tests have been performed using inorganic and organic standards. The results obtained were in good agreement with the values found on the certificate for both ethanol and 1-propanol sample dilution, while the recoveries were between 87 and 116% for biodiesel and between 95 and 106% for vegetable oils. The measurement precision expressed

  1. All-optical digital logic: Full addition or subtraction on a three-state system

    SciTech Connect

    Remacle, F.; Levine, R. D.

    2006-03-15

    Stimulated Raman adiabatic passage (STIRAP) is a well-studied pump-probe control scheme for manipulating the population of quantum states of atoms or molecules. By encoding the digits to be operated on as 'on' or 'off' laser input signals we show how STIRAP can be used to implement a finite-state logic machine. The physical conditions required for an effective STIRAP operation are related to the physical conditions expected for a logic machine. In particular, a condition is derived on the mean number of photons that represent an on pulse. A finite-state machine computes Boolean expressions that depend both on the input and on the present state of the machine. With two input signals we show how to implement a full adder where the carry-in digit is stored in the state of the machine. Furthermore, we show that it is possible to store the carry-out digit as the next state and thereby return the machine to a state ready for the next full addition. Such a machine operates as a cyclical full adder. We further show how this full adder can equally well be operated as a full subtractor. To the best of our knowledge this is the first example of a nanosized system that implements a full subtraction.

  2. Molecular Imprinting of Silica Nanoparticle Surfaces via Reversible Addition-Fragmentation Polymerization for Optical Biosensing Applications

    NASA Astrophysics Data System (ADS)

    Oluz, Zehra; Nayab, Sana; Kursun, Talya Tugana; Caykara, Tuncer; Yameen, Basit; Duran, Hatice

    Azo initiator modified surface of silica nanoparticles were coated via reversible addition-fragmentation polymerization (RAFT) of methacrylic acid and ethylene glycol dimethacrylate using 2-phenylprop 2-yl dithobenzoate as chain transfer agent. Using L-phenylalanine anilide as template during polymerization led molecularly imprinted nanoparticles. RAFT polymerization offers an efficient control of grafting process, while molecularly imprinted polymers shows enhanced capacity as sensor. L-phenylalanine anilide imprinted silica particles were characterized by X-Ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM). Performances of the particles were followed by surface plasmon resonance spectroscopy (SPR) after coating the final product on gold deposited glass substrate against four different analogous of analyte molecules: D-henylalanine anilide, L-tyrosine, L-tryptophan and L-phenylalanine. Characterizations indicated that silica particles coated with polymer layer do contain binding sites for L-phenylalanine anilide, and are highly selective for the molecule of interest. This project was supported by TUBITAK (Project No:112M804).

  3. Uranium hydrogeochemical and stream sediment reconnasissance of the Trinidad NTMS Quadrangle, Colorado, including concentrations of forty-two additional elements

    SciTech Connect

    Shannon, S.S. Jr.

    1980-05-01

    Uranium and other elemental data resulting from the Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) of the Trinidad National Topographic Map Series (NTMS) quadrangle, Colorado, by the Los Alamos Scientific Laboratory (LASL) are reported herein. This study was conducted as part of the United States Department of Energy's National Uranium Resource Evaluation (NURE), which is designed to provide improved estimates of the availability and economics of nuclear fuel resources and to make available to industry information for use in exploration and development of uranium resources. The HSSR data will ultimately be integrated with other NURE data (e.g., airborne radiometric surveys and geological investigations) to complete the entire NURE program. This report is a supplement to the HSSR uranium evaluation report for the Trinidad quadrange (Morris et al, 1978), which presented the field and uranium data for the 1060 water and 1240 sediment samples collected from 1768 locations in the quadrangle. The earlier report contains an evaluation of the uranium concentrations of the samples as well as descriptions of the geology, hydrology, climate, and uranium occurrences of the quadrange. This supplement presents the sediment field and uranium data again and the analyses of 42 other elements in the sediments. All uranium samples were redetermined by delayed-neutron counting (DNC) when the sediment samples were analyzed for 31 elements by neutron activation. For 99.6% of the sediment samples analyzed, the differences between the uranium contents first determined (Morris et al, 1978) and the analyses reported herein are less than 10%.

  4. Effect of SnO addition on optical absorption of bismuth borate glass and photocatalytic property of the crystallized glass

    SciTech Connect

    Masai, Hirokazu; Fujiwara, Takumi; Mori, Hiroshi

    2008-04-07

    We have found that an addition of SnO in a bismuth-borate glass, CaO-B{sub 2}O{sub 3}-Bi{sub 2}O{sub 3}-Al{sub 2}O{sub 3}-TiO{sub 2}, decreases the optical absorption coefficient in the visible region, in which selective crystallization of TiO{sub 2} was observed after heat treatment. Since selective crystallization of TiO{sub 2} was also attained in the SnO-containing glass, the transparency of TiO{sub 2} crystallized glass can be improved independently of selective crystallization of TiO{sub 2}. We have also demonstrated that the rutile-nanocrystallized glass with SnO addition shows a higher photocatalytic activity than the glass without SnO, indicating that this crystallized glass has a large potential for application as transparent photocatalytic materials.

  5. The research and realization of digital management platform for ultra-precision optical elements within life-cycle

    NASA Astrophysics Data System (ADS)

    Wang, Juan; Wang, Jian; Li, Lijuan; Zhou, Kun

    2014-08-01

    In order to solve the information fusion, process integration, collaborative design and manufacturing for ultra-precision optical elements within life-cycle management, this paper presents a digital management platform which is based on product data and business processes by adopting the modern manufacturing technique, information technique and modern management technique. The architecture and system integration of the digital management platform are discussed in this paper. The digital management platform can realize information sharing and interaction for information-flow, control-flow and value-stream from user's needs to offline in life-cycle, and it can also enhance process control, collaborative research and service ability of ultra-precision optical elements.

  6. Characterization of photoresist and simulation of a developed resist profile for the fabrication of gray-scale diffractive optic elements

    NASA Astrophysics Data System (ADS)

    Park, Jong Rak; Sierchio, Justin; Zaverton, Melissa; Kim, Youngsik; Milster, Tom D.

    2012-02-01

    We have characterized a photoresist used for the fabrication of gray-scale diffractive optic elements in terms of Dill's and Mack's model parameters. The resist model parameters were employed for the simulations of developed resist profiles for sawtooth patterns executed by solving the Eikonal equation with the fast-marching method. The simulated results were shown to be in good agreement with empirical data.

  7. Full vectorial simulation for characterizing loss or gain in optical devices with an accurate and automated finite-element program.

    PubMed

    Tzolov, V P; Fontaine, M; Sewell, G; Delâge, A

    1997-01-20

    An efficient, accurate, and automated vectorial finite-element method is described to characterize arbitrarily shaped optical devices having loss or gain properties. The method can be easily implemented inside the pde 2 d software environment, where an interactive session allows the user to specify the problem in a easy-to-use format. For the method to be validated, modal dispersion characteristics of high loss metal-coated optical fibers that have recently been used in applications in scanning near-field optical microscopy are presented and compared with results obtained with two vectorial approaches, i.e., the field expansion and the multiple-multipole methods. These results clearly illustrate the flexibility, accuracy, and ease of implementation of the method.

  8. Holographic optical elements (HOEs) for true-time delays aimed at phased-array antenna applications

    NASA Astrophysics Data System (ADS)

    Chen, Ray T.; Li, Richard L.

    1996-05-01

    True time-delay beam steering in optical domain for phased-array antenna application using multiplexed substrate guided wave propagation is introduced. Limitations of practical true- time-delays are discussed. Aspects on making holographic grating couplers are considered. Finally, experimental results on the generation of 25 GHz broadband microwave signals by optical heterodyne technique and 1-to-30 massive substrate guided wave optical fanout with an uniform fanout intensity distribution are presented.

  9. Effect of nitrogen addition on the structural, electrical, and optical properties of In-Sn-Zn oxide thin films

    NASA Astrophysics Data System (ADS)

    Jia, Junjun; Torigoshi, Yoshifumi; Suko, Ayaka; Nakamura, Shin-ichi; Kawashima, Emi; Utsuno, Futoshi; Shigesato, Yuzo

    2017-02-01

    Indium-tin-zinc oxide (ITZO) films were deposited at various nitrogen flow ratios using magnetron sputtering. At a nitrogen flow ratio of 40%, the structure of ITZO film changed from amorphous, with a short-range-ordered In2O3 phase, to a c-axis oriented InN polycrystalline phase, where InN starts to nucleate from an amorphous In2O3 matrix. Whereas, nitrogen addition had no obvious effect on the structure of indium-gallium-zinc oxide (IGZO) films even at a nitrogen flow ratio of 100%. Nitrogen addition also suppressed the formation of oxygen-related vacancies in ITZO films when the nitrogen flow ratio was less than 20%, and higher nitrogen addition led to an increase in carrier density. Moreover, a red-shift in the optical band edge was observed as the nitrogen flow ratio increased, which could be attributed to the generation of InN crystallites. We anticipate that the present findings demonstrating nitrogen-addition induced structural changes can help to understand the environment-dependent instability in amorphous IGZO or ITZO based thin-film transistors (TFTs).

  10. Determination of elemental carbon in lake sediments using a thermal-optical transmittance (TOT) method

    NASA Astrophysics Data System (ADS)

    Khan, A. J.; Swami, Kamal; Ahmed, Tanveer; Bari, A.; Shareef, Akhtar; Husain, Liaquat

    2009-12-01

    An improved chemical oxidation pretreatment method has been developed for the determination of elemental carbon (EC) [also known as black carbon (BC) or soot] in lake sediments, using a thermal-optical transmittance (TOT) carbon analyzer. The method employs six steps: (1) removal of carbonates by treatment with HCl; (2) removal of silicates by treatment with HF + HCl; (3) removal of any remaining carbonates by treatment with HCl; (4) removal of humic acids by treatment with NaOH; and (5) oxidation of kerogens by K 2Cr 2O 7 + H 2SO 4. A critical step of zinc chloride treatment was added; this apparently changes EC's morphology and enhances retention on quartz fiber filter, resulting in several-fold increased chemical yield. EC was determined using the TOT method with modified combustion timings. Carbon black (acetylene) and four NIST standard reference materials (SRMs) were used for quality control, and to assess the precision of the analysis. The EC recoveries from 18 carbon black samples varied from 90 to 111%, with a mean value of 99 ± 6%. The high EC recoveries confirmed the validity of the method. Char reference materials (i.e. chestnut wood and grass char) were used to determine potential contribution to EC in our measurements. The char references containing about 700 mg total organic carbon (OC) contributed ˜1.5% EC. The measured EC values from four NIST standards were 17.0 ± 0.6, 24.2 ± 3.2, 5.6, and 1.9 ± 0.1 mg g dw-1 for SRM-1648, SRM-1649a, SRM-1941b and SRM-8704, respectively. These values in SRMs were in agreement (<±4%) with the previously reported values. The method was applied to determine the EC in sediment cores from an urban lake and a remote mountain lake in the Northeastern United States. The EC concentrations in two lakes mimic the model EC emissions from the industrial revolution in United States.

  11. Predicting ambient aerosol Thermal Optical Reflectance (TOR) measurements from infrared spectra: elemental carbon

    NASA Astrophysics Data System (ADS)

    Dillner, A. M.; Takahama, S.

    2015-06-01

    Elemental carbon (EC) is an important constituent of atmospheric particulate matter because it absorbs solar radiation influencing climate and visibility and it adversely affects human health. The EC measured by thermal methods such as Thermal-Optical Reflectance (TOR) is operationally defined as the carbon that volatilizes from quartz filter samples at elevated temperatures in the presence of oxygen. Here, methods are presented to accurately predict TOR EC using Fourier Transform Infrared (FT-IR) absorbance spectra from atmospheric particulate matter collected on polytetrafluoroethylene (PTFE or Teflon) filters. This method is similar to the procedure tested and developed for OC in prior work (Dillner and Takahama, 2015). Transmittance FT-IR analysis is rapid, inexpensive, and non-destructive to the PTFE filter samples which are routinely collected for mass and elemental analysis in monitoring networks. FT-IR absorbance spectra are obtained from 794 filter samples from seven Interagency Monitoring of PROtected Visual Environment (IMPROVE) sites collected during 2011. Partial least squares regression is used to calibrate sample FT-IR absorbance spectra to collocated TOR EC measurements. The FTIR spectra are divided into calibration and test sets. Two calibrations are developed, one which is developed from uniform distribution of samples across the EC mass range (Uniform EC) and one developed from a~uniform distribution of low EC mass samples (EC < 2.4 μg, Low Uniform EC). A hybrid approach which applies the low EC calibration to low EC samples and the Uniform EC calibration to all other samples is used to produces predictions for low EC samples that have mean error on par with parallel TOR EC samples in the same mass range and an estimate of the minimum detection limit (MDL) that is on par with TOR EC MDL. For all samples, this hybrid approach leads to precise and accurate TOR EC predictions by FT-IR as indicated by high coefficient of variation (R2; 0.96), no

  12. Predicting ambient aerosol thermal-optical reflectance measurements from infrared spectra: elemental carbon

    NASA Astrophysics Data System (ADS)

    Dillner, A. M.; Takahama, S.

    2015-10-01

    Elemental carbon (EC) is an important constituent of atmospheric particulate matter because it absorbs solar radiation influencing climate and visibility and it adversely affects human health. The EC measured by thermal methods such as thermal-optical reflectance (TOR) is operationally defined as the carbon that volatilizes from quartz filter samples at elevated temperatures in the presence of oxygen. Here, methods are presented to accurately predict TOR EC using Fourier transform infrared (FT-IR) absorbance spectra from atmospheric particulate matter collected on polytetrafluoroethylene (PTFE or Teflon) filters. This method is similar to the procedure developed for OC in prior work (Dillner and Takahama, 2015). Transmittance FT-IR analysis is rapid, inexpensive and nondestructive to the PTFE filter samples which are routinely collected for mass and elemental analysis in monitoring networks. FT-IR absorbance spectra are obtained from 794 filter samples from seven Interagency Monitoring of PROtected Visual Environment (IMPROVE) sites collected during 2011. Partial least squares regression is used to calibrate sample FT-IR absorbance spectra to collocated TOR EC measurements. The FT-IR spectra are divided into calibration and test sets. Two calibrations are developed: one developed from uniform distribution of samples across the EC mass range (Uniform EC) and one developed from a uniform distribution of Low EC mass samples (EC < 2.4 μg, Low Uniform EC). A hybrid approach which applies the Low EC calibration to Low EC samples and the Uniform EC calibration to all other samples is used to produce predictions for Low EC samples that have mean error on par with parallel TOR EC samples in the same mass range and an estimate of the minimum detection limit (MDL) that is on par with TOR EC MDL. For all samples, this hybrid approach leads to precise and accurate TOR EC predictions by FT-IR as indicated by high coefficient of determination (R2; 0.96), no bias (0.00 μg m-3, a

  13. Liquid gallium metal cooling for optical elements with high heat loads

    NASA Astrophysics Data System (ADS)

    Smither, Robert K.; Forster, George A.; Kot, Christian A.; Kuzay, Tuncer M.

    1988-04-01

    The intense photon beams from the insertion devices of the Argonne Advanced Photon Source (APS) will have very high total powers, which in some cases will exceed 10 kW, spread over a few cm 2. These high heat loads will require special cooling methods for the optical elements to preserve the quality of the photon beam. A set of finite element analysis calculations were made in three dimensions to determine the temperature distributions and thermal stresses in a single crystal of silicon with heat loads of 2-20 kW. Different geometric arrangements and different cooling fluids (water, gallium, oil, Na, etc.) were considered. These data were then used in a second set of calculations to determine the distortion of the surface of the crystal and the change in the crystal plane spacing for different parts of the surface. The best heat transfer, smallest surface distortions and smallest temperature gradients on the surface of the crystals were obtained when the cooling fluid was allowed to flow through channels in the crystal. The two best fluids for room temperature operation were found to be water and liquid gallium metal. In all cases tried, the variation in temperature across the face of the crystal and the distortion of the surface was at least a factor of two less for the gallium cooling case than for the water cooling case. The water cooling was effective only for very high flow rates. These high flow rates can cause vibrations in the diffraction crystal and in its mount that can seriously degrade the quality of the diffracted photon beam. When the flow rates were decreased the gallium cooling became 3-10 times more effective. This very efficient cooling and the very low vapor pressure for liquid gallium (less than 10 -12 Torr at 100°C) make liquid gallium a very attractive cooling fluid for high vacuum synchrotron applications. A small electromagnetic induction pump for liquid Ga was built to test this cooling method. A pumping volume of 100 cm 3/s was achieved

  14. Wideband temperature-compensated optical isolator or circulator configuration using two Faraday elements.

    PubMed

    Buhrer, C F

    1989-11-01

    Two Faraday elements are configured with two linear retardation elements such that the variations in their individual rotations due to wavelength and temperature changes are compensated for. Wideband isolation between 1250 and 1650 nm is demonstrated using 45 degrees and 90 degrees yttrium iron garnet elements and two 45 degrees right-angle glass prisms (n ~ 1.73) that produce approximately 60 degrees linear retardations on total internal reflection.

  15. Research and validation of key measurement technologies of large aperture optical elements

    NASA Astrophysics Data System (ADS)

    Guo, Renhui; Chen, Lei; Jiang, Chao; Cao, Hui; Zhang, Huiqin; Zhou, Binbin; Song, Le

    2015-07-01

    A lot of optical components with large aperture are employed in high-power solid-state laser driver. These optical components are with high requirement on the surface shape, optical homogeneity and stress distribution. In order to test these parameters, different types of interferometers, surface profilers and stress meters from different manufacturers are needed. But the problem is the products from different manufacturers may provide different test results. To solve the problem, the research and verification of the key measurement technologies of large aperture optical components are carried out in this paper. The absolute flatness and optical homogeneity measurement methods are analyzed. And the test results of different interferometric software are compared. The test results from different surface profilers and stress meters are also compared. The consistency and reliability of different test software are obtained with the comparing results, which will guide users to select a suitable product.

  16. A Closed-Cycle Optical Cryostat and Improved Optical Elements for Studies of Dissipation at the Molecular Scale

    DTIC Science & Technology

    2016-02-05

    MONITORING AGENCY NAME(S) AND ADDRESS (ES) U.S. Army Research Office P.O. Box 12211 Research Triangle Park, NC 27709-2211 plasmonics , optical cryostat...none) 02/03/2016 02/03/2016 Received Paper 1.00 2.00 Kenneth M. Evans, Pavlo Zolotavin, Douglas Natelson. Plasmon -Assisted Photoresponse in Ge-Coated...Zolotavin, Douglas Natelson. Plasmonic Heating in Au nanowires at Low Temperatures, ACS Nano (02 2016) TOTAL: 1 Books Number of Manuscripts: Patents

  17. Measuring Productive Elements of Multi-Word Phrase Vocabulary Knowledge among Children with English as an Additional or Only Language

    ERIC Educational Resources Information Center

    Smith, Sara A.; Murphy, Victoria A.

    2015-01-01

    Vocabulary plays a critical role in language and reading development for children, particularly those learning English as an additional language (EAL) (Stahl & Nagy, 2006). Previous research on vocabulary has mainly focused on measuring individual words without considering multi-word phrase knowledge, despite evidence that these items occur…

  18. THE LATTICE PARAMETERS AND SOLUBILITY LIMITS OF ALPHA IRON AS AFFECTED BY SOME BINARY TRANSITION-ELEMENT ADDITIONS.

    DTIC Science & Technology

    The lattice parameters of alpha iron with binary additions of all the transition metals, except technetium, have been accurately determined on solid...samples. No direct correlation with solute size is observed, but an effect of electron configuration is noted. The solubility limits of alpha iron with

  19. Biochemical methane potential from sewage sludge: Effect of an aerobic pretreatment and fly ash addition as source of trace elements.

    PubMed

    Huiliñir, César; Pinto-Villegas, Paula; Castillo, Alejandra; Montalvo, Silvio; Guerrero, Lorna

    2017-03-18

    The effect of aerobic pretreatment and fly ash addition on the production of methane from mixed sludge is studied. Three assays with pretreated and not pretreated mixed sludge in the presence of fly ash (concentrations of 0, 10, 25, 50, 250 and 500mg/L) were run at mesophilic condition. It was found that the combined use of aerobic pretreatment and fly ash addition increases methane production up to 70% when the fly ash concentrations were lower than 50mg/L, while concentrations higher than 250mg/L cause up to 11% decrease of methane production. For the anaerobic treatment of mixed sludge without pretreatment, the fly ash improved methane generation at all the concentrations studied, with a maximum of 56%. The removal of volatile solids does not show an improvement compared to the separate use of an aerobic pre-treatment and fly ash addition. Therefore, the combined use of the aerobic pre-treatment and fly ash addition improves only the production of methane.

  20. Re-evaluating the tephrochronology of the Palouse Loess, Washington State, using optically stimulated luminescence dating and single-shard major- and trace-element analyses

    NASA Astrophysics Data System (ADS)

    King, G. E.; Roberts, H. M.; Pearce, N. J.; Gaylord, D.; Sweeney, M.; Duller, G. A.; Smith, V.

    2013-12-01

    Tephra derived from Mount St Helens (MSH) are a critical component of the tephrochronology of the Palouse Loess region, Washington State, USA. New analyses of both source-proximal and -distal tephra units from Washington State using paired major-element and LA-ICP-MS trace-element geochemistry have been undertaken. These analyses reveal that MSH tephra commonly employed to constrain the timing of loess deposition, including tephra from MSH eruptive sets S (~16 ka) and M (~22 ka), cannot be differentiated using major-element chemistry alone. Further, some distal tephra in the Palouse Loess which were previously assigned as MSH Set S on the basis of major-element geochemistry or stratigraphy are now suggested through trace-element analysis to be other tephra, including MSH Set M. Additional support for this re-evaluation of these Palouse Loess tephra units has been provided by luminescence dating of loess that brackets the tephra units. Single-aliquot optically stimulated luminescence (OSL) methods developed for quartz (e.g. Wintle and Murray, 2006), and a new method proposed for dating feldspars (Thomsen et al., 2008; using the ';post-IR IRSL' signal) have been applied at several sites. The ages generated are stratigraphically consistent within each site, and show agreement between the two luminescence methods. Whilst these newly generated luminescence ages are not consistent in all cases with previously published tephra assignments, they are consistent with the revised tephrochronology proposed on the basis of new trace-element geochemistry. This combination of major- plus trace-element geochemistry and luminescence chronology provides a coherent picture of the tephrochronology of the sites examined in the Palouse. More broadly, this highlights the importance of combining both detailed geochemistry and geochronology in areas where tephra are geochemically indistinct. References Wintle A.G. and Murray, A.S., 2006. A review of quartz optically stimulated luminescence

  1. Optical and other property changes of M-50 bearing steel surfaces for different lubricants and additive prior to scuffing

    NASA Technical Reports Server (NTRS)

    Lauer, J. L.; Marxer, N.

    1984-01-01

    An ester lubricant base oil containing one or more standard additives to protect against wear, corrosion, and oxidation was used in an experimental ball/plate elastohydrodynamic contact under load and speed conditions such as to induce scuffing failure in short times. Both the ball and the plate were of identically treated M-50 steel. After various periods of operating time the wear track on the plate was examined with an interference microscope of plus or minus 30 A depth resolution and sometimes also with a scanning ellipsometer and an Auger spectrometer. The optically deduced surface profiles varied with wavelength, indicating the presence of surface coatings, which were confirmed by the other instruments. As scuffing was approached, a thin (approximately A) oxide layer and a carbide layer formed in the wear track in particular when tricresylphosphate antiwear additive was present in the lubricant. The rates of the formation of these layers and their reactivity toward dilute alcholic HCl depended strongly on the lubricant and additives. Based on these results suggestions for improved formulations and a test method for bearing reliability could be proposed.

  2. Uranium hydrogeochemical and stream sediment reconnaissance of the Newcastle NTMS quadrangle, Wyoming, including concentrations of forty-two additional elements

    SciTech Connect

    Goff, S.J.; Sandoval, W.F.; Gallimore, D.L.; Talcott, C.L.; Martinez, R.G.; Minor, M.E.; Mills, C.F.

    1980-06-01

    During the summer and fall of 1977, 533 water and 1226 sediment samples were collected from 1740 locations within the 18,000 km/sup 2/ area of the Newcastle quadrangle, Wyoming. Water samples were collected from wells and springs; sediment samples were collected from stream channels and from springs. Each water sample was analyzed for uranium, and each sediment sample was analyzed for 43 elements, including uranium and thorium. Uranium concentrations in water samples range from below the detection limit of 0.02 ppB to 702.26 ppB and have a median of 1.73 ppB and a mean of 11.76 ppB. Water samples containing high uranium concentrations (>20 ppB) generally are associated with known uranium mining activity or units known to be uranium bearing. About one-third of the water samples containing high uranium concentrations were collected from locations within the Pumpkin Buttes and Turnercrest-Ross Districts. Nearly half of the water samples containing high uranium concentrations were collected from locations just west of the Monument Hill and Highland Flats-Box Creek Districts. Similar anomalous uranium concentrations in this region have been reported updip from Exxon's Highland uranium deposits. High uranium concentrations were also found associated with the Lance Creek-Old Woman Anticline District.

  3. Weak scratch detection and defect classification methods for a large-aperture optical element

    NASA Astrophysics Data System (ADS)

    Tao, Xian; Xu, De; Zhang, Zheng-Tao; Zhang, Feng; Liu, Xi-Long; Zhang, Da-Peng

    2017-03-01

    Surface defects on optics cause optic failure and heavy loss to the optical system. Therefore, surface defects on optics must be carefully inspected. This paper proposes a coarse-to-fine detection strategy of weak scratches in complicated dark-field images. First, all possible scratches are detected based on bionic vision. Then, each possible scratch is precisely positioned and connected to a complete scratch by the LSD and a priori knowledge. Finally, multiple scratches with various types can be detected in dark-field images. To classify defects and pollutants, a classification method based on GIST features is proposed. This paper uses many real dark-field images as experimental images. The results show that this method can detect multiple types of weak scratches in complex images and that the defects can be correctly distinguished with interference. This method satisfies the real-time and accurate detection requirements of surface defects.

  4. Uranium hydrogeochemical and stream sediment reconnaissance of the Newcastle NTMS Quadrangle, Wyoming, including concentrations of forty-two additional elements

    SciTech Connect

    Goff, S.J.; Sandoval, W.F.; Gallimore, D.L.; Talcott, C.L.; Martinez, R.G.; Minor, M.E.; Mills, C.F.

    1980-06-01

    Water and sediment samples were collected and each water sample was analyzed for U, and each sediment sample was analyzed for 43 elements, including U and Th. Uranium concentrations in water samples range from below the detection limit of 0.02 ppB to 702.26 ppB and have a median of 1.73 ppB and a mean of 11.76 ppB. Water samples containing high uranium concentrations generally are associated with known uranium mining activity or units known to be uranium bearing. About one-third of the water samples containing high uranium concentrations were collected from locations within the Pumpkin Buttes and Turnercrest-Ross Districts. Nearly half of the water samples containing high uranium concentrations were collected from locations just west of the Monument Hill and Highland Flats-Box Creek Districts. Similar anomalous uranium concentrations in this region have been reported updip from Exxon's Highland uranium deposits. High uranium concentrations were also found associated with the Lance Creek-Old Woman Anticline District. Uranium concentrations in sediment samples range from 1.14 to 220.70 ppM and have a median of 3.37 ppM and a mean of 4.03 ppM. Throughout the major uranium mining districts of the Powder River Basin, sediment samples with high uranium concentrations were collected from dry streams located near wells producing water samples with high uranium concentrations. High uranium concentrations were also found associated with the Lance Creek oil field where uranium mineralization is known in the White River formation. High uranium concentrations were also found in sediment samples in areas where uranium mineralization is not known. These samples are from dry streams in areas underlain by the White River formation, the Niobrara formation, and the Pierre, Carlisle, Belle Fourche, and Mowry shales.

  5. Optical full-depth refocusing of 3-D objects based on subdivided-elemental images and local periodic δ-functions in integral imaging.

    PubMed

    Ai, Ling-Yu; Dong, Xiao-Bin; Jang, Jae-Young; Kim, Eun-Soo

    2016-05-16

    We propose a new approach for optical refocusing of three-dimensional (3-D) objects on their real depth without a pickup-range limitation based on subdivided-elemental image arrays (sub-EIAs) and local periodic δ-function arrays (L-PDFAs). The captured EIA from the 3-D objects locating out of the pickup-range, is divided into a number of sub-EIAs depending on the object distance from the lens array. Then, by convolving these sub-EIAs with each L-PDFA whose spatial period corresponds to the specific object's depth, as well as whose size is matched to that of the sub-EIA, arrays of spatially-filtered sub-EIAs (SF-sub-EIAs) for each object depth can be uniquely extracted. From these arrays of SF-sub-EIAs, 3-D objects can be optically reconstructed to be refocused on their real depth. Operational principle of the proposed method is analyzed based on ray-optics. In addition, to confirm the feasibility of the proposed method in the practical application, experiments with test objects are carried out and the results are comparatively discussed with those of the conventional method.

  6. [Finite element analysis of electric field of extracellular stimulation of optic nerve with a spiral cuff electrode].

    PubMed

    Guo, Hongwei; Qiao, Qingli; Luo, Fang

    2012-10-01

    In order to study the underlying electrode-nerve functional mechanism, optimize the electrode design and guide the prosthesis application, we applied finite element method to analyze the spatial distribution of electric field generated by optic nerve electrical stimulation with spiral cuff electrode. A macroscopic cylindrical model of optic nerve was elaborated, taking into account of electrode contact configurations and possible variations of the thickness of cerebrospinal fluid (CSF). By building an appropriate mesh on this model and under some boundary conditions, the finite element method was applied to compute the 3D electric field generated by the electrode with finite element software COMSOL Multiphysics. The stimulation results indicated that, under the same conditions of stimulation, the longitudinal tripolar electrode structure could generate larger current density than that of biopolar electrode structure (located in the opposite of nerve trunk). However biopolar electrode structure requirs less leads, and is more easily implanted. By means of parametric sweep, the results suggest that, with the increase of the CSF thickness and a higher conductivity of CSF than those of other tissues, the distribution of electric field generated by electrodes is extended but scattered, and the diffuse current distribution makes nerve stimulation less effective.

  7. Fabrication of optical element from unidirectional grown imidazole-imidazolium picrate monohydrate (IIP) organic crystals for nonlinear optical applications

    NASA Astrophysics Data System (ADS)

    Vivek, P.; Murugakoothan, P.

    2014-12-01

    Nonlinear optical bulk single crystal of Imidazole-imidazolium picrate monohydrate (IIP) has been grown by Sankaranarayanan-Ramasamy (SR) method using acetonitrile as solvent. First time we report the bulk growth of IIP crystal by SR method. The transparent IIP single crystal of maximum diameter 21 mm and length 46 mm was obtained by employing SR method. The grown crystal was subjected to high resolution X-ray diffraction, UV-vis-NIR transmittance, refractive index, hardness, dielectric and laser damage threshold studies. The crystalline perfection of the grown crystal was analyzed using HRXRD. Cut off wavelength and optical transmission window of the crystal was assessed by UV-vis-NIR and the refractive index of the crystal was found. The mechanical property of the crystal was estimated by Vicker's hardness test. The dielectric property of the crystal was measured as a function of frequency. The laser damage threshold value was determined. The particle size dependent second harmonic generation efficiency for IIP was evaluated with standard reference material potassium dihydrogen phosphate (KDP) by Kurtz-Perry powder method using Nd:YAG laser, which established the existence of phase matching. The second harmonic generation (SHG) of IIP crystal was investigated by the SHG Maker fringes technique. The mechanism of growth is revealed by carrying out chemical etching using acetonitrile as etchant.

  8. The atomic-scale mechanism for the enhanced glass-forming-ability of a Cu-Zr based bulk metallic glass with minor element additions

    NASA Astrophysics Data System (ADS)

    Wang, Q.; Liu, C. T.; Yang, Y.; Liu, J. B.; Dong, Y. D.; Lu, J.

    2014-04-01

    It is known that the glass forming-ability (GFA) of bulk metallic glasses (BMGs) can be greatly enhanced via minor element additions. However, direct evidence has been lacking to reveal its structural origin despite different theories hitherto proposed. Through the high-resolution transmission-electron-microscopy (HRTEM) analysis, here we show that the content of local crystal-like orders increases significantly in a Cu-Zr-Al BMG after a 2-at% Y addition. Contrasting the previous studies, our current results indicate that the formation of crystal-like order at the atomic scale plays an important role in enhancing the GFA of the Cu-Zr-Al base BMG.

  9. Antenna Gain Enhancement and Beamshaping using a Diffractive Optical Element (DOE) Lens

    NASA Astrophysics Data System (ADS)

    Torbitt, Christopher

    Dielectric and metamaterial lenses have been designed for gain enhancement and beam shaping. The motivation for this work came from a commercially available slotted waveguide antenna with a dielectric lens that shapes the beam and enhances the gain only in the azimuth plane. When two of these antennas, each with a dielectric lens, are stacked as an array to form the sum and difference patterns the elevation plane gain is low and the beam width too wide to be acceptable for radar applications. The objective of the present work is to design a diffractive optical element (DOE) lens for gain enhancement gain and beam shaping. As compared to other available lenses it is much thinner, lighter and easily machined. The DOE lens is made from rexolite which has a dielectric constant of 2.53. The DOE lens is composed of a series of zones which focus the light at a certain focal length. The phase is the same everywhere on each zone at the focal point. The phase difference between neighboring zones is 2pi, resulting in a constructive interference at the focus. These zones are able to focus the radiation from an antenna in order to enhance the gain and shape the beam. The design parameters include the lens diameter, number of zones, the center zone thickness for a particular frequency and refractive index of the dielectric material. A comprehensive study has been performed in CST Microwave Studio to illustrate the properties of the DOE lens. The focusing property for image formation is verified by a plane wave excitation. Lenses have been designed and tested at different frequencies and with varying design parameters. Gain enhancement and beam shaping are illustrated by modeling the DOE lens in CST and placing it in front of different antennas. This work presents lenses for 10GHz and 40GHz horn antennas, a 3GHz slotted waveguide antenna array, and a 10GHz microstrip patch arrays. Beam shaping and focusing is clearly illustrated for each type of antenna. It is seen that the size

  10. Rapid detection of delamination areas in laminated structural elements by means of optically monitored strain solitons

    NASA Astrophysics Data System (ADS)

    Semenova, I. V.; Belashov, A. V.; Dreiden, G. V.; Petrov, N. V.; Samsonov, A. M.

    2015-05-01

    Modern structural elements are often made of laminated polymer materials or composites on the base of polymer matrices. The proper functioning of these elements may be of vital importance especially in automotive and aerospace industries, in gas and oil transportation. The major problem in their performance is a possibility of a sudden and irreversible delamination caused by various factors. We propose and study a NDT approach aimed to detect delamination areas in adhesively bonded layered structural elements made of different materials. The proposed approach is evaluated by use of holographic detection and monitoring of the evolution of bulk strain solitons generated in such structures.

  11. Self-compensating fiber optic flow sensor having an end of a fiber optics element and a reflective surface within a tube

    DOEpatents

    Peng, Wei; Qi, Bing; Wang, Anbo

    2006-05-16

    A flow rate fiber optic transducer is made self-compensating for both temperature and pressure by using preferably well-matched integral Fabry-Perot sensors symmetrically located around a cantilever-like structure. Common mode rejection signal processing of the outputs allows substantially all effects of both temperature and pressure to be compensated. Additionally, the integral sensors can individually be made insensitive to temperature.

  12. Universal Three-Qubit Entanglement Generation Based on Linear Optical Elements and Quantum Non-Demolition Detectors

    NASA Astrophysics Data System (ADS)

    Liu, Xin-Chang

    2016-12-01

    Recently, entanglement plays an important role in quantum information science. Here we propose an efficient and applicable method which transforms arbitrary three-qubit unknown state to a maximally entangled Greenberger-Horne-Zeilinger state, and the proposed method could be further generalized to multi-qubit case. The proposed setup exploits only linear optical elements and quantum non-demolition detectors using cross-Kerr media. As the quantum non-demolition detection could reveal us the output state of the photons without destroying them. This property may make our proposed setup flexible and can be widely used in current quantum information science and technology.

  13. Universal Three-Qubit Entanglement Generation Based on Linear Optical Elements and Quantum Non-Demolition Detectors

    NASA Astrophysics Data System (ADS)

    Liu, Xin-Chang

    2017-02-01

    Recently, entanglement plays an important role in quantum information science. Here we propose an efficient and applicable method which transforms arbitrary three-qubit unknown state to a maximally entangled Greenberger-Horne-Zeilinger state, and the proposed method could be further generalized to multi-qubit case. The proposed setup exploits only linear optical elements and quantum non-demolition detectors using cross-Kerr media. As the quantum non-demolition detection could reveal us the output state of the photons without destroying them. This property may make our proposed setup flexible and can be widely used in current quantum information science and technology.

  14. Direct determination of trace elements in tungsten products using an inductively coupled plasma optical emission charge coupled device detector spectrometer

    NASA Astrophysics Data System (ADS)

    Xiuhuan, Yang; Jinfang, Wei; Hongtao, Liu; Baoying, Tang; Zhanxia, Zhang

    1998-09-01

    An echelle inductively coupled plasma optical emission spectrometer equipped with a segmented array of charge coupled device detectors was used for the direct determination of trace impurities in tungsten products. No sample preparation was necessary. The multicomponent spectral fitting software provided by the instrument was used for the correction of spectral interference and background. The detection limits of the trace elements Al, As, Bi, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Ni, P, Pb, Sb, Sn, Ti and V in tungsten matrix were obtained under optimized operating conditions. The accuracy of the proposed method was assessed using three National Reference Materials. As a result of their ultra-trace concentrations in the reference materials, As, Pb and Sn could not be determined satisfactorily. The concentrations found for the other elements agreed quite well with those of the certified values of the reference materials.

  15. Mechanical properties and phase composition of potential biodegradable Mg-Zn-Mn-base alloys with addition of rare earth elements

    SciTech Connect

    Stulikova, Ivana; Smola, Bohumil

    2010-10-15

    Mechanical properties and creep resistance of the MgY4Zn1Mn1 alloy in the as cast as well as in the T5 condition were compared to those of the MgCe4Zn1Mn1 alloy in the same conditions. Yield tensile stress and ultimate tensile strength of the MgY4Zn1Mn1 alloy are slightly better in the temperature range 20 deg. C-400 deg. C than these of the MgCe4Zn1Mn1 alloy. Better thermal stability of ultimate tensile strength was observed in the T5 treated MgCe4Zn1Mn1 alloy than in this material in the as cast condition. An outstanding creep resistance at 225 deg. C-350 deg. C found in the MgY4Zn1Mn1 alloy is due to the existence of the 18R long period stacking structure persisting in this alloy even a long heat treatment of 500 deg. C/32 h. No similar stacking effects happen when Ce substitutes Y in approximately the same concentration. The creep resistance deteriorates considerably in the MgCe4Zn1Mn1 alloy. Rectangular particles of the equilibrium Mg{sub 12}Ce phase dominate in the microstructure of as cast as well as of high temperature heat-treated MgCe4Zn1Mn1 alloy. A population of small oval particles containing Mg and Zn develops additionally during annealing of this alloy. These particles pin effectively dislocations and can be responsible for the better thermal stability of the T5 treated material.

  16. Effect of surfactant addition on ultrasonic leaching of trace elements from plant samples in inductively coupled plasma-atomic emission spectrometry

    NASA Astrophysics Data System (ADS)

    Borkowska-Burnecka, Jolanta; Jankowiak, Urszula; Zyrnicki, Wieslaw; Anna Wilk, Kazimiera

    2004-04-01

    The applicability of surfactants in sample preparation of plant materials followed by analysis by inductively coupled plasma atomic emission spectrometry has been examined. Reference materials (INCT-MPH-2-Mixed Polish Herbs, INCT-TL-1 black tea leaves and CTA-VTL-2 -Virginia tobacco leaves) and commercially available tea leaves were analyzed. Effects of addition surfactants (Triton X-100, didodecyldimethylammonium bromide and cetyltrimethylammonium bromide) on efficiency of ultrasonic leaching of elements from the plant samples and on plasma parameters were investigated. Low concentrations of the surfactants in solutions did not affect, in practice, analytical line intensities and the nebulization process. Quantitative recovery of some elements could be obtained by ultrasonic diluted acid leaching with the aid of surfactants. However, the element recovery depended on type of surfactant, as well as element and sample material. Plasma parameters, i.e. the excitation temperatures of Ar I, Fe II and Ca II as well as the electron number density and the Mg II/Mg I intensity ratio did not vary significantly due to the surfactants in solutions.

  17. Use of living technical budgets to manage risk on the James Webb Space Telescope optical element

    NASA Astrophysics Data System (ADS)

    Porpora, Daniel A.; Barto, Allison A.; Lightsey, Paul A.; Knight, J. Scott

    2016-07-01

    The James Webb Space Telescope (JWST) Primary Mirror (PM) and Secondary Mirror (SM) are deployable relative to the rest of the optics. The PM consists of 18 assemblies which are aligned on-orbit using hexapod actuators. The complexity introduces risk that misalignments of individual components could result in a system with an unexpected optical train. In order to monitor risk throughout the life of the project, a series of interrelated technical budgets and independent cross-checks have been created and are continually updated with as-built data to provide confidence in the state of the system as well as the path to completion.

  18. Strain of optic-fiber/giant magnetostrictive film structure in magnetic field by finite element analysis

    NASA Astrophysics Data System (ADS)

    Hu, Jiafei; Pan, Mengchun; Xin, Jianguang; Chen, Dixiang

    2008-12-01

    The magnetostrictive transducer is the most important part of the optic-fiber magnetic field sensor, and the optic-fiber/giant magnetostrictive(GMS) film coupled structure is a novel coupling form of the magnetostrictive transducer. Always we analyze the coupled structure based on the entire coupled structure being sputtered GMS material without tail-fibers. In practical application, the coupled structure has tail-fibers without films at two ends. When the entire coupled structure is immersed in the detected magnetic field, the detected magnetic field causes the GMS film strain then causing optic-fiber strain. This strain transmission process is different from it in the coupled structure entirely with GMS films without tail-fibers. The strain transmission relationship can be calculated theoretically in the coupled structure without tail-fibers, but it's complicated to theoretically calculate the strain transmission relationship in the coupled structure with tail-fibers. After large numbers of calculations and analyses by ANSYS software, we figure out some relationships of the two strain transmission processes in the respective structures and the stress distribution in the tail-fibers. These results are helpful to the practical application of the optic-fiber/ GMS film coupled structure.

  19. Reconfigurable Optical Elements Based on Single and Coupled Microdisk Resonators with Quantum DOT Active Media

    DTIC Science & Technology

    2012-06-29

    successfully demonstrated (i) incorporation of CdSe QDs into polymer and dielectric host and realization of devices such as active waveguides , microdisk...14) These values are used as initial approximations for each of the two possible solutions. Results of numerical solution of Eq...between dielectric layers without having detrimental effect on the optical properties of the QDs. Characterization and Modeling By controlling

  20. Standards: a key element of optical design, engineering productivity, and time to market

    NASA Astrophysics Data System (ADS)

    Youngworth, Richard N.; Kiontke, Sven R.; Aikens, David M.

    2014-12-01

    Standards provide a conduit for understanding and communication in the global optics industry. Proper use and knowledge of standards is beneficial to global commerce and increases productivity. In this paper the design utility and efficiency afforded by standards is shown with examples that are congruent with current ANSI and ISO published documents.

  1. Optical current sensing element with single medium layers for high voltage applications

    NASA Astrophysics Data System (ADS)

    Wang, Z. P.; Huang, Z. J.; Kang, C.; Sun, W. M.; Ruan, S. L.; Luo, Y. H.; Palmer, A. W.; Grattan, K. T. V.

    1999-09-01

    The performance of a Faraday current sensing element with single medium layer coatings with potential for use at high voltage is reported, and the principle and the design parameters of the polarization-preserving, totally reflecting, single medium layer are given. The performance of the sensing element is demonstrated, showing a sensitivity of approximately 90% of the theoretically achievable maximum for an ideal case, a ratio error of 0.33% over a 7 h stability period and a 21 dB EMI immunity. Some of the advantages of this design are considered and discussed.

  2. The use of optical fibers in the Trans Iron Galactic Element Recorder (TIGER)

    SciTech Connect

    Sposato, S. H.; Binns, W. R.; Dowkontt, P. F.; Epstein, J. W.; Hink, P. L.; Israel, M. H.; Klarmann, J.; Lawrence, D. J.; Barbier, L. M.; Christian, E. R.; Mitchell, J. W.; Streitmatter, R. E.; Nolfo, G. A. de; Mewaldt, R. A.; Shindler, S. M.; Waddington, C. J.

    1998-11-09

    TIGER, the Trans-Iron Galactic Element Recorder, is a cosmic-ray balloon borne experiment that utilizes a scintillating Fiber Hodoscope/Time of Flight (TOF) counter. It was flown aboard a high altitude balloon on September 24, 1997. The objective of this experiment is to measure the elemental abundances of all nuclei within the charge range: 26{<=}Z{<=}40. This initial balloon flight will test the detector concept, which will be used in future balloon and space experiments. The instrument and the fiber detector are described.

  3. Impact of trace element addition on degradation efficiency of volatile fatty acids, oleic acid and phenyl acetate and on microbial populations in a biogas digester.

    PubMed

    Karlsson, Anna; Einarsson, Peter; Schnürer, Anna; Sundberg, Carina; Ejlertsson, Jörgen; Svensson, Bo H

    2012-10-01

    The effect of trace element addition on anaerobic digestion of food industry- and household waste was studied using two semi-continuous lab-scale reactors, one (R30+) was supplied with Fe, Co and Ni, while the other (R30) acted as a control. Tracer analysis illustrated that methane production from acetate proceeded through syntrophic acetate oxidation (SAO) in both digesters. The effect of the trace elements was also evaluated in batch assays to determine the capacity of the microorganisms of the two digesters to degrade acetate, phenyl acetate, oleic acid or propionate, butyrate and valerate provided as a cocktail. The trace elements addition improved the performance of the process giving higher methane yields during start-up and early operation and lower levels of mainly acetate and propionate in the R30+ reactor. The batch assay showed that material from R30+ gave effects on methane production from all substrates tested. Phenyl acetate was observed to inhibit methane formation in the R30 but not in the R30+ assay. A real-time PCR analysis targeting methanogens on the order level as well as three SAO bacteria showed an increase in Methanosarcinales in the R30+ reactor over time, even though SAO continuously was the dominating pathway for methane production. Possibly, this increase explains the low VFA-levels and higher degradation rates observed in the R30+ batch incubations. These results show that the added trace elements affected the ability of the microflora to degrade VFAs as well as oleic acid and phenyl acetate in a community, where acetate utilization is dominated by SAO.

  4. Modified sensing element of a fibre-optic current sensor based on a low-eigenellipticity spun fibre

    SciTech Connect

    Przhiyalkovsky, Ya V; Morshnev, S K; Starostin, N I; Gubin, V P

    2014-10-31

    We have proposed and investigated a modified sensing element of a spun fibre current sensor for the case when the beat length of the built-in linear birefringence of the fibre is equal to or less than the spin pitch of its helical structure. The proposed configuration makes it possible to restore the interferometer contrast reduced because of the decrease in the ellipticity of the wavelength-averaged polarisation state of radiation propagating in such spun fibre. The modified sensing element contains two polarisation state converters: one, located at the spun fibre input, produces polarisation with ellipticity equal to the eigenellipticity of the fibre, and the other ensures conversion of the elliptical polarisation to an orthogonal one through mirror reflection at the fibre output. We have also demonstrated that the magneto-optical sensitivity decreases slightly for the analysed spectrum-averaged parameters of the polarisation state of radiation in the spun fibre. Experimental data lend support to the theoretical predictions. (fibre-optic sensors)

  5. Long-term laser irradiation tests of optical elements for ESA mission ADM-Aeolus

    NASA Astrophysics Data System (ADS)

    Leinhos, Uwe; Mann, Klaus; Bayer, Armin; Endemann, Martin; Wernham, Denny; Pettazzi, Federico; Thibault, Dominique

    2010-08-01

    The European Space Agency ESA is running a series of earth observation missions. In order to perform global windprofile observation based on Doppler-LIDAR, the satellite ADM-Aelolus will be launched in April 2011 and injected into an orbit 400 km above Earth's surface. ADM-Aeolus will be the first satellite ever that is equipped with a UV-laser (emitting at 355 nm) and a reflector telescope. At LLG, a setup was developed that allows monitoring transmission, reflection and fluorescence of laser-irradiated optical components, in order to assess their possible optical degradation due to radiation-induced contaminant deposition in orbit. For both a high-reflecting mirror and an anti-reflective coated window long-term irradiation tests (up to 500 million laser pulses) were performed at a base pressure < 10-9 mbar, using a XeF excimer laser (wavelength 351 nm, repetition rate 1kHz). At this, samples of polymers used inside the satellite (insulators for cabling, adhesives, etc.) were installed into the chamber, and the interaction of their degassing with the sample surfaces under laser irradiation was investigated. Various paramters were varied including pulse repetition rate, view factor and coatings. Optical degradation associated with contaminant adsorption was detected on the irradiated sample sites.

  6. Diffractive optical elements with an increased angular and wavelength range of operation for application in solar collectors

    NASA Astrophysics Data System (ADS)

    Akbari, H.; Naydenova, I.; Martin, S.

    2015-05-01

    A holographic device characterised by a large angular and wavelength range of operation is under development. It aims to improve the efficiency of solar energy concentration in solar cells. The aim of this study is to increase the angular and wavelength range of the gratings by stacking three layers of high efficiency gratings on top of each other so that light from a moving source, such as the sun, is collected from a broad range of angles. In order to increase the angle and the wavelength range of operation of the holographic device, low spatial frequency of holographic recording is preferable. Recording at low spatial frequency requires a photopolymer material with unique properties, such as fast monomer/monomers diffusion rate/rates. An acrylamide-based photopolymer developed at the Centre for Industrial and Engineering Optics has been used in this study. This material has fast diffusion rates and has previously demonstrated very good performance at low spatial frequency, where gratings of 90% diffraction efficiency at 300 lines/ mm spatial frequency were recorded in layers of 75 μm thickness. This paper will study the angular selectivity of a device consisting of stacked layer of Difftactive Optical Elements ( DOEs) recorded at range of angles at spatial frequency of 300 lines/mm with recording intensity of 1 mW/cm2. The optical recording process and the properties of the multilayer structure are described and discussed.

  7. Exterior optical cloaking and illusions by using active sources: A boundary element perspective

    NASA Astrophysics Data System (ADS)

    Zheng, H. H.; Xiao, J. J.; Lai, Y.; Chan, C. T.

    2010-05-01

    Recently, it was demonstrated that active sources can be used to cloak any objects that lie outside the cloaking devices [F. Guevara Vasquez, G. W. Milton, and D. Onofrei, Phys. Rev. Lett. 103, 073901 (2009)]. Here, we propose that active sources can create illusion effects so that an object outside the cloaking device can be made to look like another object. Invisibility is a special case in which the concealed object is transformed to a volume of air. From a boundary element perspective, we show that active sources can create a nearly “silent” domain which can conceal any objects inside and at the same time make the whole system look like an illusion of our choice outside a virtual boundary. The boundary element method gives the fields and field gradients, which can be related to monopoles and dipoles, on continuous curves which define the boundary of the active devices. Both the cloaking and illusion effects are confirmed by numerical simulations.

  8. Specification of the surface figure and finish of optical elements in terms of system performance

    SciTech Connect

    Church, E.L.; Takacs, P.Z.

    1992-09-01

    Brookhaven National Laboratory is the site of the National Synchrotron Light Source (NSLS); an electron synchrotron which is an intense source of hard and soft x-rays. Since there are no effective refracting elements for x rays, this radiation must be manipulated and focused by mirrors configured to give high reflectivity. This paper describes methods of predicting the degradation of the performance of a simple imaging system in terms of the statistics of the shape errors of the focusing element, and conversely, of specifying those statistics in terms of requirements on image quality. Results are illustrated for a normal-incidence x-ray mirrors having figure errors plus conventional and/or fractal finish errors.

  9. Effects of TiO2 and Co2O3 combination additions on the elemental distribution and electromagnetic properties of Mn-Zn power ferrites

    NASA Astrophysics Data System (ADS)

    Yang, W. D.; Wang, Y. G.

    2015-06-01

    The effects of TiO2 and Co2O3 combination additions on the elemental distribution and electromagnetic properties of Mn-Zn power ferrites are investigated. TiO2 addition can promote Co2O3 transfer from grain boundaries to the bulk of the grains. The temperature at which the highest initial permeability μi and the lowest power losses PL appear shifts to low temperature range with the increase of Co2O3 content. Compared with the reference sample without TiO2 and Co2O3 addition, the microstructure and electromagnetic properties of Mn-Zn power ferrites can be considerably improved with suitable amounts of TiO2 and Co2O3 combination additions. At the peak temperature, the sample with the 0.1 wt% TiO2 and 0.08 wt% Co2O3 additions has an increase of 15.8% in μi to 3951, and a decrease of 22.9% in PL to 286 kW/m3. The saturation magnetic induction Bs and electrical resistivity ρ at 25 °C reach the highest values of 532 mT and 8.12 Ω m, respectively.

  10. System of the optic-electronic sensors for control position of the radio telescope elements

    NASA Astrophysics Data System (ADS)

    Konyakhin, Igor; Stepashkin, Ivan; Petrochenko, Andrey

    2016-04-01

    A promising area of modern astronomy is the study of the field of millimeter waves. The use of this band is due to a large extent the spectrum characteristics of the propagation of waves in the atmosphere, short wavelength. Currently, Russia jointly with Uzbekistan is implementing a project to build a radio astronomy observatory on the Suffa plateau (Uzbekistan). The main instrument of the observatory is fully steerable radio telescope RT-70 type. Main mirror telescope is a fragment of an axisymmetric parabolic with a focal length of 21 m, consisting of 1200 reflecting panels; main mirror diameter - 70 m; diameter of counter reflector - 3 m. A feature of the radio telescope as a means of research in the millimeter wavelength range are high for the quality requirements parabolic surface of the primary mirror (standard deviation of points on the surface of the theoretical parabolic is not more than 0.05 mm), to the stability of the mutual arrangement of the primary mirror and the counter reflector (not more than 0, 07 mm) for precision guidance in the corners of the mirror system azimuth and elevation (margin of error 1.5-2"). Weight of structure, temperature changes and air shock result in significant deformation elements radio telescope construction (progressive linear displacements of points of the surface of the main mirror), reaching in the marginal zone of 30 mm; counter reflector shift of up to 60 mm; Unlike the angular position of the axis of the beam pattern of the radio telescope of the measured angle transducers can reach 10 ". Therefore, to ensure the required quality of the reflective elements RT-70 systems, as well as the implementation of precision-guided munitions needs complex measuring deformation elements telescope design. This article deals with the construction of opto-electronic system of remote optoelectronic displacement sensor control elements mirror telescope system.

  11. Miniature lightweight X-ray optics (MiXO) for surface elemental composition mapping of asteroids and comets

    NASA Astrophysics Data System (ADS)

    Hong, Jaesub; Romaine, Suzanne

    2016-02-01

    The compositions of diverse planetary bodies are of fundamental interest to planetary science, providing clues to the formation and evolutionary history of the target bodies and the solar system as a whole. Utilizing the X-ray fluorescence unique to each atomic element, X-ray imaging spectroscopy is a powerful diagnostic tool of the chemical and mineralogical compositions of diverse planetary bodies. Until now the mass and volume of focusing X-ray optics have been too large for resource-limited in situ missions, so near-target X-ray observations of planetary bodies have been limited to simple collimator-type X-ray instruments. We introduce a new Miniature lightweight Wolter-I focusing X-ray Optics (MiXO) using metal-ceramic hybrid X-ray mirrors based on electroformed nickel replication and plasma thermal spray processes. MiXO can enable compact, powerful imaging X-ray telescopes suitable for future planetary missions. We illustrate the need for focusing X-ray optics in observing relatively small planetary bodies such as asteroids and comet nuclei. We present a few example configurations of MiXO telescopes and demonstrate their superior performance in comparison to an alternative approach, micro-pore optics, which is being employed for the first planetary focusing X-ray telescope, the Mercury Imaging X-ray Spectrometer-T onboard Bepicolumbo. X-ray imaging spectroscopy using MiXO will open a large new discovery space in planetary science and will greatly enhance our understanding of the nature and origin of diverse planetary bodies.

  12. Applications of optical fibers and miniature photonic elements in medical diagnostics

    NASA Astrophysics Data System (ADS)

    Blaszczak, Urszula; Gilewski, Marian; Gryko, Lukasz; Zajac, Andrzej; Kukwa, Andrzej; Kukwa, Wojciech

    2014-05-01

    Construction of endoscopes which are known for decades, in particular in small devices with the diameter of few millimetres, are based on the application of fibre optic imaging bundles or bundles of fibers in the illumination systems (usually with a halogen source). Cameras - CCD and CMOS - with the sensor size of less than 5 mm emerging commercially and high power LED solutions allow to design and construct modern endoscopes characterized by many innovative properties. These constructions offer higher resolution. They are also relatively cheaper especially in the context of the integration of the majority of the functions on a single chip. Mentioned features of the CMOS sensors reduce the cycle of introducing the newly developed instruments to the market. The paper includes a description of the concept of the endoscope with a miniature camera built on the basis of CMOS detector manufactured by Omni Vision. The set of LEDs located at the operator side works as the illuminating system. Fibre optic system and the lens of the camera are used in shaping the beam illuminating the observed tissue. Furthermore, to broaden the range of applications of the endoscope, the illuminator allows to control the spectral characteristics of emitted light. The paper presents the analysis of the basic parameters of the light-and-optical system of the endoscope. The possibility of adjusting the magnifications of the lens, the field of view of the camera and its spatial resolution is discussed. Special attention was drawn to the issues related to the selection of the light sources used for the illumination in terms of energy efficiency and the possibility of providing adjusting the colour of the emitted light in order to improve the quality of the image obtained by the camera.

  13. Use of holographic optical elements in speckle metrology. Part 3: application to fracture mechanics.

    PubMed

    Shakher, C; Yadav, H L

    1991-09-01

    In this work a two-hololens imaging system has been used to measure crack-mouth opening displacement and crack-tip opening displacement to determine the stress intensity factor K(1), the crack-tip plastic zone size r(p)(*) and the rotational factor r in a beam specimen having the central edge crack subjected to three-point bending using focused plane speckle photography. Experimental results are in good agreement with theoretical predictions. Current experimental investigations establish that low-cost holographic optics can be advantageously used in speckle metrology to solve complex problems of fracture mechanics.

  14. Optical and electronic properties of conductive ternary nitrides with rare- or alkaline-earth elements

    NASA Astrophysics Data System (ADS)

    Kassavetis, S.; Hodroj, A.; Metaxa, C.; Logothetidis, S.; Pierson, J. F.; Patsalas, P.

    2016-12-01

    Conductive nitrides, such as TiN, are key engineering materials for electronics, photonics, and plasmonics; one of the essential issues for such applications is the ability of tuning the conduction electron density, the resistivity, and the electron scattering. While enhancing the conduction electron density and blueshifting the intraband absorption towards the UV were easily achieved previously, reducing the conduction electron density and redshifting the intraband absorption into the infrared are still an open issue. The latter is achieved in this work by alloying TiN by rare earth (RE = Sc, Y, La) or alkaline earth (AE = Mg, Ca) atoms in Ti substitutional positions. The produced TixRE1-xN and TixAE1-xN thin film samples were grown by a hybrid arc evaporation/sputtering process, and most of them are stable in the B1 cubic structure. Their optical properties were studied in an extensive spectral range by spectroscopic ellipsometry. The ellipsometric spectra were analyzed and quantified by the Drude-Lorentz model, which provided the conduction electron density, the electron mean free path, and the resistivity. The observed interband transitions are firmly assigned, and the optical and electrical properties of TixRE1-xN and TixAE1-xN are quantitatively correlated with their composition and crystal structure.

  15. Determination of inorganic elements in animal feeds by NIRS technology and a fibre-optic probe.

    PubMed

    González-Martín, Inmaculada; Alvarez-García, Noelia; González-Pérez, Claudio; Villaescusa-García, Virginia

    2006-05-15

    In the present work we study the use of near infra-red spectroscopy (NIRS) technology together with a remote reflectance fibre-optic probe for the analysis of the mineral composition of animal feeds. The method allows immediate control of the feeds without prior sample treatment or destruction through direct application of the fibre-optic probe on the sample. The regression method employed was modified partial least squares (MPLS). The calibration results obtained using forty samples of animal feeds allowed the determination of Fe, Mn, Ca, Na, K, P, Zn and Cu, with a standard error of prediction (SEP(C)) and a correlation coefficient (RSQ) of 0.129 and 0.859 for Fe; 0.175 and 0.816 for Mn; 5.470 and 0.927 for Ca; 2.717 and 0.862 for Na; 4.397 and 0.891 for K; 2.226 and 0.881 for P; 0.153 and 0.764 for Zn, and 0.095 and 0.918 for Cu, respectively. The robustness of the method was checked by applying it to 10 animal feeds samples of unknown mineral composition in the external validation.

  16. Optics Elements for Modeling Electrostatic Lenses and Accelerator Components: III. Electrostatic Deflectors

    SciTech Connect

    Brown, T.A.; Gillespie, G.H.

    1999-10-21

    Ion-beam optics models for simulating electrostatic prisms (deflectors) of different geometries have been developed for the computer code TRACE 3-D. TRACE 3-D is an envelope (matrix) code, which includes a linear space charge model, that was originally developed to model bunched beams in magnetic transport systems and radiofrequency (RF) accelerators. Several new optical models for a number of electrostatic lenses and accelerator columns have been developed recently that allow the code to be used for modeling beamlines and accelerators with electrostatic components. The new models include a number of options for: (1) Einzel lenses, (2) accelerator columns, (3) electrostatic prisms, and (4) electrostatic quadrupoles. A prescription for setting up the initial beam appropriate to modeling 2-D (continuous) beams has also been developed. The models for electrostatic prisms are described in this paper. The electrostatic prism model options allow the modeling of cylindrical, spherical, and toroidal electrostatic deflectors. The application of these models in the development of ion-beam transport systems is illustrated through the modeling of a spherical electrostatic analyzer as a component of the new low energy beamline at CAMS.

  17. 3-D Image-guided diffuse optical tomography using boundary element method and MPI implementation.

    PubMed

    Srinivasan, Subhadra; Ghadyani, Hamid

    2011-01-01

    Boundary elements provide an attractive method for image-guided multi-modality near infrared spectroscopy in three dimensions using only surface discretization. This method operates under the assumption that the underlying tissue contains piece-wise constant domains whose boundaries are known a priori from an alternative imaging modality such as MRI or microCT. This significantly simplifies the meshing process providing both speed-up and accuracy in the forward solution. Challenges with this method are in solving dense matrices, and working with complex heterogeneous domains. Solutions to these problems are presented here, with applications in breast cancer imaging and small - animal molecular imaging.

  18. Iterative optimization of phase-only diffractive optical elements based on a lenslet array.

    PubMed

    Arrizón, V; Testorf, M; Sinzinger, S; Jahns, J

    2000-12-01

    We describe the design of Fourier-type phase-only array generators. The numerical optimization employs the Fienup algorithm, where the parageometric design of the phase retardation profile, with the form of a lenslet array, is used as the initial guess of the optimization process. This approach provides designs with high performance that can be obtained with comparatively low computing effort. This is particularly true for elements generating large spot arrays. For symmetric reconstruction fields, the optimized phase profile typically has the same symmetry as that for the reconstruction field and can be easily unwrapped.

  19. James Webb Space Telescope (JWST) Optical Telescope Element (OTE) Pathfinder status and plans

    NASA Astrophysics Data System (ADS)

    Feinberg, Lee D.; Keski-Kuha, Ritva; Atkinson, Charlie; Booth, Andrew; Whitman, Tony

    2014-08-01

    A JWST OTE Pathfinder telescope that includes two spare primary mirror segments, a spare secondary mirror, and a large composite structure with a deployed secondary support structure is in the assembly stage and will be fully completed this year. This Pathfinder will check out key steps in the ambient mirror integration process and also be used at the Johnson Space Center (JSC) to check out the optical Ground Support Equipment (GSE) and associated procedures that will be used to test the full JWST telescope and instruments at JSC. This paper will summarize the Pathfinder integration and testing flow, the critical Ground Support Equipment it will test and the key tests planned with the Pathfinder.

  20. Optical signal processing of video surveillance for recognizing and measurement location railway infrastructure elements

    NASA Astrophysics Data System (ADS)

    Diyazitdinov, Rinat R.; Vasin, Nikolay N.

    2016-03-01

    Processing of optical signals, which are received from CCD sensors of video cameras, allows to extend the functionality of video surveillance systems. Traditional video surveillance systems are used for saving, transmitting and preprocessing of the video content from the controlled objects. Video signal processing by analytics systems allows to get more information about object's location and movement, the flow of technological processes and to measure other parameters. For example, the signal processing of video surveillance systems, installed on carriage-laboratories, are used for getting information about certain parameters of the railways. Two algorithms for video processing, allowing recognition of pedestrian crossings of the railways, as well as location measurement of the so-called "Anchor Marks" used to control the mechanical stresses of continuous welded rail track are described in this article. The algorithms are based on the principle of determining the region of interest (ROI), and then the analysis of the fragments inside this ROI.

  1. Effect of Sb addition on linear and non-linear optical properties of amorphous Ge-Se-Sn thin films

    NASA Astrophysics Data System (ADS)

    Sharma, Navjeet; Sharma, Surbhi; Sarin, Amit; Kumar, Rajesh

    2016-01-01

    Optical characterization of amorphous thin films of Ge20Sn10Se70-xSbx (x = 0, 3, 6, 9, 12, 15) has been carried out. Thin films were deposited onto pre cleaned glass substrates using thermal evaporation technique. Transmission spectra of the films were recorded, for normal incidence, in range 400-2400 nm. Refractive index of the films was calculated using the envelope method by Swanepoel. Dispersion analysis has been carried out using single effective oscillator model. Other optical constants such as absorption coefficients, extinction coefficients have also been evaluated. Tauc plots were used to evaluate the optical band gap. The refractive index has been found to be increasing while the band gap decreases with increasing Sb concentration. The observed optical behavior of the films has been explained using chemical bond approach. Cohesive energy is found to be decreasing in the present work, which reflects that bond strength decreases with the increasing content of Sb. Non-linear optical parameters (i.e. n2 and χ(3)) have been derived from linear optical parameters (i.e. n, k, Eg). Observed changes in linear and non-linear parameters have been reported in this study.

  2. Diffractive-optical-element-based glossmeter and low coherence interferometer in assessment of local surface quality of paper

    NASA Astrophysics Data System (ADS)

    Peiponen, Kai-Erik; Alarousu, Erkki; Juuti, M.; Silvennoinen, Raimo V. J.; Oksman, A.; Myllylä, Risto A.; Prykäri, Tuukka

    2006-04-01

    The surface microroughness of paper has an important role on its gloss. Unfortunately, commercial glossmeters do not provide information on the local gloss of paper. In this study a low-coherence interferometer was employed for the assessment of the average surface roughness of fine, supercalendered, and Xerox papers by means of recorded topography maps. Furthermore, the local and average gloss were measured by a diffractive-optical-element-based glossmeter. This is the first time that the measurement of the local gloss of paper has been accomplished. The information on both surface roughness and gloss, obtained by the two devices in this study, should help papermakers in their research and development of optimal paper surface quality, which is crucial to optimal ink absorption in printing.

  3. Investigation of high thermal contact conductance at low contact pressure for high-heat-load optical elements of synchrotron radiation

    NASA Astrophysics Data System (ADS)

    Takeuchi, T.; Tanaka, M.; Ohashi, H.; Goto, S.

    2013-09-01

    We measured the thermal-contact-conductance (TCC) of indirect cooling components in synchrotron radiation beamlines. To reduce the strain on the optical element, we explored conditions for insertion materials with a high TCC in region with low contact pressures of 0.1-1.0 MPa. We examined the TCC at the interface between oxygen-free copper (OFC) and insertion materials such as indium, graphite, and gold foil. The TCC depended on the hardness and thickness of the insertion material. Thin indium (20 μm thick) showed the highest TCC. Nickel and gold passivation on the OFC surface reduced the TCC to 30% of that for the bare OFC. Future work will involve exploring the passivation conditions of OFC for higher TCC is and measuring the TCC under cryogenic-cooling conditions.

  4. Research on precision grinding processing and compensation finishing experiment for mid-large- aperture square aspheric optical element

    NASA Astrophysics Data System (ADS)

    Nie, Fengming; Li, Zhanguo; Wang, Dasen; Zhang, Guangping; Guo, Chengjun; Pei, Ning; Li, Yupeng

    2014-08-01

    This paper analyzes dot-line envelope grinding principle, which is applicable to mid-large- aperture square aspheric optical element, determines the mathematical process control model based on X/Y/C three-axis aspheric grinding machine, We develop the appropriate high-precision aspheric grinding manufacturing and measurement systems software, using the plane grinding wheel to do the grinding experiments and the repeated compensation processing experiment. The experiments show that: high-precision aspheric grinding manufacturing and measurement systems software can be realized axisymmetric aspheric high-precision machining control and measurement; using compensation processing of the X/Y/C three-axis aspheric grinding machine which can effectively improve the precision PV value, surface error from the initial processing of the PV value :12 μm to the compensation processing of the PV value :3 μm .

  5. A novel method for the design of diffractive optical elements based on the Rayleigh-Sommerfeld integral

    NASA Astrophysics Data System (ADS)

    Pang, Hui; Yin, Shaoyun; Deng, Qiling; Qiu, Qi; Du, Chunlei

    2015-07-01

    The original design method for diffractive optical elements (DOEs) is limited to cases of small-angle diffraction due to the Fresnel or Fraunhofer diffraction integral. In this paper, we propose a new method based on the Rayleigh-Sommerfeld diffraction integral, which does not have this limit. In this method, the target intensity distribution is first modified via coordinate transformation and intensity adjustment. Then, the modified Gerchberg-Saxton algorithm is used to achieve the phase distribution of the DOE. To verify this method, simulations and experiments are performed. The results show that the original method is effective only when the full diffraction angle of the DOE is below 25°. Conversely, this method can achieve the target with both small and large diffraction angles.

  6. Measured elemental carbon by thermo-optical transmittance analysis in water-soluble extracts from diesel exhaust, woodsmoke, and ambient particulate samples.

    PubMed

    Wallén, Anna; Lidén, Göran; Hansson, Hans-Christen

    2010-01-01

    Elemental carbon has been proposed as a marker of diesel particulate matter. The objective of this study was to investigate if water-soluble carbonaceous compounds could be responsible for positive bias of elemental carbon using NIOSH Method 5040 with a thermo-optical carbon transmittance analyzer. Filter samples from eight different aerosol environments were used: pure diesel exhaust fume with a high content of elemental carbon, pure diesel exhaust fume with a low content of elemental carbon, pure biodiesel exhaust fume, pure woodsmoke, an urban road tunnel, an urban street canyon, an urban background site, and residential woodburning in an urban area. Part of each filter sample was analyzed directly with a thermo-optical carbon analyzer, and another part was extracted with water. This water-soluble extract was filtered to remove particles, spiked onto filter punches, and analyzed with a thermo-optical transmittance carbon analyzer. The ratio of elemental carbon in the water-soluble extract to the particulate sample measurement was 18, 12, and 7%, respectively, for the samples of pure woodsmoke, residential woodburning, and urban background. Samples with diesel particulate matter and ambient samples with motor exhaust detected no elemental carbon in the water-soluble extract. Since no particles were present in the filtered water-soluble extract, part of the water-soluble organic carbon species, existing or created during analysis, are misclassified as elemental carbon with this analysis. The conclusion is that in measuring elemental carbon in particulate aerosol samples with thermo-optical transmittance analysis, woodsmoke, and biomass combustion samples show a positive bias of elemental carbon. The water-soluble EC could be used as a simple method to indicate other sources, such as wood or other biomass combustion aerosol particles.

  7. Simultaneous determination of macronutrients, micronutrients and trace elements in mineral fertilizers by inductively coupled plasma optical emission spectrometry

    NASA Astrophysics Data System (ADS)

    de Oliveira Souza, Sidnei; da Costa, Silvânio Silvério Lopes; Santos, Dayane Melo; dos Santos Pinto, Jéssica; Garcia, Carlos Alexandre Borges; Alves, José do Patrocínio Hora; Araujo, Rennan Geovanny Oliveira

    2014-06-01

    An analytical method for simultaneous determination of macronutrients (Ca, Mg, Na and P), micronutrients (Cu, Fe, Mn and Zn) and trace elements (Al, As, Cd, Pb and V) in mineral fertilizers was optimized. Two-level full factorial design was applied to evaluate the optimal proportions of reagents used in the sample digestion on hot plate. A Doehlert design for two variables was used to evaluate the operating conditions of the inductively coupled plasma optical emission spectrometer in order to accomplish the simultaneous determination of the analyte concentrations. The limits of quantification (LOQs) ranged from 2.0 mg kg- 1 for Mn to 77.3 mg kg- 1 for P. The accuracy and precision of the proposed method were evaluated by analysis of standard reference materials (SRMs) of Western phosphate rock (NIST 694), Florida phosphate rock (NIST 120C) and Trace elements in multi-nutrient fertilizer (NIST 695), considered to be adequate for simultaneous determination. Twenty-one samples of mineral fertilizers collected in Sergipe State, Brazil, were analyzed. For all samples, the As, Ca, Cd and Pb concentrations were below the LOQ values of the analytical method. For As, Cd and Pb the obtained LOQ values were below the maximum limit allowed by the Brazilian Ministry of Agriculture, Livestock and Food Supply (Ministério da Agricultura, Pecuária e Abastecimento - MAPA). The optimized method presented good accuracy and was effectively applied to quantitative simultaneous determination of the analytes in mineral fertilizers by inductively coupled plasma optical emission spectrometry (ICP OES).

  8. Effect of glycine addition on the structural, thermal, optical, mechanical and electrical properties of Sr (HCOO)2·2H2O crystals

    NASA Astrophysics Data System (ADS)

    Muthupoongodi, S.; Theodore David Manickam, S.; Mahadevan, C. K.; Angel Mary Greena, J.; Balakumar, S.; Sahaya Shajan, X.

    2015-10-01

    Pure and glycine doped strontium formate dihydrate (SFD) single crystals were grown by the free evaporation method to understand the effect of glycine addition on the structural, thermal, optical, mechanical and electrical properties of SFD crystal. The grown crystals were characterized by carrying out powder X-ray diffraction, high resolution X-ray diffraction, Fourier transform infrared spectral, Raman spectral, UV-vis-NIR spectral, thermogravimetric (TG/DTA), second harmonic generation (SHG), microhardness and DC electrical conductivity measurements. Results obtained in the present study indicate improvement in crystalline perfection, optical transmittance, and SHG efficiency, and change in microhardness, and DC electrical conductivity on doping SFD with glycine. In addition, a large size (~1.9 cm length, ~1.2 cm breath and ~0.6 cm height) SFD crystal with good optical quality could be grown successfully by the seeded free evaporation method.

  9. Visual and Optical Performances of Multifocal Intraocular Lenses with Three Different Near Additions: 6-Month Follow-Up

    PubMed Central

    Wang, Mengmeng; Corpuz, Christine Carole C; Fujiwara, Megumi; Tomita, Minoru

    2015-01-01

    Purpose : To compare the visual and optical outcomes of four multifocal intraocular lenses (IOLs) with three different near additions of +3.00 diopters (D), +3.75 D and +4.00 D. Methods : In this prospective study, 133 eyes of 88 patients were implanted with one of the following IOLs: AcrySof® ReSTOR® SN6AD1 (+3.00 D) for Group A, AcrivaUD Reviol BB MF 613 or BB MFM 611 (+3.75 D) for Group B, and AcrySof® ReSTOR® SN6AD3 (+4.00 D) for Group C. The visual acuity, refraction, intraocular pressure, tomography and corneal endothelial cell density (ECD) were compared between the three groups preoperatively and at 6 month postoperatively. Defocus curve, contrast sensitivity and higher order aberrations (HOAs) at 6 month postoperative visit were measured and compared. Results : There were no statistically significant differences in distance visual acuity, refraction, intraocular pressure or ECD among the three groups after 6 months (P > 0.05). The photopic contrast sensitivity in Group C was statistically better than in Group A (P < 0.05). The scotopic ocular aberration in Group B was statistically greater compared to that in Group A (P < 0.05). The highest near-visual peaks were -0.06 logMAR at a -2.50 D (40 cm) in Group A, -0.07 logMAR at -3.00D (33 cm) in Group B, and -0.06 logMAR at -3.50 D (29 cm) in Group C. Statistically significant differences in near and intermediate visual acuities were observed among the three groups at -2.00 D (50 cm), -2.50 D (40 cm), -3.50 D (29 cm) and -4.00 D (25 cm) (P < 0.01). Conclusion : AcrySof® ReSTOR® SN6AD1 IOLs (+3.00 D) and SN6AD3 (+4.00 D) IOLs provided the best intermediate and near vision, respectively. Both intermediate and near vision were comparatively better in the eyes with AcrivaUD Reviol BB MFM 611 IOLs or BB MF 613 IOLs (+3.75 D). PMID:25674189

  10. An investigation of the optics of a 5-element electrostatic lens for use with a high brightness ion source

    NASA Astrophysics Data System (ADS)

    Colman, R. A.; Legge, G. J. F.

    1994-03-01

    The optics of a configuration consisting of a biased ion source exit canal, followed by a four-electrode electrostatic lens is investigated. This effectively operates as a five-electrode electrostatic lens (although two electrodes are in fact wired at the same potential). This lens displays three degrees of freedom in achieving a required beam focus. In particular, this lens is investigated to determine its optimal configuration for the present, low voltage ion source and its suitability for use with a high voltage field ionization ion source. The finite element method is used to calculate the electrostatic field in the lens, and optical properties are extracted from ray tracing. A full range of "accelerating" and "decelerating" focusing modes are analysed with a range of final to initial voltage ratios of between 1 and 16, and with and without a beam crossover inside the lens. It is found that aberrations are lowest for large initial acceleration, and with no beam crossover, with the optimal aberrations being relatively insensitive to the final electrode voltage. Calculations suggest, however, that the introduction of a high voltage field ionization source would almost certainly preclude the use of the optimal lens configuration in practice.

  11. Mechanical performance of physical-contact, multi-fiber optical connectors: Finite element analysis and semi-analytical model

    NASA Astrophysics Data System (ADS)

    Marin, Esteban B.; Tran, Hieu V.; Kobyakov, Andrey

    2016-07-01

    Three-dimensional finite element analysis of physical-contact, multi-fiber optical connector was used to characterize fiber-to-fiber contact and support the development and validation of a semi-analytical model (SAM) for the contact force. This contact behavior is determined by the elastic deformation of the system components (ferrule, fibers, and bonding adhesive) and the classical Hertzian contact at the fiber tips - effects that ultimately define the axial compliance of the system. Two 3-D finite element models for a 12-fiber connector are constructed to study the contact of two connectors, and the specific numerical simulations are carried out to generate input data to SAM, confirm the main assumptions made in its development, and numerically validate the predictions for the contact force. These simulations mainly consider non-uniform fiber height profiles and different end-face fiber tip geometries characterized by their radius of curvature. The numerically validated SAM is then used to study some performance aspects of multi-fiber connectors as related to the required contact force, namely, finding fiber height profiles that require minimum contact force and evaluating the throughput of polishing processes assuming a target contact force. Predictions are supported by Monte Carlo simulations and associated with current profile geometry metrics.

  12. In vivo X-ray elemental imaging of single cell model organisms manipulated by laser-based optical tweezers

    PubMed Central

    Vergucht, Eva; Brans, Toon; Beunis, Filip; Garrevoet, Jan; De Rijcke, Maarten; Bauters, Stephen; Deruytter, David; Vandegehuchte, Michiel; Van Nieuwenhove, Ine; Janssen, Colin; Burghammer, Manfred; Vincze, Laszlo

    2015-01-01

    We report on a radically new elemental imaging approach for the analysis of biological model organisms and single cells in their natural, in vivo state. The methodology combines optical tweezers (OT) technology for non-contact, laser-based sample manipulation with synchrotron radiation confocal X-ray fluorescence (XRF) microimaging for the first time. The main objective of this work is to establish a new method for in vivo elemental imaging in a two-dimensional (2D) projection mode in free-standing biological microorganisms or single cells, present in their aqueous environment. Using the model organism Scrippsiella trochoidea, a first proof of principle experiment at beamline ID13 of the European Synchrotron Radiation Facility (ESRF) demonstrates the feasibility of the OT XRF methodology, which is applied to study mixture toxicity of Cu-Ni and Cu-Zn as a result of elevated exposure. We expect that the new OT XRF methodology will significantly contribute to the new trend of investigating microorganisms at the cellular level with added in vivo capability. PMID:25762511

  13. Real-time processor based on GPU for on-line performance evaluation of the 127-element adaptive optics system

    NASA Astrophysics Data System (ADS)

    Zhou, Han; Zhou, Lu-chun

    2013-08-01

    In this paper, a real-time on-line performance evaluation processor based on graphic processing unit (GPU) for adaptive optics (AO) system is presented, aiming to monitor the 127-element AO system during its close-loop work by quantifying its correction results, which can provide reference to improve the performance of the system. Since there is a contradiction between the heavy computation burden and the real-time processing requirement, we modified operations and algorithms to fit the CPU-GPU heterogeneous environment, in which GPU is used to handle the complex computation but simple logicality, and CPU is assigned to undertake data transportation between internal storage and video memory,as well as some small-scale computations. In the real-time processor, performance parameters to be computed include peak-valley (PV) and root-mean-square (RMS) of near-field wavefront phase, point spread function (PSF), full width half maximum (FWHM) of far-field image,modulation transfer function (MTF) and Strehl ratio (SR). And the inputs are residual slopes obtained from Hartmann wavefront sensor of 127-element AO system. By computation 4096 frames of parameters, the average rate by single precision is 4.11ms/frame.

  14. Elemental analysis of glass by laser ablation inductively coupled plasma optical emission spectrometry (LA-ICP-OES).

    PubMed

    Schenk, Emily R; Almirall, José R

    2012-04-10

    The elemental analysis of glass evidence has been established as a powerful discrimination tool for forensic analysts. Laser ablation inductively coupled plasma optical emission spectrometry (LA-ICP-OES) has been compared to laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and energy dispersive micro X-ray fluorescence spectroscopy (μXRF/EDS) as competing instrumentation for the elemental analysis of glass. The development of a method for the forensic analysis of glass coupling laser ablation to ICP-OES is presented for the first time. LA-ICP-OES has demonstrated comparable analytical performance to LA-ICP-MS based on the use of the element menu, Al (Al I 396.15 nm), Ba (Ba II 455.40 nm), Ca (Ca II 315.88 nm), Fe (Fe II 238.20 nm), Li (Li I 670.78 nm), Mg (Mg I 285.21 nm), Sr (Sr II 407.77 nm), Ti (Ti II 368.51 nm), and Zr (Zr II 343.82 nm). The relevant figures of merit, such as precision, accuracy and sensitivity, are presented and compared to LA-ICP-MS. A set of 41 glass samples was used to assess the discrimination power of the LA-ICP-OES method in comparison to other elemental analysis techniques. This sample set consisted of several vehicle glass samples that originated from the same source (inside and outside windshield panes) and several glass samples that originated from different vehicles. Different match criteria were used and compared to determine the potential for Type I and Type II errors. It was determined that broader match criteria is more applicable to the forensic comparison of glass analysis because it can reduce the affect that micro-heterogeneity inherent in the glass fragments and a less than ideal sampling strategy can have on the interpretation of the results. Based on the test set reported here, a plus or minus four standard deviation (± 4s) match criterion yielded the lowest possibility of Type I and Type II errors. The developed LA-ICP-OES method has been shown to perform similarly to LA-ICP-MS in the

  15. Neutron focusing using capillary optics and its applications to elemental analysis

    SciTech Connect

    Chen-Mayer, H. H.; Mildner, D. F. R.; Lamaze, G. P.; Paul, R. L.; Lindstrom, R. M.

    1999-06-10

    Capillary optics (Kumakhov lenses) have been characterized and tested at two cold neutron beam facilities at the NIST reactor: the Neutron Depth Profiling (NDP) and the Prompt Gamma Activation Analysis (PGAA) spectrometers. Lenses of both multifiber and monolithic types focus cold neutron beams from guides of cm transverse dimensions onto a sub-mm spot size with higher current densities at the expense of the angular resolution, which is acceptable for applications employing neutron absorption. These lenses can improve the sensitivity and detection limits for NDP and PGAA measurements on small samples, and enable sample scanning to study spatial non-uniformity or to perform compositional mapping. A summary of the neutron focusing effort is given, with examples of a multifiber lens with on-axis focusing, a bender-focuser with off-axis focusing, and a monolithic lens with a more compact size. Preliminary results and existing problems in applying these lenses to NDP and PGAA are presented, and current and future directions are discussed.

  16. Neutron focusing using capillary optics and its applications to elemental analysis

    NASA Astrophysics Data System (ADS)

    Chen-Mayer, H. H.; Mildner, D. F. R.; Lamaze, G. P.; Paul, R. L.; Lindstrom, R. M.

    1999-06-01

    Capillary optics (Kumakhov lenses) have been characterized and tested at two cold neutron beam facilities at the NIST reactor: the Neutron Depth Profiling (NDP) and the Prompt Gamma Activation Analysis (PGAA) spectrometers. Lenses of both multifiber and monolithic types focus cold neutron beams from guides of cm transverse dimensions onto a sub-mm spot size with higher current densities at the expense of the angular resolution, which is acceptable for applications employing neutron absorption. These lenses can improve the sensitivity and detection limits for NDP and PGAA measurements on small samples, and enable sample scanning to study spatial non-uniformity or to perform compositional mapping. A summary of the neutron focusing effort is given, with examples of a multifiber lens with on-axis focusing, a bender-focuser with off-axis focusing, and a monolithic lens with a more compact size. Preliminary results and existing problems in applying these lenses to NDP and PGAA are presented, and current and future directions are discussed.

  17. An integrated optical CO2 sensor. Phase 0: Design and fabrication of critical elements

    NASA Technical Reports Server (NTRS)

    Murphy, Michael C.; Kelly, Kevin W.; Li, B. Q.; Ma, EN; Wang, Wanjun; Vladimirsky, Yuli; Vladimirsky, Olga

    1994-01-01

    Significant progress has been made toward all of the goals for the first phase of the project short of actual fabrication of a light path. Two alternative approaches to fabricating gold mirrors using the basic LIGA process were developed, one using electroplated solid gold mirrors and the second using gold plated over a nickel base. A new method of fabrication, the transfer mask process, was developed and demonstrated. Analysis of the projected surface roughness and beam divergence effects was completed. With gold surface with low surface roughness scattering losses are expected to be insignificant. Beam divergence due to diffraction will require a modification of the original design, but should be eliminated by fabricating mirrors 1000 mu m in height by 1000 mu m in width and using a source with an initial beam radius greater than 300 mu m. This may eliminate any need for focusing optics. Since the modified design does not affect the mask layout, ordering of the mask and fabrication of the test structures can begin immediately at the start of Phase 1.

  18. Elemental composition and optical properties reveal changes in dissolved organic matter along a permafrost thaw chronosequence in a subarctic peatland

    NASA Astrophysics Data System (ADS)

    Hodgkins, Suzanne B.; Tfaily, Malak M.; Podgorski, David C.; McCalley, Carmody K.; Saleska, Scott R.; Crill, Patrick M.; Rich, Virginia I.; Chanton, Jeffrey P.; Cooper, William T.

    2016-08-01

    The fate of carbon stored in permafrost-zone peatlands represents a significant uncertainty in global climate modeling. Given that the breakdown of dissolved organic matter (DOM) is often a major pathway for decomposition in peatlands, knowledge of DOM reactivity under different permafrost regimes is critical for determining future climate feedbacks. To explore the effects of permafrost thaw and resultant plant succession on DOM reactivity, we used a combination of Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), UV/Vis absorbance, and excitation-emission matrix spectroscopy (EEMS) to examine the DOM elemental composition and optical properties of 27 pore water samples gathered from various sites along a permafrost thaw sequence in Stordalen Mire, a thawing subarctic peatland in northern Sweden. The presence of dense Sphagnum moss, a feature that is dominant in the intermediate thaw stages, appeared to be the main driver of variation in DOM elemental composition and optical properties at Stordalen. Specifically, DOM from sites with Sphagnum had greater aromaticity, higher average molecular weights, and greater O/C, consistent with a higher abundance of phenolic compounds that likely inhibit decomposition. These compounds are released by Sphagnum and may accumulate due to inhibition of phenol oxidase activity by the acidic pH at these sites. In contrast, sites without Sphagnum, specifically fully-thawed rich fens, had more saturated, more reduced compounds, which were high in N and S. Optical properties at rich fens indicated the presence of microbially-derived DOM, consistent with the higher decomposition rates previously measured at these sites. These results indicate that Sphagnum acts as an inhibitor of rapid decomposition and CH4 release in thawing subarctic peatlands, consistent with lower rates of CO2 and CH4 production previously observed at these sites. However, this inhibitory effect may disappear if Sphagnum-dominated bogs

  19. Elemental composition and optical properties reveal changes in dissolved organic matter along a permafrost thaw chronosequence in a subarctic peatland

    SciTech Connect

    Hodgkins, Suzanne B.; Tfaily, Malak M.; Podgorski, David C.; McCalley, Carmody K.; Saleska, Scott R.; Crill, Patrick M.; Rich, Virginia I.; Chanton, Jeffrey P.; Cooper, William T.

    2016-08-01

    The fate of carbon stored in permafrost-zone peatlands represents a significant uncertainty in global climate modeling. Given that the breakdown of dissolved organic matter (DOM) is often a major pathway for decomposition in peatlands, knowledge of DOM reactivity under different permafrost regimes is critical for determining future climate feedbacks. To explore the effects of permafrost thaw and resultant plant succession on DOM reactivity, we used a combination of Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), UV/Vis absorbance, and excitation-emission matrix spectroscopy (EEMS) to examine the DOM elemental composition and optical properties of 27 pore water samples gathered from various sites along a permafrost thaw sequence in Stordalen Mire, a thawing subarctic peatland in northern Sweden. The presence of dense Sphagnum moss, a feature that is dominant in the intermediate thaw stages, appeared to be the main driver of variation in DOM elemental composition and optical properties at Stordalen. Specifically, DOM from sites with Sphagnum had greater aromaticity, higher average molecular weights, and greater O/C, consistent with a higher abundance of phenolic compounds that likely inhibit decomposition. These compounds are released by Sphagnum and may accumulate due to inhibition of phenol oxidase activity by the acidic pH at these sites. In contrast, sites without Sphagnum, specifically fully-thawed rich fens, had more saturated, more reduced compounds, which were high in N and S. Optical properties at rich fens were indicated the presence of microbially-derived DOM, consistent with the higher decomposition rates previously measured at these sites. These results indicate that Sphagnum acts as an inhibitor of rapid decomposition and CH4 release in thawing subarctic peatlands, consistent with lower rates of CO2 and CH4 production previously observed at these sites. However, this inhibitory effect may disappear if Sphagnumdominated bogs

  20. Determination of rare earth and concomitant elements in magnesium alloys by inductively coupled plasma optical emission spectrometry.

    PubMed

    Fariñas, Juan C; Rucandio, Isabel; Pomares-Alfonso, Mario S; Villanueva-Tagle, Margarita E; Larrea, María T

    2016-07-01

    An Inductively Coupled Plasma Optical Emission Spectrometry method for simultaneous determination of Al, Ca, Cu, Fe, In, Mn, Ni, Si, Sr, Y, Zn, Zr and rare earth elements (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) in magnesium alloys, including the new rare earth elements-alloyed magnesium, has been developed. Robust conditions have been established as nebulizer argon flow rate of 0.5mLmin(-1) and RF incident power of 1500W, in which matrix effects were significantly reduced around 10%. Three acid digestion procedures were performed at 110°C in closed PFA vessels heated in an oven, in closed TFM vessels heated in a microwave furnace, and in open polypropylene tubes with reflux caps heated in a graphite block. The three digestion procedures are suitable to put into solution the magnesium alloys samples. From the most sensitive lines, one analytical line with lack or low spectral interferences has been selected for each element. Mg, Rh and Sc have been studied as internal standards. Among them, Rh was selected as the best one by using Rh I 343.488nm and Rh II 249.078nm lines as a function of the analytical lines. The trueness and precision have been established by using the Certified Reference Material BCS 316, as well as by means of recovery studies. Quantification limits were between 0.1 and 9mgkg(-1) for Lu and Pr, respectively, in a 2gL(-1) magnesium matrix solution. The method developed has been applied to the commercial alloys AM60, AZ80, ZK30, AJ62, WE54 and AE44.

  1. Finite element modeling of concentrating solar collectors for evauation of gravity loads, bending, and optical characterization.

    SciTech Connect

    Christian, Joshua M.; Ho, Clifford Kuofei

    2010-04-01

    Understanding the effects of gravity and wind loads on concentrating solar power (CSP) collectors is critical for performance calculations and developing more accurate alignment procedures and techniques. This paper presents a rigorous finite-element model of a parabolic trough collector that is used to determine the impact of gravity loads on bending and displacements of the mirror facets and support structure. The geometry of the LUZ LS-2 parabolic trough collector was modeled using SolidWorks, and gravity-induced loading and displacements were simulated in SolidWorks Simulation. The model of the trough collector was evaluated in two positions: the 90{sup o} position (mirrors facing upward) and the 0{sup o} position (mirrors facing horizontally). The slope errors of the mirror facet reflective surfaces were found by evaluating simulated angular displacements of node-connected segments along the mirror surface. The ideal (undeformed) shape of the mirror was compared to the shape of the deformed mirror after gravity loading. Also, slope errors were obtained by comparing the deformed shapes between the 90{sup o} and 0{sup o} positions. The slope errors resulting from comparison between the deformed vs. undeformed shape were as high as {approx}2 mrad, depending on the location of the mirror facet on the collector. The slope errors resulting from a change in orientation of the trough from the 90{sup o} position to the 0{sup o} position with gravity loading were as high as {approx}3 mrad, depending on the location of the facet.

  2. Experimental demonstration of hybrid imaging for miniaturization of an optical zoom lens with a single moving element.

    PubMed

    Demenikov, Mads; Findlay, Ewan; Harvey, Andrew R

    2011-03-15

    We experimentally demonstrate a miniaturized zoom lens with a single moving element based on the concepts and analysis described in Opt. Express 17, 6118 (2009). We show that the implementation of either a cubic or a generalized cubic phase-modulation function makes miniaturization possible in addition to providing extended-depth-of-field imaging. We present recovered images for zoom lenses employing both phase-modulation functions and conclude that the generalized-cubic-phase function yields higher image quality without the artifacts present for the pure-cubic-phase function.

  3. Influence of ternary addition of transition elements (Cr, Si and Mn) on the microstructure and magnetic properties of nano-structured CuCo alloy

    NASA Astrophysics Data System (ADS)

    Mondal, B. N.; Chabri, S.; Basumallick, A.; Chattopadhyay, P. P.

    2012-09-01

    The current state of studies presents the effect of ternary addition of transition elements such as Mn, Cr and Si (10 wt%) on the mechanically driven non-equilibrium solubility of 40 wt% Co containing Cu-Co alloy. X-ray powder diffraction analysis indicates that addition of Mn has been found to be the most effective in enhancing the solubility and formation of a complete solid solution between Co and Cu in a short duration (30 h) of ball milling. The microstructure of the ball milled CuCoMn alloy was found to be stable after the isothermal annealing up to a temperature of 450 °C for 1 h. The magnetic properties such as magnetic saturation, coercivity and remanence of ball milled CuCo alloy in the presence of Mn significantly altered after annealing in the temperature range 350-650 °C for 1 h. The best combination of magnetic properties of CuCoMn alloy has been found after annealing at 550 °C for 1 h.

  4. Clues for a standardised thermal-optical protocol for the assessment of organic and elemental carbon within ambient air particulate matter

    NASA Astrophysics Data System (ADS)

    Chiappini, L.; Verlhac, S.; Aujay, R.; Maenhaut, W.; Putaud, J. P.; Sciare, J.; Jaffrezo, J. L.; Liousse, C.; Galy-Lacaux, C.; Alleman, L. Y.; Panteliadis, P.; Leoz, E.; Favez, O.

    2014-06-01

    Along with some research networking programmes, the European Directive 2008/50/CE requires chemical speciation of fine aerosol (PM2.5), including elemental (EC) and organic carbon (OC), at a few rural sites in European countries. Meanwhile, the thermal-optical technique is considered by the European and US networking agencies and normalisation bodies as a reference method to quantify EC-OC collected on filters. Although commonly used for many years, this technique still suffers from a lack of information on the comparability of the different analytical protocols (temperature protocols, type of optical correction) currently applied in the laboratories. To better evaluate the EC-OC data set quality and related uncertainties, the French National Reference Laboratory for Ambient Air Quality Monitoring (LCSQA) organised an EC-OC comparison exercise for French laboratories using different thermal-optical methods (five laboratories only). While there is good agreement on total carbon (TC) measurements among all participants, some differences can be observed on the EC / TC ratio, even among laboratories using the same thermal protocol. These results led to further tests on the influence of the optical correction: results obtained from different European laboratories confirmed that there were higher differences between OCTOT and OCTOR measured with NIOSH 5040 in comparison to EUSAAR-2. Also, striking differences between ECTOT / ECTOR ratios can be observed when comparing results obtained for rural and urban samples, with ECTOT being 50% lower than ECTOR at rural sites whereas it is only 20% lower at urban sites. The PM chemical composition could explain these differences but the way it influences the EC-OC measurement is not clear and needs further investigation. Meanwhile, some additional tests seem to indicate an influence of oven soiling on the EC-OC measurement data quality. This highlights the necessity to follow the laser signal decrease with time and its impact on

  5. The influence of Citrosept addition to drinking water and Scutellaria baicalensis root extract on the content of selected mineral elements in the blood plasma of turkey hens.

    PubMed

    Rusinek-Prystupa, Elżbieta; Lechowski, Jerzy; Zukiewicz-Sobczak, Wioletta; Sobczak, Paweł; Zawiślak, Kazimierz

    2014-01-01

    The aim of this research work was to indicate the influence of Citrosept preparation and Scutellaria baicalensis root extract, administered per os to growing turkey hens in 3 different dosages, on the content of selected mineral elements in blood plasma of slaughter turkey hens. An attempt was also made to specify the most effective dosage of the applied preparations with the highest efficiency as regards increased levels of examined macro- and microelements in the birds' blood. The research experiment was conducted on 315 turkey hens randomly divided into seven groups, each consisting of 45 turkey hens. Group K constituted the control group without experimental additions of the above-mentioned preparations. When it comes to turkey hens which belonged to groups II-IV, Citrosept preparation was instilled to water in the following dosages: Group II - 0.011 ml/kg of bm; Group III - 0.021 ml/kg of bm; Group IV - 0.042 ml/kg bm. For birds which belonged to groups V-VII preparation, which was Scutellaria baicalensis root extract, was instilled to water in the following dosages: Group V - 0.009 ml/kg of bm; Group VI - 0.018 ml/kg of bm, Group VII - 0.036 ml/kg bm. In the examined plant extracts and blood plasma of the birds the levels of Na, K, Ca, Mg, Cu, Zn, and Fe were identified. The use of examined extracts influenced the changes in the levels of all tested elements in slaughter turkey hens' blood plasma. An upward tendency was recorded which regarded the level of calcium and magnesium, and a downward tendency of sodium, potassium, copper, zinc, and iron in relation to the results achieved in the control group.

  6. Demonstration of frequency control and CW diode laser injection control of a titanium-doped sapphire ring laser with no internal optical elements

    NASA Technical Reports Server (NTRS)

    Bair, Clayton H.; Brockman, Philip; Hess, Robert V.; Modlin, Edward A.

    1988-01-01

    Theoretical and experimental frequency narrowing studies of a Ti:sapphire ring laser with no intracavity optical elements are reported. Frequency narrowing has been achieved using a birefringent filter between a partially reflecting reverse wave suppressor mirror and the ring cavity output mirror. Results of CW diode laser injection seeding are reported.

  7. Influencing the arc and the mechanical properties of the weld metal in GMA-welding processes by additive elements on the wire electrode surface

    NASA Astrophysics Data System (ADS)

    Wesling, V.; Schram, A.; Müller, T.; Treutler, K.

    2016-03-01

    Under the premise of an increasing scarcity of raw materials and increasing demands on construction materials, the mechanical properties of steels and its joints are gaining highly important. In particular high- and highest-strength steels are getting in the focus of the research and the manufacturing industry. To the same extent, the requirements for filler metals are increasing as well. At present, these low-alloy materials are protected by a copper coating (<1μm) against corrosion. In addition, the coating realizes a good ohmic contact and good sliding properties between the welding machine and the wire during the welding process. By exchanging the copper with other elements it should be possible to change the mechanical properties of the weld metal and the arc stability during gas metal arc welding processes and keep the basic functions of the coating nearly untouched. On a laboratory scale solid wire electrodes with coatings of various elements and compounds such as titanium oxide were made and processed with a Gas Metal Arc Welding process. During the processing a different process behavior between the wire electrodes, coated and original, could be observed. The influences ranges from greater/shorter arc-length over increasing/decreasing droplets to larger/smaller arc foot point. Furthermore, the weld metal of the coated electrodes has significantly different mechanical and technological characteristics as the weld metal from the copper coated ground wire. The yield strength and tensile strength can be increased by up to 50%. In addition, the chemical composition of the weld metal was influenced by the application of coatings with layer thicknesses to 15 microns in the lower percentage range (up to about 3%). Another effect of the coating is a modified penetration. The normally occurring “argon finger” can be suppressed or enhanced by the choice of the coating. With the help of the presented studies it will be shown that Gas Metal Arc Welding processes

  8. Active optical zoom system

    DOEpatents

    Wick, David V.

    2005-12-20

    An active optical zoom system changes the magnification (or effective focal length) of an optical imaging system by utilizing two or more active optics in a conventional optical system. The system can create relatively large changes in system magnification with very small changes in the focal lengths of individual active elements by leveraging the optical power of the conventional optical elements (e.g., passive lenses and mirrors) surrounding the active optics. The active optics serve primarily as variable focal-length lenses or mirrors, although adding other aberrations enables increased utility. The active optics can either be LC SLMs, used in a transmissive optical zoom system, or DMs, used in a reflective optical zoom system. By appropriately designing the optical system, the variable focal-length lenses or mirrors can provide the flexibility necessary to change the overall system focal length (i.e., effective focal length), and therefore magnification, that is normally accomplished with mechanical motion in conventional zoom lenses. The active optics can provide additional flexibility by allowing magnification to occur anywhere within the FOV of the system, not just on-axis as in a conventional system.

  9. Simultaneous self-starting additive pulse mode-locking and second harmonic generation of an Nd:YAG laser using self-organised germanosilicate optical fibres

    NASA Astrophysics Data System (ADS)

    Bernardin, J. P.; Lawandy, N. M.

    1991-08-01

    The simultaneous operation of self-starting additive pulse mode-locking and optical fiber second harmonic generation of an Nd:YAG laser resulting in picosecond radiation at 1.06 mm and 532 nm was demonstrated. The IR pulses were measured to be 5 ps in duration, and the green pulses are expected to be approximately 3.5 ps due to the nonlinear interaction. Effects of self-modulation and cross-phase modulation on the conversion efficiency are discussed.

  10. Grain refinement in heavy rare earth element-free sintered Nd–Fe–B magnets by addition of a small amount of molybdenum

    SciTech Connect

    Kim, Jin Woo; Lee, Won Suk; Byun, Jong Min; Kim, Young Do; Kim, Se Hoon

    2015-05-07

    We employed a modified refractory-metal-addition method to achieve higher coercivity and remanence in heavy rare earth element (HREE)-free Nd–Fe–B sintered magnets. This process involved inducing the formation of a homogeneous secondary phase at the grain boundaries during sintering, making it possible to control the intergrain diffusion by adding small amounts of Mo, a refractory metal. To control the microstructure of the secondary phase effectively, a metal organic compound of the refractory metal was coated on the surfaces of the particles of an HREE-free Nd–Fe–B powder. The average grain size after this process was 5.60 μm, which was approximately 1.8 μm smaller than that of the HREE-free sintered Nd–Fe–B magnets (7.4 μm). The coercivity of the magnets prepared through this process could be increased from 11.88 kOe to 13.91 kOe without decreasing their remanence.

  11. Additive Promotion of Viral Internal Ribosome Entry Site-Mediated Translation by Far Upstream Element-Binding Protein 1 and an Enterovirus 71-Induced Cleavage Product

    PubMed Central

    Hung, Chuan-Tien; Kung, Yu-An; Li, Mei-Ling; Lee, Kuo-Ming; Liu, Shih-Tung; Shih, Shin-Ru

    2016-01-01

    The 5' untranslated region (5' UTR) of the enterovirus 71 (EV71) RNA genome contains an internal ribosome entry site (IRES) that is indispensable for viral protein translation. Due to the limited coding capacity of their RNA genomes, EV71 and other picornaviruses typically recruit host factors, known as IRES trans-acting factors (ITAFs), to mediate IRES-dependent translation. Here, we show that EV71 viral proteinase 2A is capable of cleaving far upstream element-binding protein 1 (FBP1), a positive ITAF that directly binds to the EV71 5' UTR linker region to promote viral IRES-driven translation. The cleavage occurs at the Gly-371 residue of FBP1 during the EV71 infection process, and this generates a functional cleavage product, FBP11-371. Interestingly, the cleavage product acts to promote viral IRES activity. Footprinting analysis and gel mobility shift assay results showed that FBP11-371 similarly binds to the EV71 5' UTR linker region, but at a different site from full-length FBP1; moreover, FBP1 and FBP11-371 were found to act additively to promote IRES-mediated translation and virus yield. Our findings expand the current understanding of virus-host interactions with regard to viral recruitment and modulation of ITAFs, and provide new insights into translational control during viral infection. PMID:27780225

  12. Effects of Al Content and Addition of Third Element on Fabrication of Ti-Al Intermetallic Coatings by Heat Treatment of Warm-Sprayed Precursors

    NASA Astrophysics Data System (ADS)

    Sienkiewicz, J.; Kuroda, S.; Minagawa, K.; Murakami, H.; Araki, H.; Kurzydłowski, K. J.

    2015-06-01

    Four powder mixtures of titanium and aluminum with 50:50, 40:60, 30:70, and 20:80 atomic ratios were used as feedstock for Warm Spray process to produce composite coatings. A two-stage heat treatment at 600 and 1000 °C was applied to the deposits in order to obtain titanium aluminide intermetallic phases. The microstructure, chemical, and phase composition of the as-deposited and heat-treated coatings were investigated using SEM, EDS, and XRD. It was found that the Al content affects on the thickness expansion of the heat-treated Ti-Al coatings significantly and also has a major influence on the porosity development, which is caused by the Kirkendall effect. The effects of adding a third element Si and heat treatment with pressure to produce denser Ti-Al intermetallic coating were also examined. The investigated hot-pressed coatings with addition of Si exhibited much denser microstructure and contained Ti-Al intermetallic phases with titanium silicide precipitates.

  13. A comparison between thermal-optical transmittance elemental carbon measured by different protocols in PM2.5 samples.

    PubMed

    Giannoni, Martina; Calzolai, Giulia; Chiari, Massimo; Cincinelli, Alessandra; Lucarelli, Franco; Martellini, Tania; Nava, Silvia

    2016-11-15

    Although controlled procedures for the determination of carbonaceous fractions are of importance for any air quality measurements, currently no reference method for elemental carbon (EC) and organic carbon (OC) analysis is established yet in Europe. The implementation of the different thermal evolution protocols available in the literature, differing in temperature and duration of the heating ramps, affects the results and can result in a wide variation of EC and OC values. In this study three different protocols for thermal-optical-transmittance analysis of EC and OC were compared, namely He-870 (a variation of the NIOSH protocol), He-550 (a proxy of the IMPROVE protocol), and EUSAAR_2. Measurements were carried out on PM2.5 samples collected on Quartz fibre filters in three sites of different typology: urban background and urban traffic in Florence (Italy) and regional background in Livorno (Italy). The samples were analysed before and after a washing procedure to remove possible water-soluble organic compounds (WSOC), which may enhance the charring process, complicating the EC quantification. This study evidenced a very good agreement for TC measurement (at 2-3% level) and some discrepancies in EC measurement (up to 40%), as expected. WSOC and Pyrolitic Carbon (PyC) present a good correlation, independently of site typology, demonstrating that water soluble compound can be responsible of charring mechanism during the He phase.

  14. Organic double layer element driven by triboelectric nanogenerator: Study of carrier behavior by non-contact optical method

    NASA Astrophysics Data System (ADS)

    Chen, Xiangyu; Taguchi, Dai; Manaka, Takaaki; Iwamoto, Mitsumasa

    2016-02-01

    By using optical electric-field-induced second-harmonic generation (EFISHG) technique, we studied carrier behavior caused by contact electrification (CE) in an organic double-layer element. This double-layer sample was half suspended in the open air, where one electrode (anode or cathode) was connected with a Cu foil for electrification while the other electrode was floated. Results showed two distinct carrier behaviors, depending on the (anode or cathode) connections to the Cu foil, and these carrier behaviors were analyzed based on the Maxwell-Wagner model. The double-layer sample works as a simple solar cell device. The photovoltaic effect and CE process have been proved to be two paralleled effects without strong interaction with each other, while photoconductivity changing in the sample can enhance the relaxation of CE induced charges. By probing the carrier behavior in this half-suspended device, the EFISHG technique has been demonstrated to be an effective non-contact method for clarifying the CE effect on related energy harvesting devices and electronics devices. Meanwhile, the related physical analysis in this letter is also useful for elucidating the fundamental characteristic of hybrid energy system based on solar cell and triboelectric nanogenerator.

  15. Quality assurance and quality control for thermal/optical analysis of aerosol samples for organic and elemental carbon.

    PubMed

    Chow, Judith C; Watson, John G; Robles, Jerome; Wang, Xiaoliang; Chen, L-W Antony; Trimble, Dana L; Kohl, Steven D; Tropp, Richard J; Fung, Kochy K

    2011-12-01

    Accurate, precise, and valid organic and elemental carbon (OC and EC, respectively) measurements require more effort than the routine analysis of ambient aerosol and source samples. This paper documents the quality assurance (QA) and quality control (QC) procedures that should be implemented to ensure consistency of OC and EC measurements. Prior to field sampling, the appropriate filter substrate must be selected and tested for sampling effectiveness. Unexposed filters are pre-fired to remove contaminants and acceptance tested. After sampling, filters must be stored in the laboratory in clean, labeled containers under refrigeration (<4 °C) to minimize loss of semi-volatile OC. QA activities include participation in laboratory accreditation programs, external system audits, and interlaboratory comparisons. For thermal/optical carbon analyses, periodic QC tests include calibration of the flame ionization detector with different types of carbon standards, thermogram inspection, replicate analyses, quantification of trace oxygen concentrations (<100 ppmv) in the helium atmosphere, and calibration of the sample temperature sensor. These established QA/QC procedures are applicable to aerosol sampling and analysis for carbon and other chemical components.

  16. Comparison of parallel flow and concentric micronebulizers for elemental determination in lubricant oil, residual fuel oil and biodiesel by Inductively Coupled Plasma Optical Emission Spectrometry

    NASA Astrophysics Data System (ADS)

    de Souza, Jefferson R.; dos Santos, Eider Fernando; Duyck, Christiane B.; Saint'Pierre, Tatiana D.

    2011-05-01

    Two micronebulizers, PFA-100 and Miramist, were evaluated using a method for elemental determination by Inductively Coupled Plasma Optical Emission Spectrometry (ICP OES) in lubricant and residual fuel oils diluted in xylene. The facility and speed of direct sample dilution in organic solvents, without additional pretreatment, combined with the multielemental capacity and robustness of ICP OES are advantageous. The operational conditions were optimized through factorial design. Improvement in the signal-to-background ratio was observed for Ag, Al, B, Ba, Ca, Cr, Cu, Fe, Mn, Si, Ti and V. Higher sensitivity was obtained with the PFA-100 micronebulizer, although the limits of detection (LOD) obtained for both micronebulizers were similar, between 0.3 μg kg -1 (Mg) and 18 μg kg -1 (Ni). The certified reference materials NIST 1634c and NIST 1085b were used for method validation and good recoveries were obtained with values between 93% (Pb) and 102% (P) for PFA-100 and 90% (Pb) and 103% (P) for Miramist. The method was also validated for analysis of biodiesel samples by recovery tests, with results from 89% to 103%. The proposed method was employed for the analysis of crude oil, lubricant oil and biodiesel from different raw materials.

  17. Environmental biomonitoring of essential and toxic elements in human scalp hair using accelerated microwave-assisted sample digestion and inductively coupled plasma optical emission spectroscopy.

    PubMed

    Kumakli, Hope; Duncan, A'ja V; McDaniel, Kiara; Mehari, Tsdale F; Stephenson, Jamira; Maple, Lareisha; Crawford, Zaria; Macemore, Calvin L; Babyak, Carol M; Fakayode, Sayo O

    2017-05-01

    Human scalp hair samples were collected and used to assess exposure to toxic elements and essential elements in the state of North Carolina, USA using accelerated microwave assisted acid digestion and inductively coupled plasma optical emission spectroscopy (ICP-OES). The figures-of-merit of the ICP-OES were appropriate for elemental analysis in scalp hair with detection limits as low as 0.0001 mg/L for Cd, good linearity (R(2) > 0.9978), and percent recoveries that ranged from 96 to 106% for laboratory-fortified-blanks and 88-112% for sample spike recovery study. The concentrations of essential elements in scalp hair were larger than those of toxic elements, with Ca having the highest average concentration (3080 μg/g, s = 14,500, n = 194). Some of the maximum concentrations observed for As (65 μg/g), Ni (331 μg/g), Cd (2.96 μg/g), and Cr (84.6 μg/g) in individual samples were concerning, however. Samples were statistically analyzed to determine the influence of race, gender, smoking habits, or age on the elemental concentrations in scalp hair. Higher concentrations of essential elements were observed in the scalp hair of Caucasians, females, and non-smokers, and the differences were often significant at a 90% confidence level. Several pairs of essential elements, for example Ca-K, Ca-Mg, and Ca-Zn, were strongly correlated in Caucasian hair but uncorrelated in African-American hair. Similarly, essential elements were strongly correlated in female hair but weakly correlated in male hair. Toxic element pairs (As-Cd, As-Se, Pb-As, and Se-Cd) were strongly correlated in the hair of smokers but uncorrelated in that of non-smokers, suggesting that cigarette smoke is a common source of toxic elements in humans.

  18. Uranium hydrogeochemical and stream sediment reconnaissance of the Dalhart NTMS quadrangle, New Mexico/Texas/Oklahoma, including concentrations of forty-two additional elements

    SciTech Connect

    Morgan, T.L.

    1980-08-01

    Totals of 1583 water samples and 503 sediment samples were collected from 2028 locations within the 20 000-km/sup 2/ area of the quadrangle at an average density of one location per 9.86 km/sup 2/. Water samples were collected from wells, springs, and streams and were analyzed for uranium. Sediment samples were collected from streams and springs and were analyzed for uranium, thorium, and 41 additional elements. All field and analytical data are listed in the appendixes of this report. Discussion is limited to anomalous samples, which are considered to be those containing over 20 ppB uranium for waters and over 5 ppM uranium for sediments. Uranium concentrations in water samples range from below the detection limit of 0.2 ppB to 1457.65 ppB and average 7.41 ppB. Most of the seventy anomalous water samples (4.4% of all water samples) are grouped spatially into five clusters or areas of interest. Samples in three of the clusters were collected along the north edge of the quadrangle where Mesozoic strata are exposed. The other two clusters are from the central and southern portions where the Quaternary Ogallala formation is exposed. Sediment samples from the quadrangle have uranium concentrations that range from 0.90 ppM to 27.20 ppM and average 3.27 ppM. Fourteen samples (2.8% of all sediment samples) contain over 5 ppM uranium and are considered anomalous. The five samples with the highest concentrations occur where downcutting streams expose Cretaceous units beneath the Quaternary surficial deposits. The remaining anomalous sediment samples were collected from scattered locations and do not indicate any single formation or unit as a potential source for the anomalous concentrations.

  19. Optical techniques as validation tools for finite element modeling of biomechanical structures, demonstrated in bird ear research

    NASA Astrophysics Data System (ADS)

    Muyshondt, Pieter; De Greef, Daniël; Soons, Joris; Dirckx, Joris J. J.

    2014-05-01

    In this paper we demonstrate the potential of stroboscopic digital holography and laser vibrometry as tools to gather vibration data and validate modelling results in complex biomechanical systems, in this case the avian middle ear. Whereas the middle ear of all mammal species contains three ossicles, birds only feature one ossicle, the columella. Despite this far simpler design, the hearing range of most birds is comparable to mammals, and is adapted to operate under very diverse atmospheric circumstances. This makes the investigation of the avian middle ear potentially very meaningful, since it could provide knowledge that can improve the design of prosthetic ossicle replacements in humans such as a TORP (Total Ossicle Replacement Prosthesis). In order to better understand the mechanics of the bird's hearing, we developed a finite element model that simulates the transmission of an incident acoustic wave on the eardrum via the middle ear structures to the fluid of the inner ear. The model is based on geometry extracted from stained μCT data and is validated using results from stroboscopic digital holography measurements on the eardrum and LDV measurements on the columella footplate. This technique uses very short high-power laser pulses that are synchronized to the membrane's vibration phase to measure the dynamic response of the bird's eardrum to an incident acoustic stimulus. Vibration magnitude as well as phase relative to the sound wave can be deduced from the results, the latter being of great importance in the elastic characterization of the tympanic membrane. In this work, the setup and results from the optical measurements, as well as the properties and optimization of the finite element model are presented. Observed phase variations across the eardrum's surface on the holography results strongly suggest the presence of internal energy losses in the membrane due to damping. Therefore, a viscoelastic characterisation of the model based on a complex

  20. Optical absorption measurement system

    DOEpatents

    Draggoo, Vaughn G.; Morton, Richard G.; Sawicki, Richard H.; Bissinger, Horst D.

    1989-01-01

    The system of the present invention contemplates a non-intrusive method for measuring the temperature rise of optical elements under high laser power optical loading to determine the absorption coefficient. The method comprises irradiating the optical element with a high average power laser beam, viewing the optical element with an infrared camera to determine the temperature across the optical element and calculating the absorption of the optical element from the temperature.

  1. Diamond turned master molds for bulk casting of sol-gel silica diffractive optical elements. Final report

    SciTech Connect

    Maxey, L.C.; Nogues, J.L.; Moreshead, B.

    1997-08-01

    This CRADA has combined the resources of a national laboratory and an innovative small company to investigate the production of diffractive lenses in silica glass, using diamond turned master molds. The method for producing these lenses combines the unique characteristics of the sol-gel silica replication process, pioneered by Geltech, with the state-of-the-art diamond turning expertise of the Oak Ridge Centers for Manufacturing Technology (ORCMT). A conventional lens focuses light by using a curved surface to refract (or bend) the incoming light so that it will form an image. These lenses are usually thick glass elements with one or both surfaces shaped into convex or concave spherical shapes. Traditionally, these lenses are produced by grinding and polishing the glass to the desired shape. Light can also be focused using the phenomenon of diffraction, rather than refraction. A lens of this type uses precision microscopic surface features to bend the light so that it forms an image. The result is a lens that is thinner and lighter than its refractive counterpart. Production of diffractive lenses requires the ability to accurately produce the precision microscopic features necessary to achieve controlled diffraction. Diffractive lenses have, for the most part, been limited to infra-red applications because the manufacturing technologies available have not enabled their use at visible wavelengths. Except in limited applications, these lenses have remained laboratory curiosities, because they must be individually produced by diamond turning infra-red optical materials. Geltech`s sol-gel silica replication process offers the opportunity to mass produce diffractive lenses in high quality silica glass. These lenses can be produced by diamond turning the necessary precision microscopic surface features into master surfaces that are replicated into intermediate molds. These molds are then used to produce a batch of diffractive lenses using the sol-gel process.

  2. Uranium hydrogeochemical and stream sediment reconnaissance data release for the Elk City NTMS Quadrangle, Idaho/Montana, including concentrations of forty-five additional elements

    SciTech Connect

    Broxton, D.E.; Beyth, M.

    1980-07-01

    Totals of 1580 water and 1720 sediment samples were collected from 1754 locations in the quadrangle. Elemental concentration, field measurement, weather, geologic, and geographic data for each sample location are listed for waters in Appendix I-A and for sediments in Appendix I-B. Uranium/thorium ratios for sediment samples are also included in Appendix I-B. All elemental analyses were performed at the LASL. Water samples were initially analyzed for uranium by fluorometry. All water samples containing more than 40 parts per billion (ppB) uranium were reanalyzed by delayed-neutron counting (DNC). A supplemental report containing the multielement analyses of water samples will be open filed in the near future. Sediments were analyzed for uranium and thorium as well as aluminum, antimony, arsenic, barium, beryllium, bismuth, cadmium, calcium, cerium, cesium, chlorine, chromium, cobalt, copper, dysprosium, europium, gold, hafnium, iron, lanthanum, lead, lithium, lutetium, magnesium, manganese, nickel, niobium, potassium, rubidium, samarium, selenium, scandium, silver, sodium, strontium, tantalum, terbium, tin, titanium, tungsten, vanadium, ytterbium, zinc, and zirconium. Basic statistics for 40 of these elements are presented. All sediments were analyzed for uranium by delayed-neutron counting. Other elemental concentrations in sediments were determined by neutron-activation analysis for 30 elements, by x-ray fluorescence for 12 elements, and by arc-source emission spectrography for 2 elements. Analytical results for sediments are reported as parts per million.

  3. Experimental validation of Monte Carlo and finite-element methods for the estimation of the optical path length in inhomogeneous tissue

    NASA Astrophysics Data System (ADS)

    Okada, Eiji; Schweiger, Martin; Arridge, Simon R.; Firbank, Michael; Delpy, David T.

    1996-07-01

    To validate models of light propagation in biological tissue, experiments to measure the mean time of flight have been carried out on several solid cylindrical layered phantoms. The optical properties of the inner cylinders of the phantoms were close to those of adult brain white matter, whereas a range of scattering or absorption coefficients was chosen for the outer layer. Experimental results for the mean optical path length have been compared with the predictions of both an exact Monte Carlo (MC) model and a diffusion equation, with two differing boundary conditions implemented in a finite-element method (FEM). The MC and experimental results are in good agreement despite poor statistics for large fiber spacings, whereas good agreement with the FEM prediction requires a careful choice of proper boundary conditions. measurement, Monte Carlo method, finite-element method.

  4. Effect on the morphology and optical properties of CH3NH3PbI3 with additive of NH4Cl

    NASA Astrophysics Data System (ADS)

    Yan, Xiaoliang; Yang, Xiao; Wang, Ruizhi; Li, Heng; Sheng, Chuanxiang

    2017-02-01

    Rapid emergence of solar cells based on mixed organic-inorganic halide perovskite have led to high power conversion efficiencies of over 20% in recent years. Looking for a simple and convenient way to fine-control of the perovskite film morphology is becoming one of the main issues. In this work, we explore the effect of adding NH4Cl on crystallization process and optical properties of perovskite. With adding NH4Cl, the perovskite films prepared by one-step method present better morphology than films without adding NH4Cl, namely, smoother surface and better coverage which result in uniform and much more stable photoluminescence intensities as well as longer lifetime of photoexcitations. More importantly, the photovoltaic cells fabricated with the addition of the NH4Cl have far better performance than the cells without additives. Therefore, one-step fabrication method can also control the morphology of perovskite films finely for both optical application and solar cells with adding proper additive.

  5. Manufacturing methods of testing the large-sized optics at the stage of grinding, aspherical surface centering, and interface elements positioning before gluing

    NASA Astrophysics Data System (ADS)

    Semenov, Aleksandr P.; Abdulkadyrov, Magomed A.; Patrikeev, Vladimir E.

    2016-07-01

    The article describes the method of testing the absolute profile of large-sized astronomical mirrors grinded aspherical surface and the method of test the aspherical surface decentering relative to the astronomical mirror geometrical center by means of a linear three-point spherometer, which is subsequently moved perpendicular to the direction from the optical surface center to the edge, as well as the method of positioning the interface elements being glued.

  6. Fabrication of NIL templates and diffractive optical elements using the new Vistec SB4050 VSB e-beam writer

    NASA Astrophysics Data System (ADS)

    Butschke, Joerg; Irmscher, Mathias; Koepernik, Corinna; Martens, Stephan; Sailer, Holger; Schnabel, Bernd

    2015-03-01

    Targeting mass production of nanostructures, nanoimprint lithography (NIL) is one of the most cost-effective ways to do so. One of the most critical topics is the pattern quality of the imprint master template. Therefore the new Vistec SB4050 VSB e-beam writer has been evaluated regarding its capability for state-of-the-art NIL template and DOE making. Equipped with a new air bearing stage the tool can expose a wide variety of substrates including large and heavy ones. For 9035 substrates a placement accuracy of 9nm (3sigma) as well as an overlay accuracy of 7nm (3sigma) with a mean error below 2nm has been achieved. Targeting for minimum feature size, a resolution below 30nm has been achieved for both, dense lines and holes pattern even using CAR. In addition, 3D structuring capability has been proved by applying GenISys' Layout Beamer calibrated for an appropriate negative tone resist. Further investigation has been done on shot count optimization regarding circular holes respective pillars. Using a feature size dependent segmentation, writing time reduction could be achieved keeping the original feature shape. Besides screening of typical tool parameter an application driven evaluation has been done by fabricating different type of templates based on silicon and quartz. 2D and 3D features have been realized. Furthermore holograms have been fabricated and proved for their performance by optical measurements.

  7. Five beam holographic lithography for simultaneous fabrication of three dimensional photonic crystal templates and line defects using phase tunable diffractive optical element.

    PubMed

    Lin, Yuankun; Harb, Ahmad; Lozano, Karen; Xu, Di; Chen, K P

    2009-09-14

    This paper demonstrates an approach for laser holographic patterning of three-dimensional photonic lattice structures using a single diffractive optical element. The diffractive optical element is fabricated by recording gratings in a photosensitive polymer using a two-beam interference method and has four diffraction gratings oriented with four-fold symmetry around a central opening. Four first-order diffracted beams from the gratings and one non-diffracted central beam overlap and form a three-dimensional interference pattern. The phase of one side beam is delayed by inserting a thin piece of microscope glass slide into the beam. By rotating the glass slide, thus tuning the phase of the side beam, the five beam interference pattern changes from face-center tetragonal symmetry into diamond-like lattice symmetry with an optimal bandgap. Three-dimensional photonic crystal templates are produced in a photoresist and show the phase tuning effect for bandgap optimization. Furthermore, by integrating an amplitude mask in the central opening, line defects are produced within the photonic crystal template. This paper presents the first experimental demonstration on the holographic fabrication approach of three-dimensional photonic crystal templates with functional defects by a single laser exposure using a single optical element.

  8. Uranium hydrogeochemical and stream sediment reconnaissance data release for the Dubois NTMS Quadrangle, Idaho/Montana, including concentrations of forty-five additional elements

    SciTech Connect

    LaDelfe, C.M.

    1980-08-01

    Totals of 1024 water samples and 1600 sediment samples were collected from 1669 locations in the Dubois quadrangle. Water samples were taken at streams, springs, and wells; sediment samples were collected from streams and springs. All field and analytical data are presented for waters in Appendix I-A and for sediments in I-B. All elemental analyses were performed at the LASL. Water samples were initially analyzed for uranium by fluorometry. All water samples containing more than the upper detection limit of uranium were reanalyzed by delayed neutron counting. Sediments were analyzed for uranium and thorium as well as aluminum, antimony, arsenic, barium, beryllium, bismuth, cadmium, calcium, cerium, cesium, chlorine, chromium, cobalt, copper, dysprosium, europium, gold, hafnium, iron, lanthanum, lead, lithium, lutetium, magnesium, manganese, nickel, niobium, potassium rubidium, samarium, scandium, selenium, silver, sodium, strontium, tantalum, terbium, tin, titanium, tungsten, vanadium, ytterbium, zinc and zirconium. All sediments were analyzed for uranium by delayed-neutron counting. Other elemental concentrations in sediments were determined by neutron-activation analysis for 30 elements, by x-ray fluorescence for 12 elements, and by arc-source emission spectrography for 2 elements. Analytical results for sediments are reported as parts per million.

  9. Imaging of elements in leaves of tobacco by solid sampling-electrothermal vaporization-inductively coupled plasma-optical emission spectrometry

    NASA Astrophysics Data System (ADS)

    Masson, Pierre

    2014-12-01

    Plants take up and store elements according to the environment in which they are growing. Because plants are at the base of the food chain, the determination of essential elements or toxic elements in plant materials is of importance. However, it is assumed that the element content determined on selected tissues may provide more specific information than that derived from the whole plant analysis. In this work, we assessed the feasibility of solid sampling-electrothermal vaporization-inductively coupled plasma-optical emission spectrometry analyses for quantitative imaging of Cd and Mg in plant leaves. Leaves of tobacco (Nicotiana tabacum) were selected to be used as samples. To produce a two dimensional image, sections cut from leaf samples were analyzed. Cellulose doped with multi-element solution standards was used as calibration samples. Two certified reference materials (NIST SRM 1547 Peach Leaves and NIST SRM 1573a Tomato leaves) were used to verify the accuracy of measurements with good agreement between the measured concentrations and the certified values. Quantitative imaging revealed the inhomogeneous distribution of the selected elements. Excess of Cd and Mg tended to be focused on peripheral regions and the tip of the leaf.

  10. Performance analysis of precoding-based asymmetrically clipped optical orthogonal frequency division multiplexing wireless system in additive white Gaussian noise and indoor multipath channel

    NASA Astrophysics Data System (ADS)

    Ranjha, Bilal; Zhou, Zhou; Kavehrad, Mohsen

    2014-08-01

    We have compared the bit error rate (BER) performance of precoding-based asymmetrically clipped optical orthogonal frequency division multiplexing (ACO-OFDM) and pulse amplitude modulated discrete multitone (PAM-DMT) optical wireless (OW) systems in additive white Gaussian noise (AWGN) and indoor multipath frequency selective channel. Simulation and analytical results show that precoding schemes such as discrete Fourier transform, discrete cosine transform, and Zadoff-Chu sequences do not affect the performance of the OW systems in the AWGN channel while they do reduce the peak-to-average power ratio (PAPR) of the OFDM output signal. However, in a multipath indoor channel, using zero forcing frequency domain equalization precoding-based systems give better BER performance than their conventional counterparts. With additional clipping to further reduce the PAPR, precoding-based systems also show better BER performance compared to nonprecoded systems when clipped relative to the peak of nonprecoded systems. Therefore, precoding-based ACO-OFDM and PAM-DMT systems offer better BER performance, zero signaling overhead, and low PAPR compared to conventional systems.

  11. Uranium hydrogeochemical and stream sediment reconnaissance data release for the Lewistown NTMS Quadrangle, Montana, including concentrations of forty-two additional elements

    SciTech Connect

    Shannon, S.S. Jr.

    1980-08-01

    Totals of 758 water and 1170 sediment samples were collected from 1649 locations in the Levistown quadrangle. Water samples were collected at streams, springs, wells, ponds, and marshes; sediment samples were obtained from streams, springs, and ponds. Histograms and statistical data for uranium concentrations in water and sediment samples and thorium concentrations in sediment samples are given. All samples were collected at the nominal reconnaissance density of one sample location per 10 km/sup 2/. Elemental concentration, field measurement, weather, geologic, and geographic data for each sample location are listed for waters and for sediments. Uranium to thorium (U/Th) ratios for sediment samples are included. Water samples were initially analyzed for uranium by fluorometry. All water samples containing more than 40 ppB U were reanalyzed by delayed-neutron counting. Sediments were analyzed for U and Th as well as Al, Sb, Ba, Be, Bi, Cd, Ca, Ce, Cs, Cl, Cr, Co, Cu, Dy, Eu, Au, Hf, Fe, La, Pb, Li, Lu, Mg, Mn, Ni, Nb, K, Rb, Sa, Sc, Ag, Na, Sr, Ta, Tb, Sn, Ti, W, V, Yb, and Zn. All sediments were analyzed for U by delayed neutron counting. Other elemental concentrations in sediments were determined by neutron activation analysis for 31 elements, by x-ray fluorescence for 9 elements, and by arc-source emission spectrography for 2 elements. Analytical results are reported as parts per million. Descriptions of procedures used for analysis of water and sediments samples as well as analytical precisions and detection limits are given.

  12. A simplified soil extraction sequence to monitor the main and trace element speciation in soil after compost and mineral fertilizer additions upon the composition of wheat grains

    NASA Astrophysics Data System (ADS)

    Sager, Manfred; Erhart, Eva

    2016-04-01

    High quality biological waste treatment aims at producing compost in order to maintain a clean environment and to sustain soil organic carbon levels. Fertilization with compost as a source of organic carbon, nutrients, and accessory elements, as well as fertilization with mineral N- and PK fertilizer have been tested in a field experiment on a calcaric Fluvisol in the Danube wetlands, at 4 levels each. Yields of wheat were recorded, and grains and soils were sampled from each treatment, and analyzed for main and trace element composition. The corresponding soils were characterized by mobile phases, obtained by leaching with 0,16M acetic acid to cover exchangeables plus carbonates, and subsequently by 0,1M oxalate buffer pH 3 to dissolve the pedogenic oxides. Total amounts were obtained from digests with perchloric- nitric-hydrofluoric acid. For quasi-total amounts, aqua regia was replaced by pressure decomposition with KClO3 in dilute nitric acid. The proposed extraction sequence permits to analyze and interpret soil for main elements, trace elements, nutrients and anions simultaneously. Factor analyses of soil extracts obtained from dilute acetic acid revealed Ba-Be-Cd-Cu-Li-S (traces), Ca-Mg-Mn (main carbonates), Al-Fe-B, Y, and P-K (nutrients) as chemically feasible principal components. Subsequent soil extracts from oxalate contained Al-B-Co-K-Na-Pb-Si-V-S (maybe acid silicate weathering), Cr-Li-Ni-Sr-Ti (maybe basic silicate weathering), Be-Cu-Fe-P, Co-Mg-Mn-Zn (Mn-oxides) and Ba-Sc as principal components. Factor analyses of total element data distinguished the principal components Ce-La-Li-Sc-Y-P (rare earths), Al-Ca-Fe-K-Mg-Na-P (main elements), Cd-Co-Cr-Cu-Ni-Zn (trace elements), As-Pb (contaminants), Ba-Mn-Sr, and Ti, which looks chemically feasible also. Factor analyses of those soil fractions which presumably form the main fractions of exchangeables, carbonates, pedogenic oxides and silicates, showed no cross connections, except for P. Oxalate

  13. Addition effect of SnO in optical property of Bi{sub 2}O{sub 3}-containing aluminoborate glass

    SciTech Connect

    Masai, Hirokazu; Takahashi, Yoshihiro; Fujiwara, Takumi

    2009-04-15

    We have found that an addition of SnO in a bismuth-containing aluminoborate glass, (CaO-B{sub 2}O{sub 3}-Bi{sub 2}O{sub 3}-Al{sub 2}O{sub 3}-TiO{sub 2}) (CaBBAT), decreases both the optical absorption coefficient in the visible region and the relative intensity of x-ray photoelectron spectroscopy (XPS) signal at 157 eV. Since signal intensity of electron spin resonance (ESR) at g=1.95 also decreased with increasing amount of SnO, it is suggested that bismuth radical-like species exist in the glass and that SnO reacts with the bismuth species. Concentration dependence of SnO in the XPS and in the ESR spectra shows that we can assign the observed signal to bismuth radical species in the glass. We, therefore, conclude that there is qualitative correlation between the optical absorption in the visible region and bismuth radical species in the CaBBAT glass.

  14. Influence of CsCl addition on the nanostructured voids and optical properties of 80GeS2-20Ga2S3 glasses

    NASA Astrophysics Data System (ADS)

    Klym, H.; Ingram, A.; Shpotyuk, O.; Karbovnyk, I.

    2016-09-01

    The influence of CsCl content on the void evolution in (80GeS2-20Ga2S3)100-x(CsCl)x, x = 0; 5; 10; 15, chalcogenide glasses and changes of the optical response of these glasses due to CsCl addition are investigated. It is shown that structural agglomeration of voids occurs at addition and increasing of CsCl amount in base glasses. Supersaturation of GeS2-Ga2S3-CsCl glasses by CsCl results in the contraction of void volumes in (80GeS2-20Ga2S3)85(CsCl)15. By applying positron-positronium decomposition algorithm it was established that CsCl not only transforms voids in glass, but also forms new positron-trapping sites in Ge-Ga-S glassy matrix. Therefore, CsCl addition results in the shift of fundamental transmission edge in the visible region. It is shown that doping by larger concentrations of CsCl may lead to "supersaturation" of base glasses and that adding 10 mol% of CsCl is apparently an optimal doping level in view of further modification of glasses with rare-earth ions.

  15. C- and N-Selective Grignard Addition Reactions of α-Aldimino Esters in the Presence or Absence of Zinc(II) Chloride: Synthetic Applications to Optically Active Azacycles.

    PubMed

    Hatano, Manabu; Yamashita, Kenji; Ishihara, Kazuaki

    2015-05-15

    Highly practical synthetic methods were developed for the C- and N-selective Grignard addition reactions of N-4-MeOC6H4-protected α-aldimino esters in the presence or absence of zinc(II) chloride. Diastereoselective C-alkyl addition, tandem C-alkyl addition-N-alkylation, and some transformations to synthetically useful optically active azacycles were demonstrated.

  16. Research of the Additional Losses Occurring in Optical Fiber at its Multiple Bends in the Range Waves 1310nm, 1550nm and 1625nm Long

    NASA Astrophysics Data System (ADS)

    Yurchenko, A. V.; Gorlov, N. I.; Alkina, A. D.; Mekhtiev, A. D.; Kovtun, A. A.

    2016-01-01

    Article is devoted to research of the additional losses occurring in the optical fiber at its multiple bends in the range waves of 1310 nanometers, 1550 nanometers and 1625 nanometers long. Article is directed on creation of the external factors methods which allow to estimate and eliminate negative influence. The automated way of calculation of losses at a bend is developed. Results of scientific researches are used by engineers of “Kazaktelekom” AS for practical definition of losses service conditions. For modeling the Wolfram|Alpha environment — the knowledge base and a set of computing algorithms was chosen. The greatest losses are noted on wavelength 1310nm and 1625nm. All dependences are nonlinear. Losses with each following excess are multiplicative.

  17. Fully parallel adaptive finite element simulation using the simplified spherical harmonics approximations for frequency-domain fluorescence-enhanced optical imaging

    NASA Astrophysics Data System (ADS)

    Lu, Yujie; Zhu, Banghe; Shen, Haiou; Rasmussen, John C.; Wang, Ge; Sevick-Muraca, Eva M.

    2011-03-01

    Fluorescence-enhanced optical imaging/tomography may play an important role in preclinical research and clinical diagnostics as a type of optical molecular. Time- and frequency-domain measurement can acquire more measurement information, reducing the ill-posedness and improving the reconstruction quality of fluorescence-enhanced optical tomography. Although the diffusion approximation (DA) theory has been extensively in optical imaging, high-order photon migration models must be further investigated for application to complex and small tissue volumes. In this paper, a frequency-domain fully parallel adaptive finite element solver is developed with the simplified spherical harmonics (SPN) approximations. To fully evaluate the performance of the SPN approximations, a fast tetrahedron-based Monte Carlo simulator suitable for complex heterogeneous geometries is developed using the convolution strategy to realize the simulation of the fluorescence excitation and emission. With simple and real digital mouse phantoms, the results show that the significant precision and speed improvements are obtained from the parallel adaptive mesh evolution strategy.

  18. [Determination of nine hazardous elements in textiles by inductively coupled plasma optical emission spectrometer after microwave-assisted dilute nitric acid extraction].

    PubMed

    Chen, Fei; Xu, Dian-dou; Tang, Xiao-ping; Cao, Jing; Liu, Ya-ting; Deng, Jian

    2012-01-01

    Textiles are easily contaminated by heavy metals in the course of processing. In order to monitor the quality of textiles, a new method was developed for simultaneous determination of arsenic, antimony, lead, cadmium, chromium, cobalt, copper, nickel and mercury in textiles by inductively coupled plasma optical emission spectrometry (ICP-OES) after microwave-assisted dilute nitric acid extraction. After optimizing extraction conditions, we ultimately selected 5% nitric acid as extractant and 5 min as extraction time with the extraction temperature of 120 degrees C and instrument power of 400W in the microwave-assisted extraction procedure. Nine hazardous elements were detected sequentially by ICP-OES. The results showed that the detection limits were 0.3-15 microg x L(-1) and the recoveries 73.6%-105% with the RSDs (n = 3) of 0.1%-3%. The proposed method was successfully used to determine nine elements in cotton, wool, terylene and acrylic.

  19. A fast method for apatite selective leaching from granitic rocks followed through rare earth elements and phosphorus determination by inductively coupled plasma optical emission spectrometry.

    PubMed

    Gásquez, José A; DeLima, Edmilson; Olsina, Roberto A; Martinez, Luis D; de la Guardia, Miguel

    2005-10-15

    Rare earth elements (REE) and phosphorus (P) in apatite were determined using inductively coupled plasma optical emission spectrometry (ICP-OES) after partial dissolution of the granitic rocks and pure apatite. The dissolution was performed with nitric acid in an open system and the matrix elements were separated by a cation exchange procedure. Samples of pure apatite from granitic rocks were dissolved with, 0.14 mol L(-1) nitric acid. The results showed that the release of REE is due to apatite leaching because it could be assessed by comparing the chondrite-normalised pattern corresponding to the rocks and the pure apatite. Similar results were found for absolute REE abundance from the partial dissolution of the rocks and pure apatite. This simple and rapid method can be applied for the determination of REE in apatite as an indicator for mineral exploration, although its use in petrology could be possible.

  20. Inductively coupled plasma optical emission spectrometry for trace multi-element determination in vegetable oils, margarine and butter after stabilization with propan-1-ol and water

    NASA Astrophysics Data System (ADS)

    de Souza, Roseli M.; Mathias, Bárbara M.; da Silveira, Carmem Lúcia P.; Aucélio, Ricardo Q.

    2005-06-01

    The quantitative evaluation of trace elements in foodstuffs is of considerable interest due to the potential toxicity of many elements, and because the presence of some metallic species might affect the overall quality (flavor and stability) of these products. In the present work, an inductively coupled plasma optical emission spectrometric method has been developed for the determination of six elements (Cd, Co, Cr, Cu, Ni and Mn) in olive oil, soy oil, margarine and butter. Organic samples (oils and fats) were stabilized using propan-1-ol and water, which enabled long-time sample dispersion in the solution. This simple sample preparation procedure, together with an efficient sample introduction strategy (using a Meinhard K3 nebulizer and a twister cyclonic spray chamber), facilitated the overall analytical procedure, allowing quantification using calibration curves prepared with inorganic standards. Internal standardization (Sc) was used for correction of matrix effects and signal fluctuations. Good sensitivities with limits of detection in the ng g -1 range were achieved for all six elements. These sensitivities were appropriate for the intended application. The method was tested through the analysis of laboratory-fortified samples with good recoveries (between 91.3% and 105.5%).

  1. Bent approximations to synchrotron radiation optics

    SciTech Connect

    Heald, S.

    1981-01-01

    Ideal optical elements can be approximated by bending flats or cylinders. This paper considers the applications of these approximate optics to synchrotron radiation. Analytic and raytracing studies are used to compare their optical performance with the corresponding ideal elements. It is found that for many applications the performance is adequate, with the additional advantages of lower cost and greater flexibility. Particular emphasis is placed on obtaining the practical limitations on the use of the approximate elements in typical beamline configurations. Also considered are the possibilities for approximating very long length mirrors using segmented mirrors.

  2. Uranium hydrogeochemical survey of well waters from an area around Pie Town, Catron County, West-Central New Mexico, including concentrations of twenty-three additional elements

    SciTech Connect

    Morgan, T.L.; George, W.E.; Hensley, W.K.; Thomas, G.J.; Langhorst, A.L.

    1980-10-01

    As part of the Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) of the National Uranium Resource Evaluation (NURE) sponsored by the US Department of Energy (DOE), the Los Alamos Scientific Laboratory (LASL) conducted a detailed hydrogeochemical survey of well waters in a 4250-km/sup 2/ area near Pie Town in west-central New Mexico. A total of 300 well samples was collected and analyzed for uranium and 23 other elements. The results of these analyses and carbonate and bicarbonate ion concentrations are presented in the Appendixes of this report. Uranium concentrations range from below the detection limit of 0.02 parts per billion (ppB) to 293.18 ppB and average 8.71 ppB. Samples containing high levels of uranium were collected from the Largo Creek valley west of Quemado, from a small area about 6 km east of Quemado, from a small area surrounding Pie Town, and from scattered locations in the area surrounding Adams Diggings north of Pie Town. Most of the samples containing high uranium concentrations were collected from wells associated with the volcanic sedimentary facies of the Datil formation. This formation is a likely source of mobile uranium that may be precipitating in the underlying Baca formation, a known uranium host unit. Bicarbonate ion concentration, while proportional to uranium concentration in some cases, is not a strong controlling factor in the uranium concentrations in samples from this area.

  3. Impending anterior ischemic optic neuropathy with elements of retinal vein occlusion in a patient on interferon for polycythemia vera.

    PubMed

    Rue, Kelly S; Hirsch, Louis K; Sadun, Alfredo A

    2012-01-01

    We describe the course and likely pathophysiology of impending anterior ischemic optic neuropathy (AION) and retinal vein occlusion in a 56-year-old man with polycythemia vera managed with interferon alpha for 2 years. Our patient presented with decreased vision, scintillating scotomata, and floaters. Fundus examination findings and results of a fluorescein angiogram led to the diagnosis of impending AION and retinal vein occlusion. Considering that both polycythemia vera and interferon have possible influences on vascular occlusion and optic disc edema, we stopped interferon treatment and immediately attempted to treat the polycythemia vera empirically with pentoxifylline and any interferon-associated inflammation with prednisone. Our patient experienced complete resolution of fundus abnormalities and return of normal vision within 3 weeks, which may be attributed to our successful treatment of both etiologies. Thus, further study is warranted to elucidate the treatment of both polycythemia vera and interferon-induced impending AION.

  4. Design and finite element modeling of a novel optical microsystems-based tactile sensor for minimal invasive robotic surgery

    NASA Astrophysics Data System (ADS)

    Ghanbari Mardasi, Amir; Ghanbari, Mahmood; Salmani Tehrani, Mehdi

    2014-09-01

    Although recently Minimal Invasive Robotic Surgery (MIRS) has been more addressed because of its wide range of benefits, however there are still some limitations in this regard. In order to address the shortcomings of MIRS systems, various types of tactile sensors with different sensing principles have been presented in the last few years. In the present paper a MEMS-based optical sensor, which has been recently proposed by researchers, is investigated using numerical simulation. By this type of sensors real time quantification of both dynamic and statics contact forces between the tissue and surgical instrument would be possible. The presented sensor has one moving part and works based on the intensity modulation principle of optical fibers. It is electrically-passive, MRI-compatible and it is possible to be fabricated using available standard micro fabrication techniques. The behavior of the sensor has been simulated using COMSOL MULTIPHYSICS 3.5 software. Stress analysis is conducted on the sensor to assess the deflection of the moving part of the sensor due to applied force. The optical simulation is then conducted to estimate the power loss due to the moving part deflection. Using FEM modeling, the relation between force and deflection is derived which is necessary for the calibration of the sensor.

  5. The second and third optic ganglia of the worker bee: Golgi studies of the neuronal elements in the medulla and lobula.

    PubMed

    Ribi, W A; Scheel, M

    1981-01-01

    The gross morphology and the fine-structural characteristics of neurones of the second and third optic ganglia of the honeybee Apis mellifera were investigated light microscopically on the basis of Golgi (selective silver)- and reduced silver preparations. The second optic ganglion, the medulla, is ovoid in shape and has a slightly convex distal surface and a slightly concave proximal surface. The medullar outer levels are characteristically composed of neuronal arrangements showing strict precision of their geometrical spacing proximally as far as a pronounced layer of tangential fibre elements comprising the serpentine layer of the medulla. At the inner medullary levels retinotopic channels are again multiplied, and the arrangement of axons and dendrites contribute to a complex lattice. The third optic ganglion, the lobula, is interposed between the medulla and the protocerebrum. It is the site of termination of the third-order neurones. The lobula in hymenopterans appears, in contrast to dipterans, odonates and lepidopterans, as a single neuropilic mass. A short review of the electrophysiological data concerning these two ganglia has been tentatively correlated with some of the anatomical data.

  6. Compendation of SSC lattice optics in the presence of dipole field errors: Report of the Correction Element Working Group

    SciTech Connect

    Bintinger, D.; Chao, A.; Forest, E.

    1989-02-01

    The assignment of the Correction Element Working Group (CEWG) is to advance the designs of various candidate correction schemes to a point where they can be compared and distilled down to a single plan. Choosing among, the options often involves consideration of incommensurate factors such as cost, practicality, and theoretical performance. Except for minor issues, the CEWG purpose is to gather and array the facts in a form from which these decisions can be rationally made, but not to make the decisions. The present report analyses various schemes for compensating nonlinear multipole errors in the main arc dipoles of the Superconducting Super Collider. Emphasis is on comparing lumped and distributed compensation, on minimizing the total number of correction elements, and on reducing the sensitivity to closed-orbit errors.

  7. Identification of minute damage in composite bridge structures equipped with fiber optic sensors using the location of neutral axis and finite element analysis

    NASA Astrophysics Data System (ADS)

    Li, Xi; Glisic, Branko

    2016-04-01

    By definition, the neutral axis of a loaded composite beam structure is the curve along which the section experiences zero bending strain. When no axial loading is present, the location of the neutral axis passes through the centroid of stiffness of the beam cross-section. In the presence of damage, the centroid of stiffness, as well as the neutral axis, shift from the healthy position. The concept of neutral axis can be widely applied to all beam-like structures. According to literature, a change in location of the neutral axis can be associated with damage in the corresponding cross-section. In this paper, the movement of neutral axis near locations of minute damage in a composite bridge structure was studied using finite element analysis and experimental results. The finite element model was developed based on a physical scale model of a composite simply-supported structure with controlled minute damage in the reinforced concrete deck. The structure was equipped with long-gauge fiber optic strain and temperature sensors at a healthy reference location as well as two locations of damage. A total of 12 strain sensors were installed during construction and used to monitor the structure during various loading events. This paper aims to explain previous experimental results which showed that the observed positions of neutral axis near damage locations were higher than the predicted healthy locations in some loading events. Analysis has shown that finite element analysis has potential to simulate and explain the physical behavior of the test structure.

  8. The determination of trace element concentrations in fly ash samples using ultrasound-assisted digestion followed with inductively coupled plasma optical emission spectrometry.

    PubMed

    Ilander, Aki; Väisänen, Ari

    2009-08-01

    A method of ultrasound-assisted digestion followed by inductively coupled plasma optical emission spectrometry (ICP-OES) used for the determination of trace element (chromium, copper, lead, nickel, vanadium and zinc) concentrations in fly ash samples was developed. All the measurements were performed in robust plasma conditions. Ultrasound-assisted digestion procedures using digestion solutions of aqua regia and hydrofluoric acid (HF) resulted in recovery rates of over 80% for all the analyte elements. Ultrasound-assisted two-step digestion with digestion solutions of 6mL of HNO(3) (Step 1) and 3mL of HNO(3)+3mL of HF (Step 2) resulted in recovery rates of over 92% for all the analyte elements with one exception, chromium, which had a recovery of about 85%. The analysis of SRM 1633b showed that the two-step ultrasound-assisted digestion method developed resulted in chromium, copper, nickel and zinc concentrations higher than the microwave digestion method standardized by the United States Environmental Protection Agency (USEPA method 3052). This is the very first time when a digestion method using ultrasound resulted in higher efficiency than microwave (USEPA method 3052) for chromium and nickel in very hard to dissolve samples. The major advantages of the ultrasound-assisted digestion over microwave digestion is the high treatment rate (about 30 samples simultaneously with a sonication time of 18min) and the possibility to use new sample vessels without a significant increase in costs.

  9. Chalcogenide and germanium hybrid optics

    NASA Astrophysics Data System (ADS)

    Cogburn, Gabriel

    2011-11-01

    When choosing a material to design infrared optics, an optical designer has to decide which material properties are most important to what they are trying to achieve. Factors include; cost, optical performance, index of material, sensor format, manufacturability, mechanical mounting and others. This paper will present an optical design that is made for a 640×480, 17μm sensor and is athermalized by using the material properties of chalcogenide glass and Germanium (Ge). The optical design will be a 3-element, f1.0 optic with an EFL of 20mm at 10μm. It consists of two Ge spherical lenses and a middle chalcogenide aspheric element. By using Ge and chalcogenide, this design utilizes the high index of Ge and combines it with the lower dn/dt of chalcogenide glass to provide an athermalized design without the use of additional electro-optical compensation inside the assembly. This study will start from the optical design process and explain the mechanical and optical properties of the design, then show the manufacturing process of molding an aspheric chalcogenide element. After the three elements are manufactured, they will be assembled and tested throughout the temperature range of -40 to 85°C to compare optical performance to design expectations. Ultimately, this paper will show that a high performance, athermalized optical assembly is possible to manufacture at a lower cost with the use of combining different infrared materials that allow for spherical Ge lenses and only one aspherical chalcogenide element which can be produced in higher volumes at lower costs through glass molding technology.

  10. High-contrast process using a positive-tone resist with antistatic coating and high-energy (100-keV) e-beam lithography for fabricating diffractive optical elements (DOE) on quartz

    NASA Astrophysics Data System (ADS)

    Poli, Louis C.; Kondek, Christine A.; Shoop, Barry L.; McLane, George F.

    1995-06-01

    Diffractive optical elements (DOE) are becoming important as optical signal processing elements in increasingly diverse applications. These elements, fabricated on quartz, may be used as phase shift type masks or as embedded components that implement a transfer function within a processing network. A process is under development for the fabrication of a DOE implementing a Jervis error diffusion kernel for research in half tone image processing. Dry etching is performed after lithography and pattern transfer through a nickel mask. This results in etched areal features on the substrate. An optical diffraction medium is thus created. Lithographic patterning is done by e-beam lithography (EBL) to realize small features, but also offers the important advantage of a large depth of field which relaxes the problem of complex surface topology. The recent availability of high energy (100 KeV) lithography tools provides a capability for precision overlay, small feature resolution, and enhanced image contrast through a lower induced proximity effect. Patterning by EBL on insulating substrates is complicated by the necessity of providing a vehicle for the avoidance of charge buildup on the surface. In a previously presented paper a methodology was shown for the use of TQV-501 (Nitto Chemical) antistatic compound as a final spin on film for use with PMMA and SAL-601 (Shipley). In this current work, a process is described using EBL and a high performance positive resist working with a final film layer of antistatic TQV-501 on a nickel coated wafer. The process may then be reapplied to realize additional lithographic levels in registration, for multilevel DOE components. High energy (100 KeV) EBL is used to provide high quality pattern definition. The e-beam sensitive resist, ZEP-320-37 (Nagase Chemical) in dilution, together with a top film layer of TQV-501 serves as a bilevel resist system and is used for patterning the desired image before definition of the nickel mask through

  11. Dammann gratings as integratable micro-optical elements created by laser micronanofabrication via two-photon photopolymerization.

    PubMed

    Chen, Qi-Dai; Lin, Xiao-Feng; Niu, Li-Gang; Wu, Dong; Wang, Wen-Quan; Sun, Hong-Bo

    2008-11-01

    Dammann gratings, as beam splitters and coherent signal generators, were produced in a short fabricating cycle by femtosecond laser fabrication via two-photon photopolymerization. These holograms that each generated 2x2, 3x3, 4x4, 5x5, and 6x6 spot sources in the fan-out demonstrated diffraction efficiency of 36%, 25%, 29%, 52%, and 49%, respectively, comparable with the theoretical values. This work shows the promising prospect of femtosecond laser fabrication in compatibly manufacturing various micro-optical devices including Dammann gratings and their integrated systems.

  12. Power loss characteristics of a sensing element based on a polymer optical fiber under cyclic tensile elongation.

    PubMed

    Chen, Yung-Chuan; Chen, Li-Wen; Lu, Wei-Hua

    2011-01-01

    In this study, power losses in polymer optical fiber (POF) subjected to cyclic tensile loadings are studied experimentally. The parameters discussed are the cyclic load level and the number of cycles. The results indicate that the power loss in POF specimens increases with increasing load level or number of cycles. The power loss can reach as high as 18.3% after 100 cyclic loadings. Based on the experimental results, a linear equation is proposed to estimate the relationship between the power loss and the number of cycles. The difference between the estimated results and the experimental results is found to be less than 3%.

  13. The impact of nanosilver addition on element ions release form light-cured dental composite and compomer into 0.9% NaCl.

    PubMed

    Sokołowski, Krzysztof; Szynkowska, Małgorzata I; Pawlaczyk, Aleksandra; Łukomska-Szymańska, Monika; Sokołowski, Jerzy

    2014-01-01

    The aim of this paper was to identify and to assess in semi-quantified way the release of different ions from composite and compomer restorative materials subjected to 0.9% NaCl solution, which simulates the environment of the human body. In the present study, the number of ions (Al, Ag, Ba, Sr, Ti) released from dental fillings over time (one week, one month and 3 months), in different temperatures (23°C, 37°C) and depending on the materials applied (unmodified/modified with nanosilver) was investigated. The results suggest that nanosilver addition influences directly on the process of metal ion releasing into 0.9% NaCl solution. The increase in the number of counts of metal ions was observed in the solutions in which samples modified with nanosilver were kept. Higher amount of metal ion release was observed for composite samples rather than for compomer materials. The study revealed that in general the number of released metal ions increases with the time of storage (for metal ions: Ti, Ba, Sr) and at higher temperature (Ag, Ti, Ba). Reverse tendency observed for silver ion release versus incubation time may be caused by the process of silver adsorption, which takes place on the surface of analyzed material and test-tube walls, where samples were incubated.

  14. Development of Genesis Solar Wind Sample Cleanliness Assessment: Initial Report on Sample 60341 Optical Imagery and Elemental Mapping

    NASA Technical Reports Server (NTRS)

    Gonzalez, C. P.; Goreva, Y. S.; Burnett, D. S.; Woolum, D.; Jurewicz, A. J.; Allton, J. H.; Rodriguez, P. J.; Burkett, P. J.

    2014-01-01

    Since 2005 the Genesis science team has experimented with techniques for removing the contaminant particles and films from the collection surface of the Genesis fragments. A subset of 40 samples have been designated as "cleaning matrix" samples. These are small samples to which various cleaning approaches are applied and then cleanliness is assessed optically, by TRXRF, SEM, ToF-SIMS, XPS, ellipsometry or other means [1-9]. Most of these sam-ples remain available for allocation, with cleanliness assessment data. This assessment allows evaluation of various cleaning techniques and handling or analytical effects. Cleaning techniques investigated by the Genesis community include acid/base etching, acetate replica peels, ion beam, and CO2 snow jet cleaning [10-16]. JSC provides surface cleaning using UV ozone exposure and ultra-pure water (UPW) [17-20]. The UPW rinse is commonly used to clean samples for handling debris between processing by different researchers. Optical microscopic images of the sample taken before and after UPW cleaning show what has been added or removed during the cleaning process.

  15. Four dimensional hybrid ultrasound and optoacoustic imaging via passive element optical excitation in a hand-held probe

    SciTech Connect

    Fehm, Thomas Felix; Razansky, Daniel; Deán-Ben, Xosé Luís

    2014-10-27

    Ultrasonography and optoacoustic imaging share powerful advantages related to the natural aptitude for real-time image rendering with high resolution, the hand-held operation, and lack of ionizing radiation. The two methods also possess very different yet highly complementary advantages of the mechanical and optical contrast in living tissues. Nonetheless, efficient integration of these modalities remains challenging owing to the fundamental differences in the underlying physical contrast, optimal signal acquisition, and image reconstruction approaches. We report on a method for hybrid acquisition and reconstruction of three-dimensional pulse-echo ultrasound and optoacoustic images in real time based on passive ultrasound generation with an optical absorber, thus avoiding the hardware complexity of active ultrasound generation. In this way, complete hybrid datasets are generated with a single laser interrogation pulse, resulting in simultaneous rendering of ultrasound and optoacoustic images at an unprecedented rate of 10 volumetric frames per second. Performance is subsequently showcased in phantom experiments and in-vivo measurements from a healthy human volunteer, confirming general clinical applicability of the method.

  16. Additive roles of PthAs in bacterial growth and pathogenicity associated with nucleotide polymorphisms in effector-binding elements of citrus canker susceptibility genes.

    PubMed

    Abe, Valeria Yukari; Benedetti, Celso Eduardo

    2016-10-01

    Citrus canker, caused by Xanthomonas citri, affects most commercial citrus varieties. All X. citri strains possess at least one transcription activator-like effector of the PthA family that activates host disease susceptibility (S) genes. The X. citri strain 306 encodes four PthA effectors; nevertheless, only PthA4 is known to elicit cankers on citrus. As none of the PthAs act as avirulence factors on citrus, we hypothesized that PthAs 1-3 might also contribute to pathogenicity on certain hosts. Here, we show that, although PthA4 is indispensable for canker formation in six Brazilian citrus varieties, PthAs 1 and 3 contribute to canker development in 'Pera' sweet orange, but not in 'Tahiti' lemon. Deletions in two or more pthA genes reduce bacterial growth in planta more pronouncedly than single deletions, suggesting an additive role of PthAs in pathogenicity and bacterial fitness. The contribution of PthAs 1 and 3 in canker formation in 'Pera' plants does not correlate with the activation of the canker S gene, LOB1 (LATERAL ORGAN BOUNDARIES 1), but with the induction of other PthA targets, including LOB2 and citrus dioxygenase (DIOX). LOB1, LOB2 and DIOX show differential PthA-dependent expression between 'Pera' and 'Tahiti' plants that appears to be associated with nucleotide polymorphisms found at or near PthA-binding sites. We also present evidence that LOB1 activation alone is not sufficient to elicit cankers on citrus, and that DIOX acts as a canker S gene in 'Pera', but not 'Tahiti', plants. Our results suggest that the activation of multiple S genes, such as LOB1 and DIOX, is necessary for full canker development.

  17. Restoring in-phase emissions from non-planar radiating elements using a transformation optics based lens

    NASA Astrophysics Data System (ADS)

    Yi, Jianjia; Burokur, Shah Nawaz; Piau, Gérard-Pascal; de Lustrac, André

    2015-07-01

    The broadband directive in-phase emission from an array of sources conformed cylindrically is numerically and experimentally reported. Such manipulation is achieved through the use of a lens designed by transformation optics concept. The all-dielectric lens prototype is realized through three-dimensional (3D) polyjet printing and presents a graded refractive index. A microstrip antenna array fabricated using standard lithography techniques and conformed on a cylindrical surface is used as TE-polarized wave launcher for the lens. To experimentally demonstrate the broadband focusing properties and in-phase directive emissions, both the far-field radiation patterns and the near-field distributions have been measured. Experimental measurements agreeing qualitatively with numerical simulations validate the proposed lens and open the way to inexpensive all-dielectric microwave lenses for beam forming and collimation.

  18. Restoring in-phase emissions from non-planar radiating elements using a transformation optics based lens

    SciTech Connect

    Yi, Jianjia; Burokur, Shah Nawaz Lustrac, André de; Piau, Gérard-Pascal

    2015-07-13

    The broadband directive in-phase emission from an array of sources conformed cylindrically is numerically and experimentally reported. Such manipulation is achieved through the use of a lens designed by transformation optics concept. The all-dielectric lens prototype is realized through three-dimensional (3D) polyjet printing and presents a graded refractive index. A microstrip antenna array fabricated using standard lithography techniques and conformed on a cylindrical surface is used as TE-polarized wave launcher for the lens. To experimentally demonstrate the broadband focusing properties and in-phase directive emissions, both the far-field radiation patterns and the near-field distributions have been measured. Experimental measurements agreeing qualitatively with numerical simulations validate the proposed lens and open the way to inexpensive all-dielectric microwave lenses for beam forming and collimation.

  19. Method and system for laser-based formation of micro-shapes in surfaces of optical elements

    DOEpatents

    Bass, Isaac Louis; Guss, Gabriel Mark

    2013-03-05

    A method of forming a surface feature extending into a sample includes providing a laser operable to emit an output beam and modulating the output beam to form a pulse train having a plurality of pulses. The method also includes a) directing the pulse train along an optical path intersecting an exposed portion of the sample at a position i and b) focusing a first portion of the plurality of pulses to impinge on the sample at the position i. Each of the plurality of pulses is characterized by a spot size at the sample. The method further includes c) ablating at least a portion of the sample at the position i to form a portion of the surface feature and d) incrementing counter i. The method includes e) repeating steps a) through d) to form the surface feature. The sample is free of a rim surrounding the surface feature.

  20. Three-dimensionally modulated anisotropic structure for diffractive optical elements created by one-step three-beam polarization holographic photoalignment

    NASA Astrophysics Data System (ADS)

    Kawai, Kotaro; Sakamoto, Moritsugu; Noda, Kohei; Sasaki, Tomoyuki; Kawatsuki, Nobuhiro; Ono, Hiroshi

    2016-03-01

    A diffractive optical element with a three-dimensional liquid crystal (LC) alignment structure for advanced control of polarized beams was fabricated by a highly efficient one-step photoalignment method. This study is of great significance because different two-dimensional continuous and complex alignment patterns can be produced on two alignment films by simultaneously irradiating an empty glass cell composed of two unaligned photocrosslinkable polymer LC films with three-beam polarized interference beam. The polarization azimuth, ellipticity, and rotation direction of the diffracted beams from the resultant LC grating widely varied depending on the two-dimensional diffracted position and the polarization states of the incident beams. These polarization diffraction properties are well explained by theoretical analysis based on Jones calculus.

  1. Wavelength-compensated color Fourier diffractive optical elements using a ferroelectric liquid crystal on silicon display and a color-filter wheel.

    PubMed

    Martínez, José Luis; Martínez-García, Antonio; Moreno, Ignacio

    2009-02-10

    In this work we describe the experimental realization of a simple scheme capable of implementing RGB improved dynamic color binary-phase Fourier computer-generated holograms (CGHs) by means of a single ferroelectric liquid crystal on silicon (FLCOS) display and an electronically controlled color-filter wheel. Tricolor multiwavelength illumination is achieved by aligning an Ar-Kr laser (wavelengths lambda(B)=488 nm and lambda(G)=568 nm) and a He-Ne laser ((R)=633 nm). Chromatic compensation is achieved by synchronizing a time sequence of properly scaled CGHs displayed on the FLCOS display with the corresponding filter from the color wheel. Quality CGHs are designed for each color component by using an optimized iterative Fourier transform algorithm applied to a phase-only modulation display. As a result, we present excellent experimental results on the reconstruction of these time-multiplexed wavelength-compensated diffractive optical elements and color CGHs.

  2. An adaptive spectral/DG method for a reduced phase-space based level set approach to geometrical optics on curved elements

    NASA Astrophysics Data System (ADS)

    Cockburn, Bernardo; Kao, Chiu-Yen; Reitich, Fernando

    2014-02-01

    We present an adaptive spectral/discontinuous Galerkin (DG) method on curved elements to simulate high-frequency wavefronts within a reduced phase-space formulation of geometrical optics. Following recent work, the approach is based on the use of level sets defined by functions satisfying the Liouville equations in reduced phase-space and, in particular, it relies on the smoothness of these functions to represent them by rapidly convergent spectral expansions in the phase variables. The resulting (hyperbolic) system of equations for the coefficients in these expansions are then amenable to a high-order accurate treatment via DG approximations. In the present work, we significantly expand on the applicability and efficiency of the approach by incorporating mechanisms that allow for its use in scattering simulations and for a reduced overall computational cost. With regards to the former we demonstrate that the incorporation of curved elements is necessary to attain any kind of accuracy in calculations that involve scattering off non-flat interfaces. With regards to efficiency, on the other hand, we also show that the level-set formulation allows for a space p-adaptive scheme that under-resolves the level-set functions away from the wavefront without incurring in a loss of accuracy in the approximation of its location. As we show, these improvements enable simulations that are beyond the capabilities of previous implementations of these numerical procedures.

  3. Neutron-capture element abundances in the planetary nebula NGC 5315 from deep high-resolution optical and near-IR spectrophotometry

    NASA Astrophysics Data System (ADS)

    Madonna, S.; García-Rojas, J.; Sterling, N. C.; Luridiana, V.

    2017-03-01

    We have done a spectroscopical analysis of the type I planetary nebula (PN) NGC 5315, through high-resolution (R ˜ 40000) optical spectroscopy with UVES at the 8.2m Very Large Telescope, and medium-resolution (R ˜ 4800) near-IR spectroscopy with FIRE at the 6.5m Magellan Baade telescope, covering a wide spectral range from 0.31 μm to 2.50μm. The main aim of this work is to investigate the slow neutron(n)-capture process (the s-process) in the Asymptotic Giant Branch (AGB) star progenitor of a type I PNe. We detected and identified about 700 features, including lines from the n-capture elements Kr, Se, and possibly Br and Xe. We compute physical conditions using line ratios of common ions. Ionic abundances are computed for the species with available atomic data. We calculate total abundances using recent ionization correction factors (ICFs) or by summing ionic abundances. Our results for common elements are in good agreement with previous works on the same object. We do not find a substantial s-process enrichment in NGC 5315, which is typical for type I PNe.

  4. New X-ray microprobe system for trace heavy element analysis using ultraprecise X-ray mirror optics of long working distance

    NASA Astrophysics Data System (ADS)

    Terada, Yasuko; Yumoto, Hirokatsu; Takeuchi, Akihisa; Suzuki, Yoshio; Yamauchi, Kazuto; Uruga, Tomoya

    2010-05-01

    A new X-ray microprobe system for trace heavy element analysis using ultraprecise X-ray mirror optics of 300 mm long working distance has been developed at beamline 37XU of SPring-8. A focusing test has been performed in the X-ray energy range 20-37.7 keV. A focused beam size of 1.3 μm ( V)×1.5 μm ( H) has been achieved at an X-ray energy of 30 keV, and a total photon flux of the focused beam was about 2.7×10 10 photons/s. Micro-X-ray fluorescence (μ-XRF) analysis of eggplant roots has been carried out using the developed microprobe. It is clearly observed in the XRF images that cadmium is highly accumulated in the endodermis, exodermis and epidermis of roots. This study demonstrates the potential of scanning microscopy for heavy elements analysis in the high-energy X-ray region.

  5. A methodology for quantifying trace elements in the exoskeletons of Florida stone crab (Menippe mercenaria) larvae using inductively coupled plasma optical emission spectrometry (ICP–OES)

    USGS Publications Warehouse

    Gravinese, Philip M.; Flannery, Jennifer A.; Toth, Lauren T.

    2016-11-23

    The larvae of the Florida stone crab, Menippe mercenaria, migrate through a variety of habitats as they develop and, therefore, experience a broad range of environmental conditions through ontogeny. Environmental variability experienced by the larvae may result in distinct elemental signatures within the exoskeletons, which could provide a tool for tracking the environmental history of larval stone crab populations. A method was developed to examine trace-element ratios, specifically magnesium-to-calcium (Mg/Ca) and strontium-to-calcium (Sr/Ca) ratios, in the exoskeletons of M. mercenaria larvae. Two developmental stages of stone crab larvae were analyzed—stage III and stage V. Specimens were reared in a laboratory environment under stable conditions to quantify the average ratios of Mg/Ca and Sr/Ca of larval stone crab exoskeletons and to determine if the ratios differed through ontogeny. The elemental compositions (Ca, Mg, and Sr) in samples of stage III larvae (n = 50 per sample) from 11 different broods (mean Sr/Ca = 5.916 ± 0.161 millimole per mole [mmol mol−1]; mean Mg/Ca = 218.275 ± 59.957 mmol mol−1) and stage V larvae (n = 10 per sample) from 12 different broods (mean Sr/Ca = 6.110 ± 0.300 mmol mol−1; mean Mg/Ca = 267.081 ± 67.211 mmol mol–1) were measured using inductively coupled plasma optical emission spectrometry (ICP–OES). The ratio of Sr/Ca significantly increased from stage III to stage V larvae, suggesting an ontogenic shift in Sr/Ca ratios between larval stages. The ratio of Mg/Ca did not change significantly between larval stages, but variability among broods was high. The method used to examine the trace-element ratios provided robust, highly reproducible estimates of Sr/Ca and Mg/Ca ratios in the larvae of M. mercenaria, demonstrating that ICP–OES can be used to determine the trace-element composition of chitinous organisms like the Florida stone crab.

  6. Elemental profiling and geographical differentiation of Ethiopian coffee samples through inductively coupled plasma-optical emission spectroscopy (ICP-OES), ICP-mass spectrometry (ICP-MS) and direct mercury analyzer (DMA).

    PubMed

    Habte, Girum; Hwang, In Min; Kim, Jae Sung; Hong, Joon Ho; Hong, Young Sin; Choi, Ji Yeon; Nho, Eun Yeong; Jamila, Nargis; Khan, Naeem; Kim, Kyong Su

    2016-12-01

    This study was aimed to establish the elemental profiling and provenance of coffee samples collected from eleven major coffee producing regions of Ethiopia. A total of 129 samples were analyzed for forty-five elements using inductively coupled plasma (ICP)-optical emission spectroscopy (OES), ICP-mass spectrometry (MS) and direct mercury analyzer (DMA). Among the macro elements, K showed the highest levels whereas Fe was found to have the lowest concentration values. In all the samples, Ca, K, Mg, P and S contents were statistically significant (p<0.05). Micro elements showed the concentrations order of: Mn>Cu>Sr>Zn>Rb>Ni>B. Contents of the trace elements were lower than the permissible standard values. Inter-regions differentiation by cluster analysis (CA), linear discriminant analysis (LDA) and principal component analysis (PCA) showed that micro and trace elements are the best chemical descriptors of the analyzed coffee samples.

  7. Effect of Te addition into As{sub 2}Se{sub 3} thin film: Optical property study by FTIR and XPS

    SciTech Connect

    Panda, Tribikram; Naik, R.; Chinnaiyah, S.; Ganesan, R.

    2015-06-24

    In the present work, we report the effect of Te deposition onto As{sub 2}Se{sub 3} film which affects the optical properties. The Te/As{sub 2}Se{sub 3} film was illuminated with 532 nm laser to study the photo induced diffusion. The prepared As{sub 2}Se{sub 3}, Te/As{sub 2}Se{sub 3} films were characterized by X-ray diffraction which show a completely amorphous nature. On the basis of optical transmission data carried out by Fourier Transform infrared Spectroscopy, a non direct transition was found for these films. The optical bandgap is found to be decreased with Te deposition and photo darkening phenomena is observed for the diffused film. The change in the optical constants are also supported by the corresponding change in different types of bonds which are being analyzed by X-ray photoelectron spectroscopy.

  8. Polyhedral integrated and free space optical interconnection

    DOEpatents

    Erteza, Ireena A.

    1998-01-01

    An optical communication system uses holographic optical elements to provide guided wave and non-guided communication, resulting in high bandwidth, high connectivity optical communications. Holograms within holographic optical elements route optical signals between elements and between nodes connected to elements. Angular and wavelength multiplexing allow the elements to provide high connectivity. The combination of guided and non-guided communication allows compact polyhedral system geometries. Guided wave communications provided by multiplexed substrate-mode holographic optical elements eases system alignment.

  9. Polyhedral integrated and free space optical interconnection

    DOEpatents

    Erteza, I.A.

    1998-01-06

    An optical communication system uses holographic optical elements to provide guided wave and non-guided communication, resulting in high bandwidth, high connectivity optical communications. Holograms within holographic optical elements route optical signals between elements and between nodes connected to elements. Angular and wavelength multiplexing allow the elements to provide high connectivity. The combination of guided and non-guided communication allows compact polyhedral system geometries. Guided wave communications provided by multiplexed substrate-mode holographic optical elements eases system alignment. 7 figs.

  10. Microstructural effects on fracture behavior of particulate composites: Investigation of toughening mechanisms using optical and boundary element methods

    NASA Astrophysics Data System (ADS)

    Kitey, Rajesh

    Particulate polymer composites are used in a variety of engineering applications. These are generally two phase materials with polymeric phase reinforced by a filler phase to improve overall mechanical, thermal and/or dielectric functionalities. From a mechanical perspective, polymers when filled with stiffer particulates generally show enhanced elastic properties and creep resistance. Achieving similar improvement in failure characteristics has not been consistent due to a lack of thorough understanding of microstructural and loading rate effects. This dissertation addresses a few of these issues by studying effects of filler particle size, filler size distribution and filler-matrix adhesion strength on fracture behavior under quasi-static and dynamic loading conditions. Glass-filled epoxy composites consisting of solid spherical particles are studied in this research. Spherical particles of mean dia. (D) 7 mum to 200 mum are used to reinforce epoxy matrix at a constant volume fraction (Vf = 10%) and two different filler-matrix strengths, weak and strong. Optical interferometry in conjunction with high-speed photography is used to quantify crack growth and deformation histories during impact loading. Although elastic characteristics remain unaffected by microstructural variations, significant differences in fracture behaviors are seen. Both weakly and strongly bonded particles in the matrix show higher values of steady-state dynamic fracture toughness, KIss, relative to unfilled material. Filler particle size affects KIss significantly when particles are weakly bonded to the matrix but not when bonded strongly. Weakly bonded fillers result in consistently higher KIss values compared to strongly bonded counterparts. A particle size of 35 mum appears to be the optimum at the chosen Vf. The KIss of two inter-mixed particle sizes (each of 5% Vf) is bounded by the KIss values of the composite with corresponding single particle size. Fracture surface micromeasurements

  11. Tuned electronic, optical and mechanical properties of pristine and hetero nanotubes of group IV elements (C, Si and Ge)

    NASA Astrophysics Data System (ADS)

    Chandel, Surjeet Kumar; Kumar, Arun; Sharma, Raman; Ahluwalia, P. K.

    2015-09-01

    Density functional theory has been used to investigate the structural, electronic, optical and mechanical properties of pristine nanotubes of carbon, silicon, germanium and their hetero nanotubes having armchair conformation with chirality (6,6). In the pristine nanotubes it is found that the cohesive energy per atom is more for CNT as compared to other nanotubes under investigation. However, in hetero systems under study its value is highest for SiCNT system and least for GeCNT. GeNT and SiGeNT have been observed to be more puckered in comparison to other systems. All the pristine and heteronanotubes in our study are found to be semiconducting in nature, except GeNT, which is found to be metallic in nature with a conductance of 2G0, indicating GeNT to be an ideal material for ballistic transport. Three different types of hetero nanotubes have wide band gap spectrum which opens up an arena for band gap selective engineered devices. The band gap for SiCNT and GeCNT lie in the visible region, while the band gap for other systems lie in the infrared region. The tuning of electronic band structure by means of compression, tensile strain and external electric field indicates that the band gap can be altered considerably. There is a band gap closure under both compression and expansion at a certain value in all the cases except SiCNT, revealing that its band gap can be varied considerably. The decreasing order of tensile strength is CNT > SiCNT > GeCNT > SiNT > GeNT > SiGeNT. The effective mass of holes decreases for pristine systems on the application of compression. Under no strain the effective mass of electrons is generally found to be larger than holes in hetero systems, while it is reverse in pristine systems. In case of unstrained systems, we generally observed that the more the effective mass of electron, the more is the band gap in the corresponding system. Electronic band structure and corresponding total and partial DOS for pristine and heteronanotubes. In the

  12. Modular optical detector system

    DOEpatents

    Horn, Brent A.; Renzi, Ronald F.

    2006-02-14

    A modular optical detector system. The detector system is designed to detect the presence of molecules or molecular species by inducing fluorescence with exciting radiation and detecting the emitted fluorescence. Because the system is capable of accurately detecting and measuring picomolar concentrations it is ideally suited for use with microchemical analysis systems generally and capillary chromatographic systems in particular. By employing a modular design, the detector system provides both the ability to replace various elements of the detector system without requiring extensive realignment or recalibration of the components as well as minimal user interaction with the system. In addition, the modular concept provides for the use and addition of a wide variety of components, including optical elements (lenses and filters), light sources, and detection means, to fit particular needs.

  13. Optical properties, morphology and elemental chemical composition of atmospheric particles at T1 supersite on MILAGRO campaign

    NASA Astrophysics Data System (ADS)

    Carabali, G.; Mamani-Paco, R.; Castro, T.; Peralta, O.; Herrera, E.; Trujillo, B.

    2011-05-01

    Atmospheric particles were sampled at T1 supersite (19°43' N latitude, 98°58' W longitude, and 2340 m above sea level) during MILAGRO campaign. T1 was located at the north of Mexico City Metropolitan Area (MCMA). Aerosol sampling was done by placing transmission electron microscope (TEM) copper grids on the last 5 stages of an 8-stage MOUDI cascade impactor (d50 = 1.8, 1.0, 0.56, 0.32, and 0.18 μm). Samples were obtained at morning (06:00-09:00), noon (11:00-14:00), afternoon (16:00-19:00) and evening (21:00-24:00) local time. Absorption and scattering coefficients, and particles concentration (0.01-3 μm aerodynamic diameter) were measured simultaneously using a PASP absorption photometer (operated at 550 nm), a portable integrating nephelometer (at 530 nm) and a CNI particle counter. TEM images of particles were acquired at different magnifications using a CM 200 Phillips TEM-EDAX system. The morphology of atmospheric particles for two aerodynamic diameters (0.18 and 1.8 μm) was compared using border-based fractal dimension. Particles sampled under Mexico City pollution influence showed not much variability, suggesting the presence of more compact particles in smaller sizes (d50 = 1.8 μm) at the site. The presence of higher numbers of compact particles can be attributed to aerosol aging and secondary aerosol formation, among others. Under early morning conditions, smaller particles (d50 = 0.18 μm) had more irregular features resulting in a higher average fractal dimension. Energy dispersive X-ray spectroscopy (EDS) was used to determine the elemental composition of particles. EDS analysis in particles with d50 = 0.18 μm showed a higher content of carbonaceous material and relevant amounts of Si, Fe, K, and Co. This may indicate an impact from industrial and vehicle's emissions on atmospheric particles.

  14. Comparison Between Elemental Carbon Measured Using Thermal-Optical Analysis and Black Carbon Measurements Using A Novel Cellphone-Based System

    NASA Astrophysics Data System (ADS)

    Ramanathan, N.; Khan, B.; Leong, I.; Lukac, M.

    2011-12-01

    Black carbon (BC) is produced through the incomplete combustion of fossil and solid fuels. Current BC emissions inventories have large uncertainties of factors of 2 or more due to sparse measurements and because BC is often emitted by local sources that vary over time and space (Bond et al, 2004). Those uncertainties are major sources of error in air pollution models. Emissions from a variety of improved cookstove/fuel/combustion conditions were collected on pre-conditioned 47 mm quartz-fiber filters and analyzed for organic carbon (OC) and elemental carbon (EC) using thermal-optical analysis (TOA). The samples were then analyzed for BC concentration by using cellphone-based instrumentation developed by Ramanathan et al., 2011. The cellphone-based monitoring system (CBMS) is a wireless, low-cost, low-power system that monitors BC emissions. The CBMS is comprised of an aerosol filter sampler containing a battery-powered air pump and a 25mm filter holder that draws air in through a quartz-fiber filter. As black carbon deposits increase, the filter darkens--the darkest color representing the highest loading. A cellphone photograph of the filter with the black carbon deposit is taken and relayed to an analytics unit for comparison to a reference scale to estimate airborne BC concentration. The BC concentration can then be compared to the thermally derived EC concentration. TOA was conducted on a Sunset Laboratory Dual Optics Carbon Analyzer using a modified version of the Birch and Cary (1996) NIOSH 5040 protocol. The dual-optical instrument permitted simultaneous monitoring of the transmission (TOT) and reflectance (TOR). 619 samples were collected; EC was obtained using NIOSH TOT and NIOSH TOR methods, and BC was obtained using the CBMS analytics unit. The mean BC value reported by the CBMS agrees within 20% of the reference values for EC, confirming the findings in Ramanathan et al. (2011) based on samples from India. Given this accuracy, we conclude that the CBMS

  15. Diffractive optical elements designed for highly precise far-field generation in the presence of artifacts typical for pixelated spatial light modulators

    NASA Astrophysics Data System (ADS)

    Milewski, Gabriel; Engström, David; Bengtsson, Jörgen

    2007-01-01

    Diffractive optical elements (DOEs) realized by spatial light modulators (SLMs) often have features that distinguish them from most conventional, static DOEs: strong coupling between phase and amplitude modulation, a modulation versus steering parameter characteristic that may not be precisely known (and may vary with, e.g., temperature), and deadspace effects and interpixel cross talk. For an optimal function of the DOE, e.g. as a multiple-beam splitter, the DOE design must account for these artifacts. We present an iterative design method in which the optimal setting of each SLM pixel is carefully chosen by considering the SLM artifacts and the design targets. For instance, the deadspace-interpixel effects are modeled by dividing the pixel to be optimized, and its nearest neighbors, into a number of subareas, each with its unique response and far-field contribution. Besides the customary intensity control, the design targets can also include phase control of the optical field in one or more of the beams in the beam splitter. We show how this can be used to cancel a strong unwanted zeroth-order beam, which results from using a slightly incorrect modulation characteristic for the SLM, by purposely sending a beam in the same direction but with the opposite phase. All the designs have been implemented on the 256 × 256 central pixels of a reflective liquid crystal on silicon SLM with a selected input polarization state and a direction of transmission axis of the output polarizer such that for the available different pixel settings a phase modulation of ˜2π rad could be obtained, accompanied by an intensity modulation depth as high as >95%.

  16. Ring-laser gyroscope system using dispersive element(s)

    NASA Technical Reports Server (NTRS)

    Smith, David D. (Inventor)

    2010-01-01

    A ring-laser gyroscope system includes a ring-laser gyroscope (RLG) and at least one dispersive element optically coupled to the RLG's ring-shaped optical path. Each dispersive element has a resonant frequency that is approximately equal to the RLG's lasing frequency. A group index of refraction defined collectively by the dispersive element(s) has (i) a real portion that is greater than zero and less than one, and (ii) an imaginary portion that is less than zero.

  17. In situ sulfur isotopes (δ(34)S and δ(33)S) analyses in sulfides and elemental sulfur using high sensitivity cones combined with the addition of nitrogen by laser ablation MC-ICP-MS.

    PubMed

    Fu, Jiali; Hu, Zhaochu; Zhang, Wen; Yang, Lu; Liu, Yongsheng; Li, Ming; Zong, Keqing; Gao, Shan; Hu, Shenghong

    2016-03-10

    The sulfur isotope is an important geochemical tracer in diverse fields of geosciences. In this study, the effects of three different cone combinations with the addition of N2 on the performance of in situ S isotope analyses were investigated in detail. The signal intensities of S isotopes were improved by a factor of 2.3 and 3.6 using the X skimmer cone combined with the standard sample cone or the Jet sample cone, respectively, compared with the standard arrangement (H skimmer cone combined with the standard sample cone). This signal enhancement is important for the improvement of the precision and accuracy of in situ S isotope analysis at high spatial resolution. Different cone combinations have a significant effect on the mass bias and mass bias stability for S isotopes. Poor precisions of S isotope ratios were obtained using the Jet and X cones combination at their corresponding optimum makeup gas flow when using Ar plasma only. The addition of 4-8 ml min(-1) nitrogen to the central gas flow in laser ablation MC-ICP-MS was found to significantly enlarge the mass bias stability zone at their corresponding optimum makeup gas flow in these three different cone combinations. The polyatomic interferences of OO, SH, OOH were also significantly reduced, and the interference free plateaus of sulfur isotopes became broader and flatter in the nitrogen mode (N2 = 4 ml min(-1)). However, the signal intensity of S was not increased by the addition of nitrogen in this study. The laser fluence and ablation mode had significant effects on sulfur isotope fractionation during the analysis of sulfides and elemental sulfur by laser ablation MC-ICP-MS. The matrix effect among different sulfides and elemental sulfur was observed, but could be significantly reduced by line scan ablation in preference to single spot ablation under the optimized fluence. It is recommended that the d90 values of the particles in pressed powder pellets for accurate and precise S isotope analysis

  18. Optical Firmware

    NASA Technical Reports Server (NTRS)

    Bergman, Larry A.

    1989-01-01

    Data-processing system exploits high speeds inherent in optical elements. Instruction sets for different computer operations reside on different external memory chips. Laser diodes activated for each operation generate light, reflected by holographic optical element to designated receptors in arithmetic and logic unit. Pattern of light beams embodies instruction set at given instant. With potential ability to reprogram in real time, conceptual system applicable to task-driven programming or artificial intelligence.

  19. Element-specific magnetization reversal in Fe/Ce multilayers:. a study by X-ray magnetic circular dichroism and the magneto-optic Kerr effect

    NASA Astrophysics Data System (ADS)

    Münzenberg, M.; Arend, M.; Felsch, W.; Pizzini, S.; Fontaine, A.; Neisius, T.; Pascarelli, S.

    2000-10-01

    Fe/Ce multilayers are magnetically soft with coercive fields of a few Oersteds. In this artificial system, the itinerant 5d electrons of Ce are magnetically polarized by hybridization with the spin-split 3d states of Fe. To obtain an insight into the magnetization reversal process, the element selectivity of X-ray magnetic circular dichroism was used to measure the magnetization of the Ce-5d electrons as a function of an applied magnetic field. Comparison with the magnetization curves studied by the magneto-optic Kerr effect, which averages over the whole system, revealed that the coercivity in the hysteresis of the ordered Ce-5d moments is reduced by 50%. We propose that this is an effect of the magnetically disturbed interface or of the complex non-collinear magnetic structure of the Ce layers detected by recent experiments of X-ray resonant magnetic scattering. The results are compared to the X-ray dichroic and Kerr hysteresis loops of the multilayers Fe/La/Ce/La and Fe/CeH 2- δ. These systems are magnetically harder and their coercivities are identical.

  20. Finite element analysis on the electrical and optical properties in HTL/mCP/ETL multilayer organic light emitting diode device structure.

    PubMed

    Hwang, Young Wook; Won, Tae Young

    2014-08-01

    In this paper, we report our numerical study on the electrical and optical properties in HTL/mCP/ETL multilayer organic light emitting diode (OLED) device structure. Our finite element method (FEM) model includes the transport behavior of electrons and holes, the generation and decay of excitons, and emission and extinction properties of excitons. We employ the multilayer structure which consists of 1,1-bis[(di-4-tolylamino)phenyl] cyclohexane (TAPC); 4,4'-bis[N-(1-naphthyl)-N-phenyl-amino]biphenyl (α-NPD); 4,4'-bis[N-(p-tolyl)-N-phenylamino] biphenyl (TPD); 3,5'-N,N'-dicarbazole-benzene (mCP); 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP); 4,7-diphenyl-1, 10-phenanthroline (BPhen). We report our observation of the effect of the different hole transport layer following TAPC, α-NPD, TPD and also discuss the effect of different electron transport layer following BCP, BPhen. Our simulation revealed that the charge balance results in a significant effect on the recombination density which is related to the generation of excitons.