Science.gov

Sample records for laser light diffraction

  1. Diffraction rings obtained from a suspension of skeletal myofibrils by laser light illumination. Study of internal structure of sarcomeres.

    PubMed Central

    Ishiwata, S; Okamura, N

    1989-01-01

    Diffraction rings corresponding to the first, second, and third order were obtained by laser light illumination from a suspension of rabbit glycerinated psoas myofibrils (diameter, 1-2 microns; average length of the straight region, 44 microns; average sarcomere length, 2.2-2.6 microns) of which the optical thickness was appropriately chosen. Dispersed myofibrils were nearly randomly oriented in two dimensions, so that the effects of muscle volume were minimized; these effects usually interfere significantly with a quantitative analysis of laser optical diffraction in the fiber system. The diameters of diffraction rings represented the average sarcomere length. By using this system, we confirmed the ability of the unit cell (sarcomere) structure model to explain the intensity change of diffraction lines accompanying the dissociation from both ends of thick filaments in a high salt solution. The length of an A-band estimated from the relative intensity of diffraction rings and that directly measured on phase-contrast micrographs coincided well with each other. Also, we found that myofibrils with a long sarcomere length shorten to a slack length accompanying the decrease in overlap between thick and thin filaments produced by the dissociation of thick filaments. Images FIGURE 4 FIGURE 1 FIGURE 8 PMID:2692720

  2. Laser light routing in an elongated micromachined vapor cell with diffraction gratings for atomic clock applications.

    PubMed

    Chutani, Ravinder; Maurice, Vincent; Passilly, Nicolas; Gorecki, Christophe; Boudot, Rodolphe; Abdel Hafiz, Moustafa; Abbé, Philippe; Galliou, Serge; Rauch, Jean-Yves; de Clercq, Emeric

    2015-09-14

    This paper reports on an original architecture of microfabricated alkali vapor cell designed for miniature atomic clocks. The cell combines diffraction gratings with anisotropically etched single-crystalline silicon sidewalls to route a normally-incident beam in a cavity oriented along the substrate plane. Gratings have been specifically designed to diffract circularly polarized light in the first order, the latter having an angle of diffraction matching the (111) sidewalls orientation. Then, the length of the cavity where light interacts with alkali atoms can be extended. We demonstrate that a longer cell allows to reduce the beam diameter, while preserving the clock performances. As the cavity depth and the beam diameter are reduced, collimation can be performed in a tighter space. This solution relaxes the constraints on the device packaging and is suitable for wafer-level assembly. Several cells have been fabricated and characterized in a clock setup using coherent population trapping spectroscopy. The measured signals exhibit null power linewidths down to 2.23 kHz and high transmission contrasts up to 17%. A high contrast-to-linewidth ratio is found at a linewidth of 4.17 kHz and a contrast of 5.2% in a 7-mm-long cell despite a beam diameter reduced to 600 μm.

  3. Laser light routing in an elongated micromachined vapor cell with diffraction gratings for atomic clock applications

    PubMed Central

    Chutani, Ravinder; Maurice, Vincent; Passilly, Nicolas; Gorecki, Christophe; Boudot, Rodolphe; Abdel Hafiz, Moustafa; Abbé, Philippe; Galliou, Serge; Rauch, Jean-Yves; de Clercq, Emeric

    2015-01-01

    This paper reports on an original architecture of microfabricated alkali vapor cell designed for miniature atomic clocks. The cell combines diffraction gratings with anisotropically etched single-crystalline silicon sidewalls to route a normally-incident beam in a cavity oriented along the substrate plane. Gratings have been specifically designed to diffract circularly polarized light in the first order, the latter having an angle of diffraction matching the (111) sidewalls orientation. Then, the length of the cavity where light interacts with alkali atoms can be extended. We demonstrate that a longer cell allows to reduce the beam diameter, while preserving the clock performances. As the cavity depth and the beam diameter are reduced, collimation can be performed in a tighter space. This solution relaxes the constraints on the device packaging and is suitable for wafer-level assembly. Several cells have been fabricated and characterized in a clock setup using coherent population trapping spectroscopy. The measured signals exhibit null power linewidths down to 2.23 kHz and high transmission contrasts up to 17%. A high contrast-to-linewidth ratio is found at a linewidth of 4.17 kHz and a contrast of 5.2% in a 7-mm-long cell despite a beam diameter reduced to 600 μm. PMID:26365754

  4. Laser light routing in an elongated micromachined vapor cell with diffraction gratings for atomic clock applications

    NASA Astrophysics Data System (ADS)

    Chutani, Ravinder; Maurice, Vincent; Passilly, Nicolas; Gorecki, Christophe; Boudot, Rodolphe; Abdel Hafiz, Moustafa; Abbé, Philippe; Galliou, Serge; Rauch, Jean-Yves; de Clercq, Emeric

    2015-09-01

    This paper reports on an original architecture of microfabricated alkali vapor cell designed for miniature atomic clocks. The cell combines diffraction gratings with anisotropically etched single-crystalline silicon sidewalls to route a normally-incident beam in a cavity oriented along the substrate plane. Gratings have been specifically designed to diffract circularly polarized light in the first order, the latter having an angle of diffraction matching the (111) sidewalls orientation. Then, the length of the cavity where light interacts with alkali atoms can be extended. We demonstrate that a longer cell allows to reduce the beam diameter, while preserving the clock performances. As the cavity depth and the beam diameter are reduced, collimation can be performed in a tighter space. This solution relaxes the constraints on the device packaging and is suitable for wafer-level assembly. Several cells have been fabricated and characterized in a clock setup using coherent population trapping spectroscopy. The measured signals exhibit null power linewidths down to 2.23 kHz and high transmission contrasts up to 17%. A high contrast-to-linewidth ratio is found at a linewidth of 4.17 kHz and a contrast of 5.2% in a 7-mm-long cell despite a beam diameter reduced to 600 μm.

  5. Laser light routing in an elongated micromachined vapor cell with diffraction gratings for atomic clock applications.

    PubMed

    Chutani, Ravinder; Maurice, Vincent; Passilly, Nicolas; Gorecki, Christophe; Boudot, Rodolphe; Abdel Hafiz, Moustafa; Abbé, Philippe; Galliou, Serge; Rauch, Jean-Yves; de Clercq, Emeric

    2015-01-01

    This paper reports on an original architecture of microfabricated alkali vapor cell designed for miniature atomic clocks. The cell combines diffraction gratings with anisotropically etched single-crystalline silicon sidewalls to route a normally-incident beam in a cavity oriented along the substrate plane. Gratings have been specifically designed to diffract circularly polarized light in the first order, the latter having an angle of diffraction matching the (111) sidewalls orientation. Then, the length of the cavity where light interacts with alkali atoms can be extended. We demonstrate that a longer cell allows to reduce the beam diameter, while preserving the clock performances. As the cavity depth and the beam diameter are reduced, collimation can be performed in a tighter space. This solution relaxes the constraints on the device packaging and is suitable for wafer-level assembly. Several cells have been fabricated and characterized in a clock setup using coherent population trapping spectroscopy. The measured signals exhibit null power linewidths down to 2.23 kHz and high transmission contrasts up to 17%. A high contrast-to-linewidth ratio is found at a linewidth of 4.17 kHz and a contrast of 5.2% in a 7-mm-long cell despite a beam diameter reduced to 600 μm. PMID:26365754

  6. Diffraction of a Laser Beam.

    ERIC Educational Resources Information Center

    Jodoin, Ronald E.

    1979-01-01

    Investigates the effect of the nonuniform irradiance across a laser beam on diffraction of the beam, specifically the Fraunhofer diffraction of a laser beam with a Gaussian irradiance profile as it passes through a circular aperture. (GA)

  7. Fraunhofer diffraction of light by human enamel.

    PubMed

    O'Brien, W J

    1988-02-01

    Fraunhofer diffraction patterns of human enamel samples were photographed with a helium-neon laser beam (lambda = 633 nm). The first-order diffraction angle was in reasonable agreement with a prediction based upon enamel prisms acting as a two-dimensional grating. These results support the hypothesis that enamel diffracts light because of the periodic structure of enamel prisms with interprismatic spaces, which act as slits.

  8. CONTROLLING THE CHARACTERISTICS OF LASER LIGHT: Correlation of quantum intensity fluctuations in Raman-Nath diffraction

    NASA Astrophysics Data System (ADS)

    Alodzhants, A. P.; Arakelyan, S. M.; Kryukchan, G. Yu

    1993-07-01

    A new method of generating correlated fluctuations in optical fields, based on Raman-Nath diffraction by a fine grating, is discussed. A nonclassical effect is predicted: a suppression of quantum fluctuations below the level of full coherence in the sum or difference photon numbers for the transmitted and scattered waves. The physics of this phenomenon involves a correlation of quantum fluctuations in the intensities of two modes that are coupled nonlinearly. This correlation is most effective in the limit of parametric interaction between the waves in the medium.

  9. Generation of 3.5 W of diffraction-limited green light from SHG of a single tapered diode laser in a cascade of nonlinear crystals

    NASA Astrophysics Data System (ADS)

    Hansen, Anders K.; Jensen, Ole B.; Sumpf, Bernd; Erbert, Götz; Unterhuber, Angelika; Drexler, Wolfgang; Andersen, Peter E.; Petersen, Paul Michael

    2014-02-01

    Many applications, e.g., within biomedicine stand to benefit greatly from the development of diode laser-based multi- Watt efficient compact green laser sources. The low power of existing diode lasers in the green area (about 100 mW) means that the most promising approach remains nonlinear frequency conversion of infrared tapered diode lasers. Here, we describe the generation of 3.5 W of diffraction-limited green light from SHG of a single tapered diode laser, itself yielding 10 W at 1063 nm. This SHG is performed in single pass through a cascade of two PPMgO:LN crystals with re-focusing and dispersion compensating optics between the two nonlinear crystals. In the low-power limit, such a cascade of two crystals has the theoretical potential for generation of four times as much power as a single crystal without adding significantly to the complexity of the system. The experimentally achieved power of 3.5 W corresponds to a power enhancement greater than 2 compared to SHG in each of the crystals individually and is the highest visible output power generated by frequency conversion of a single diode laser. Such laser sources provide the necessary pump power for biophotonics applications, such as optical coherence tomography or multimodal imaging devices, e.g., FTCARS-OCT, based on a strongly pumped ultrafast Ti:Sapphire laser.

  10. A comparative study of ultrasound and laser light diffraction techniques for particle size determination in dairy beverages

    NASA Astrophysics Data System (ADS)

    Meyer, S.; Berrut, S.; Goodenough, T. I. J.; Rajendram, V. S.; Pinfield, V. J.; Povey, M. J. W.

    2006-02-01

    The particle size distribution (PSD) of milkfat droplets of raw and homogenized milk was determined by a diagnostic ultrasound technique that was initially calibrated with colloidal silica. The quality of the fit between ultrasound theory and experiment is discussed and provides a basis for comparison with the reference laser light scattering technique. The predicted ultrasonic attenuation was determined from the ECAH (Epstein P S and Carhart R R 1953 J. Acoust. Soc. Am. 25 553-65, Allegra J R and Hawley S A 1972 J. Acoust. Soc. Am. 51 1545-64) model using thermophysical data for milkfat and milk serum. New thermophysical properties of milkfat were established. The experimental data were obtained with the Ultrasizer spectrometer. Both techniques were affected by the milk proteins and could provide only qualitative milkfat PSD for the raw and the homogenized milk samples. Therefore, they showed their limitations to characterize multiple emulsions. However, preliminary results are shown for the ultrasound technique that account for the impact of the protein on the measured data and hence obtain quantitative results for the milkfat size distributions.

  11. Tailoring non-diffractive beams from amorphous light speckles

    NASA Astrophysics Data System (ADS)

    Di Battista, D.; Ancora, D.; Leonetti, M.; Zacharakis, G.

    2016-09-01

    Bessel beams are non-diffracting light structures, which maintain their spatial features after meters of propagation and are realized with simple optical elements such as axicon lenses, spatial filters, and lasers. In this paper, we demonstrate a method for generating non diffractive Bessel-like beams through a heavily scattering system, exploiting wavefronts shaped by a spatial light modulator. With the proposed method starting from amorphous speckle patterns, it is possible to produce at user defined positions configurable and non-diffracting light distributions which can improve depth-of-field in speckled illumination microscopy.

  12. Electron Diffraction Experiments using Laser Plasma Electrons

    SciTech Connect

    Fill, E E; Trushin, S; Tommasini, R; Bruch, R

    2005-09-07

    We demonstrate that electrons emitted from a laser plasma can be used to generate diffraction patterns in reflection and transmission. The electrons are emitted in the direction of laser polarization with energies up to 100 keV. The broad electron energy spectrum makes possible the generation of a ''streaked'' diffraction pattern which allows recording fast processes in a single run.

  13. Remote Laser Diffraction PSD Analyzer

    SciTech Connect

    T. A. Batcheller; G. M. Huestis; S. M. Bolton

    2000-06-01

    Particle size distribution (PSD) analysis of radioactive slurry samples were obtained using a modified off-the-shelf classical laser light scattering particle size analyzer. A Horiba Instruments Inc. Model La-300 PSD analyzer, which has a 0.1 to 600 micron measurement range, was modified for remote application in a hot cell (gamma radiation) environment. The general details of the modifications to this analyzer are presented in this paper. This technology provides rapid and simple PSD analysis, especially down in the fine and microscopic particle size regime. Particle size analysis of these radioactive slurries down in this smaller range was not achievable - making this technology far superior than the traditional methods used previously. Remote deployment and utilization of this technology is in an exploratory stage. The risk of malfunction in this radiation environment is countered by gaining of this tremendously useful fundamental engineering data. Successful acquisition of this data, in conjunction with other characterization analyses, provides important information that can be used in the myriad of potential radioactive waste management alternatives.

  14. Remote Laser Diffraction PSD Analyzer

    SciTech Connect

    Batcheller, Thomas Aquinas; Huestis, Gary Michael; Bolton, Steven Michael

    2000-06-01

    Particle size distribution (PSD) analysis of radioactive slurry samples were obtained using a modified "off-the-shelf" classical laser light scattering particle size analyzer. A Horiba Instruments Inc. Model La-300 PSD analyzer, which has a 0.1 to 600 micron measurement range, was modified for remote application in a "hot cell" (gamma radiation) environment. The general details of the modifications to this analyzer are presented in this paper. This technology provides rapid and simple PSD analysis, especially down in the fine and microscopic particle size regime. Particle size analysis of these radioactive slurries down in this smaller range was not achievable - making this technology far superior than the traditional methods used previously. Remote deployment and utilization of this technology is in an exploratory stage. The risk of malfunction in this radiation environment is countered by gaining of this tremendously useful fundamental engineering data. Successful acquisition of this data, in conjunction with other characterization analyses, provides important information that can be used in the myriad of potential radioactive waste management alternatives.

  15. Diffraction Gratings for High-Intensity Laser Applications

    SciTech Connect

    Britten, J

    2008-01-23

    The scattering of light into wavelength-dependent discrete directions (orders) by a device exhibiting a periodic modulation of a physical attribute on a spatial scale similar to the wavelength of light has been the subject of study for over 200 years. Such a device is called a diffraction grating. Practical applications of diffraction gratings, mainly for spectroscopy, have been around for over 100 years. The importance of diffraction gratings in spectroscopy for the measurement of myriad properties of matter can hardly be overestimated. Since the advent of coherent light sources (lasers) in the 1960's, applications of diffraction gratings in spectroscopy have further exploded. Lasers have opened a vast application space for gratings, and apace, gratings have enabled entirely new classes of laser systems. Excellent reviews of the history, fundamental properties, applications and manufacturing techniques of diffraction gratings up to the time of their publication can be found in the books by Hutley (1) and more recently Loewen and Popov (2). The limited scope of this chapter can hardly do justice to such a comprehensive subject, so the focus here will be narrowly limited to characteristics required for gratings suitable for high-power laser applications, and methods to fabricate them. A particular area of emphasis will be on maximally-efficient large-aperture gratings for short-pulse laser generation.

  16. White-Light Diffraction with a CD

    ERIC Educational Resources Information Center

    Ivanov, Dragia Trifonov; Nikolaev, Stefan

    2010-01-01

    Various wave optics experiments can be carried out using an ordinary compact disc. The CD is suitable for use as a diffraction grating. For instance, a standard CD (700 MB) has 625 lines/mm. In this article, the authors describe two white-light diffraction demonstrations for a large audience, realizable using a CD (as reflection or transmission…

  17. Laser-written nanoporous silicon diffraction gratings for biosensors.

    PubMed

    Xia, Jinan; Giovannozzi, Andrea M; Sadeghi, Sheila J; Gilardi, Gianfranco; Rossi, Andrea M

    2013-12-20

    Surface-relief diffraction gratings and planar diffraction gratings directly written on nanoporous silicon layers using 514 nm continuous-wave lasers at very low power (less than 20 mW) were demonstrated. Diffraction-based biosensing application to detect arachidonic acid was experimentally demonstrated at incident light wavelength of 632.8 nm. A comparison in sensing applications was made between the two types of gratings to show the distinct advantage of the planar grating with selective functionalization. Laser-written planar gratings enable directly immobilizing biomolecules in the laser oxidized area of nanoporous silicon, resulting in a new patterned functionalization technique for biosensing applications. The functionalization technique can not only simplify the functionalization procedure in biosensing but also it has potential to increase the sensitivity of sensors by accurately defining grating patterns using the laser direct writing technique. PMID:24513946

  18. Laser-written nanoporous silicon diffraction gratings for biosensors.

    PubMed

    Xia, Jinan; Giovannozzi, Andrea M; Sadeghi, Sheila J; Gilardi, Gianfranco; Rossi, Andrea M

    2013-12-20

    Surface-relief diffraction gratings and planar diffraction gratings directly written on nanoporous silicon layers using 514 nm continuous-wave lasers at very low power (less than 20 mW) were demonstrated. Diffraction-based biosensing application to detect arachidonic acid was experimentally demonstrated at incident light wavelength of 632.8 nm. A comparison in sensing applications was made between the two types of gratings to show the distinct advantage of the planar grating with selective functionalization. Laser-written planar gratings enable directly immobilizing biomolecules in the laser oxidized area of nanoporous silicon, resulting in a new patterned functionalization technique for biosensing applications. The functionalization technique can not only simplify the functionalization procedure in biosensing but also it has potential to increase the sensitivity of sensors by accurately defining grating patterns using the laser direct writing technique.

  19. Notes: Laser Light Gets Everyone's Attention.

    ERIC Educational Resources Information Center

    Schmidt, Ellen

    1989-01-01

    Discusses laser demonstration for invoking interest in science, especially physics. Describes some examples, such as diffraction, scattering, expansion by diverging lens, internal reflection in a light pipe, and illumination through optical cable. Provides some practical hints for the demonstration. (YP)

  20. Explosively pumped laser light

    DOEpatents

    Piltch, Martin S.; Michelotti, Roy A.

    1991-01-01

    A single shot laser pumped by detonation of an explosive in a shell casing. The shock wave from detonation of the explosive causes a rare gas to luminesce. The high intensity light from the gas enters a lasing medium, which thereafter outputs a pulse of laser light to disable optical sensors and personnel.

  1. Ultrasonic light diffraction in optically isotropic media with induced birefringence

    NASA Astrophysics Data System (ADS)

    Blomme, Erik; Sliwinski, Antoni

    2001-11-01

    Optically isotropic media which are susceptible to acoustically induced birefringence can be used as acousto- optic polarization converters. A comparative study between fused silica and dense flint shows that at normal light incidence 52% of the light can be converted from linear to circular in the case of fused silica and only 20% in the case of dense flint. In each case the conversion appears at moderate sound amplitudes and at frequencies which are typical for the intermediate regime of diffraction. Applying oblique light incidence, most interesting effects can be obtained with fused silica at high sound frequencies which are typical for the Bragg regime of diffraction and in the neighborhood of the Bragg angle. The possibility is shown to use an AO cell fabricated of fused silica as a laser-beam splitter, converting a linearly polarized beam of light partially into a circularly polarized beam and a linearly polarized beam, the light intensity of the two beams being equal. In addition, it is seen that the temporal light intensity modulations which can be observed in the near field of the light diffracted under these specific conditions, can be understood from the polarization changes taking place.

  2. [Characteristics of laser light].

    PubMed

    Takac, S; Stojanović, S

    1999-01-01

    Laser is one of the greatest technical discoveries of the 20th century. It is important in basic sciences, but particularly in diagnosis and therapy of various pathologic conditions of human organism. It is electromagnetic radiation, not X-irradiation and, as such, it is not expected to produce new generation of iatrogenic malignancies. Laser falls between infrared and ultraviolet on the spectrum mainly in the visible light spectrum. Properties of laser light are: monochromacity (the same color), coherence (all of the light waves are in phase both spatially and temporally), collimation (all rays are parallel to each other and do not diverge significantly even over long distances). Lasers were first conceived by Einstein in 1917 when he wrote his "Zur Quantum Theorie der Strahlung" (the quantum theory of radiation) which enumerated concepts of stimulated and spontaneous emission and absorption. Drs. Arthur Schawlow and Charles Townes, in 1956, extended lasers into the optical frequency range and Maiman, in 1960, operated the first laser using ruby as the active medium (ruby laser). Laser is an acronym for Light Amplification by Stimulated Emission of Radiation. To understand the acronym, it is necessary to understand the basic physics of the atom. However, if the atom that is in the excited state is struck by another photon of energy before it returns to the ground state, two photons of equal frequency and energy, travelling in the same direction and in perfect spatial and temporal harmony, are produced. This phenomenon is termed stimulated emission of radiation. An external power source hyperexcites the atoms in the laser medium so that the number of atoms possessing upper energy levels exceeds the number of atoms in a power energy level, a condition termed a population inversion. This "pumping system" which imparts additional energy to the atoms may be optical, mechanical, or chemical. These atoms in a hyperexcited state spontaneously emit photons of light. The

  3. Remote Laser Diffraction Particle Size Distribution Analyzer

    SciTech Connect

    Batcheller, Thomas Aquinas; Huestis, Gary Michael; Bolton, Steven Michael

    2001-03-01

    In support of a radioactive slurry sampling and physical characterization task, an “off-the-shelf” laser diffraction (classical light scattering) particle size analyzer was utilized for remote particle size distribution (PSD) analysis. Spent nuclear fuel was previously reprocessed at the Idaho Nuclear Technology and Engineering Center (INTEC—formerly recognized as the Idaho Chemical Processing Plant) which is on DOE’s INEEL site. The acidic, radioactive aqueous raffinate streams from these processes were transferred to 300,000 gallon stainless steel storage vessels located in the INTEC Tank Farm area. Due to the transfer piping configuration in these vessels, complete removal of the liquid can not be achieved. Consequently, a “heel” slurry remains at the bottom of an “emptied” vessel. Particle size distribution characterization of the settled solids in this remaining heel slurry, as well as suspended solids in the tank liquid, is the goal of this remote PSD analyzer task. A Horiba Instruments Inc. Model LA-300 PSD analyzer, which has a 0.1 to 600 micron measurement range, was modified for remote application in a “hot cell” (gamma radiation) environment. This technology provides rapid and simple PSD analysis, especially down in the fine and microscopic particle size regime. Particle size analysis of these radioactive slurries down in this smaller range was not previously achievable—making this technology far superior than the traditional methods used. Successful acquisition of this data, in conjunction with other characterization analyses, provides important information that can be used in the myriad of potential radioactive waste management alternatives.

  4. Forward light scattering for arbitrary sharp-edged convex crystals in Fraunhofer and anomalous diffraction approximations.

    PubMed

    Heffels, C; Heitzmann, D; Hirleman, E D; Scarlett, B

    1995-10-01

    Fraunhofer diffraction is a well-known physical model for describing forward light scattering from opaque particles much larger than the wavelength of the light. Analytical expressions exist for diffraction from circular- or rectangular-shaped apertures. An expression is derived for diffraction by apertures of a general polygonal shape. From this expression the exact solution for anomalous diffraction by arbitrary convex crystals is calculated. These expressions are useful in characterizing crystal size and shape, by laser diffraction instruments, when measured in a solution.

  5. Integrated high-order surface diffraction gratings for diode lasers

    NASA Astrophysics Data System (ADS)

    Zolotarev, V. V.; Leshko, A. Yu; Pikhtin, N. A.; Slipchenko, S. O.; Sokolova, Z. N.; Lubyanskiy, Ya V.; Voronkova, N. V.; Tarasov, I. S.

    2015-12-01

    High-order surface diffraction gratings acting as a distributed Bragg reflector (DBR) in mesa stripe semiconductor lasers (λ = 1030 nm) have been studied theoretically and experimentally. Higher order interfering radiation modes (IRMs), which propagate off the plane of the waveguide, have been shown to have a crucial effect on the reflection and transmission spectra of the DBR. The decrease in the reflectivity of the DBR in response to the increase in the diffraction efficiency of these modes may reach 80% and more. According to theoretical analysis results, the intensity of the higher order IRMs is determined by the geometry of the DBR groove profile. Experimental data demonstrate that the noncavity modes are responsible for parasitic light leakage losses in the laser cavity. It has been shown that, in the case of nonoptimal geometry of the grating groove profile, the overall external differential quantum efficiency of the parasitic laser emission may exceed 45%, which is more than half of the laser output power. The optimal geometry of the DBR groove profile is trapezoidal, with the smallest possible lower base. Experimental evidence has been presented that this geometry considerably reduces the power of the higher order IRMs and minimises the parasitic light leakage loss.

  6. Verification of the Uncertainty Principle by Using Diffraction of Light Waves

    ERIC Educational Resources Information Center

    Nikolic, D.; Nesic, Lj

    2011-01-01

    We described a simple idea for experimental verification of the uncertainty principle for light waves. We used a single-slit diffraction of a laser beam for measuring the angular width of zero-order diffraction maximum and obtained the corresponding wave number uncertainty. We will assume that the uncertainty in position is the slit width. For the…

  7. Reconstruction of two-dimensional molecular structure with laser-induced electron diffraction from laser-aligned polyatomic molecules

    SciTech Connect

    Yu, Chao; Wei, Hui; Wang, Xu; Le, Anh -Thu; Lu, Ruifeng; Lin, C. D.

    2015-10-27

    Imaging the transient process of molecules has been a basic way to investigate photochemical reactions and dynamics. Based on laser-induced electron diffraction and partial one-dimensional molecular alignment, here we provide two effective methods for reconstructing two-dimensional structure of polyatomic molecules. We demonstrate that electron diffraction images in both scattering angles and broadband energy can be utilized to retrieve complementary structure information, including positions of light atoms. Lastly, with picometre spatial resolution and the inherent femtosecond temporal resolution of lasers, laser-induced electron diffraction method offers significant opportunities for probing atomic motion in a large molecule in a typical pump-probe measurement.

  8. Micron-Accurate Laser Fresnel-Diffraction Ranging System

    NASA Technical Reports Server (NTRS)

    Lehner, David; Campbell, Jonathan; Smith, Kelly; Sanders, Alvin; Allison, Stephen; Smaley, Larry

    2008-01-01

    Two versions of an optoelectronic system undergoing development are depicted. The system is expected to be capable of measuring a distance between 2 and 10 m with an error of no more than 1 micrometer. The system would be designed to exploit Fresnel diffraction of a laser beam. In particular, it would be designed to take advantage of the fact that a Fresnel diffraction pattern is ultrasensitive to distance. The two versions would differ in the following respects: In version 1, the focus of the telescope would be in the Fresnel region, and the telescope would have a small depth of focus. As a consequence, the Fresnel pattern would be imaged directly onto the photodetector array; in version 2, a multielement lens module would displace the Fresnel region from the vicinity of the pinhole to the vicinity of the optical receiver. As the distance to be measured varied, the location of the receiver relative to the displaced Fresnel-diffraction region would vary, thereby causing the Fresnel diffraction pattern on the focal plane to vary. The multielement lens module would also correct for aberrations. The processing of the digitized Fresnel diffraction pattern in the computer might be accelerated by using only parts of the pattern or even only one small part - the central pixel. As the distance from the pinhole increased, the central pixel would rapidly cycle between maximum and minimum light intensity. This in itself would not be sufficient to uniquely determine the distance. However, by varying the size of the pinhole or the wavelength of the laser, one could obtain a second cycle of variation of intensity that, in conjunction with the first cycle, could enable a unique determination of distance. Alternatively, for a single wavelength and a single pinhole size, it should suffice to consider the data from only two different key pixels in the Fresnel pattern.

  9. Ultrafast x-ray diffraction of laser-irradiated crystals

    NASA Astrophysics Data System (ADS)

    Heimann, P. A.; Larsson, J.; Chang, Z.; Lindenberg, A.; Schuck, P. J.; Judd, E.; Padmore, H. A.; Bucksbaum, P. H.; Lee, R. W.; Murnane, M.; Kapteyn, H.; Wark, J. S.; Falcone, R. W.

    1997-07-01

    An apparatus has been developed for measuring time-dependent x-ray diffraction. X-ray pulses from an Advanced Light Source bend magnet are diffracted by a sagittally-focusing Si (111) crystal and then by a sample crystal, presently InSb (111). Laser pulses with 100 fs duration and a repetition rate of 1 KHz irradiate the sample inducing a phase transition. Two types of detectors are being employed: an x-ray streak camera and an avalanche photodiode. The streak camera is driven by a photoconductive switch and has a 2 ps temporal resolution determined by trigger jitter. The avalanche photodiode has high quantum efficiency and sufficient time resolution to detect single x-ray pulses in ALS two bunch or `camshaft' operation. A beamline is under construction dedicated for time resolved and micro-diffraction experiments. In the new beamline a toroidal mirror collects 3 mrad horizontally and makes a 1:1 image of the bend magnet source in the x-ray hutch. A laser induced phase transition has been observed in InSb occurring within 70 ps.

  10. Laser light scattering review

    NASA Astrophysics Data System (ADS)

    Schaetzel, Klaus

    1989-08-01

    Since the development of laser light sources and fast digital electronics for signal processing, the classical discipline of light scattering on liquid systems experienced a strong revival plus an enormous expansion, mainly due to new dynamic light scattering techniques. While a large number of liquid systems can be investigated, ranging from pure liquids to multicomponent microemulsions, this review is largely restricted to applications on Brownian particles, typically in the submicron range. Static light scattering, the careful recording of the angular dependence of scattered light, is a valuable tool for the analysis of particle size and shape, or of their spatial ordering due to mutual interactions. Dynamic techniques, most notably photon correlation spectroscopy, give direct access to particle motion. This may be Brownian motion, which allows the determination of particle size, or some collective motion, e.g., electrophoresis, which yields particle mobility data. Suitable optical systems as well as the necessary data processing schemes are presented in some detail. Special attention is devoted to topics of current interest, like correlation over very large lag time ranges or multiple scattering.

  11. Laser light scattering review

    NASA Technical Reports Server (NTRS)

    Schaetzel, Klaus

    1989-01-01

    Since the development of laser light sources and fast digital electronics for signal processing, the classical discipline of light scattering on liquid systems experienced a strong revival plus an enormous expansion, mainly due to new dynamic light scattering techniques. While a large number of liquid systems can be investigated, ranging from pure liquids to multicomponent microemulsions, this review is largely restricted to applications on Brownian particles, typically in the submicron range. Static light scattering, the careful recording of the angular dependence of scattered light, is a valuable tool for the analysis of particle size and shape, or of their spatial ordering due to mutual interactions. Dynamic techniques, most notably photon correlation spectroscopy, give direct access to particle motion. This may be Brownian motion, which allows the determination of particle size, or some collective motion, e.g., electrophoresis, which yields particle mobility data. Suitable optical systems as well as the necessary data processing schemes are presented in some detail. Special attention is devoted to topics of current interest, like correlation over very large lag time ranges or multiple scattering.

  12. Investigation of diffractive optical element femtosecond laser machining

    NASA Astrophysics Data System (ADS)

    Chabrol, Grégoire R.; Ciceron, Adline; Twardowski, Patrice; Pfeiffer, Pierre; Flury, Manuel; Mermet, Frédéric; Lecler, Sylvain

    2016-06-01

    This paper presents an explorative study on the machining of diffractive optical elements (DOEs) in transparent materials using a femtosecond laser source. A simple form of DOE, a binary phase grating with a period of 20.85 μm (σ = 0.5 μm), a groove depth and width of 0.7 μm (σ = 0.2 μm) and 8.8 μm (σ = 0.5 μm) respectively, was successfully machined in BK7. The topographic characteristics were measured by white light interferometry and scanning electron microscopy (SEM). The processing was carried out on high precision stages with an ultrafast fibre laser (350 fs) emitting a 343 nm pulse focused onto the sample with a stationary microscope objective. A diffracted efficiency of 27%, obtained with a spectro goniometer, was corroborated by the theoretical results obtained by the Fourier modal method (FMM), taking into account the measured topographic values. These encouraging results demonstrate that high-speed femtosecond laser manufacturing of DOE in bulk glasses can be achieved, opening the way to rapid prototyping of multi-layered-DOEs.

  13. Fresnel Diffraction Using a He-Ne Gas Laser

    ERIC Educational Resources Information Center

    Moen, Allen L.; Vander Meulen, David L.

    1970-01-01

    Describes an advanced laboratory experiment of Fresnel diffraction which uses a He-Ne gas laser as the source and a wire as the opaque diffracting strip. A photograph of the diffraction pattern is compared with the intensity diagram predicted by the Cornu spiral method. Agreement is clear and impressive, although minor differences are detectable.…

  14. Hair treatment process providing dispersed colors by light diffraction

    SciTech Connect

    Lamartine, Bruce Carvell; Orler, E. Bruce; Sutton, Richard Matthew Charles; Song, Shuangqi

    2013-12-17

    Hair was coated with polymer-containing fluid and then hot pressed to form a composite of hair and a polymer film imprinted with a nanopattern. Polychromatic light incident on the nanopattern is diffracted into dispersed colored light.

  15. Hair treatment process providing dispersed colors by light diffraction

    SciTech Connect

    Lamartine, Bruce Carvell; Orler, E. Bruce; Sutton, Richard Matthew Charles; Song, Shuangqi

    2014-11-11

    Hair was coated with polymer-containing fluid and then hot pressed to form a composite of hair and a polymer film imprinted with a nanopattern. Polychromatic light incident on the nanopattern is diffracted into dispersed colored light.

  16. Hair treatment device for providing dispersed colors by light diffraction

    DOEpatents

    Lamartine, Bruce Carvell; Orler, Bruce E.; Sutton, Richard Matthew Charles; Song, Shuangqi

    2016-01-26

    Hair was coated with polymer-containing fluid and then hot pressed to form a composite of hair and a polymer film imprinted with a nanopattern. Polychromatic light incident on the nanopattern is diffracted into dispersed colored light.

  17. X-Ray Diffraction Simulation Using Laser Pointers and Printers.

    ERIC Educational Resources Information Center

    Johnson, Neil E.

    2001-01-01

    Uses a laser pointer to demonstrate the analogy between optical and X-ray diffraction and a laser printer with 600 or 1200 dot resolution to create and modify arrays, print them on transparencies, and illuminate them with laser pointers. Includes 14 references. (Author/YDS)

  18. Explication of diffraction lights on an optical imaging system from a Fraunhofer diffraction perspective

    NASA Astrophysics Data System (ADS)

    Ando, Takamasa; Korenaga, Tsuguhiro; Suzuki, Masa-aki

    2012-06-01

    Low-height camera modules are demanded for such applications as cellular phones and vehicles. For designing optical lens, it has widely been recognized that a trade-off exists between reducing the number of lenses and camera resolution. The optical performance of imaging lenses has been improved by diffraction gratings, which have a peculiar inverse dispersion in the wavelength and exhibit the efficacy of correction for chromatic aberration. We can simultaneously reduce the number of lenses and maintain optical resolution using diffraction gratings. However, we have found a generation of striped flare lights under intense light sources that differ from unnecessary order diffraction lights. In this paper, we reveal the generation mechanism of these new striped diffraction lights and suggest a novel structure of diffraction gratings that can decrease them.

  19. Lasers for ultrashort light pulses

    SciTech Connect

    Herrmann, J.; Wilhelmi, B.

    1987-01-01

    The present rapid expansion of research work on picosecond lasers and their application makes it difficult to survey and comprehend the large number of publications in this field. This book aims to provide an introduction to the field starting with the very basic and moving on to an advanced level. Contents: Fundamentals of the interaction between light pulses and matter; Fundamentals of lasers for ultrashort light pulses; Methods of measurement; Active modelocking; Synchronously pumped lasers; Passive modelocking of dye lasers; Passive modelocking of solid state lasers; Nonstationary nonlinear optical processes; Ultrafast spectroscopy.

  20. Erythrocyte shape analysis by means of laser diffraction

    NASA Astrophysics Data System (ADS)

    Bayer, Rainer; Schauf, Burkhard; Guenther, Bernd

    1992-05-01

    In quite a large number of disorders, reduced flexibility of red blood cells (RBC) can be detected. In cardiovascular diseases it is supposed that rigidification of RBC may be regarded as a pathogenetic factor aggravating ischemia by disturbing capillary perfusion. Most methods established so far to estimate RBC deformability are hard to standardize and include large measurement errors. We present a low-cost system to determine RBC shape and flexibility. It combines laser diffraction of RBC in Couette flow with automated computer assisted image analysis. Effortless handling allows the system to be used for RBC elongation measurements even in routine diagnostics. Analysis of the whole information content of diffraction patterns reduces errors due to noisy diffraction patterns of working a little off axis. The system allows detection of very small changes in flexibility (less than 5%). The accuracy of measurement is not affected by variation of hematocrit or the intensity of transmitted light. Using the newly developed system it is demonstrated (1) that mechanically induced RBC rigidification may occur without hemolysis; (2) that in photodynamic therapy (e.g., pheophorbide A) RBC rigidification occurs during irridation; and (3) that in-vitro aging of conserved blood may partly be inhibited by calmodulin antagonists (e.g., fendiline).

  1. Diffraction imaging characteristics of slit for ultra-short laser pulse

    NASA Astrophysics Data System (ADS)

    Yu, Xiang-yang; Wu, Kun-xi; Lu, Long-zhao

    2015-08-01

    We propose a simple and concise mathematical method based on the Fraunhofer approximation to analyze the imaging characteristics of slit for broadband light sources. Taking Gaussian-shaped ultra-short laser pulse for example, we investigated the diffraction imaging characteristics of ultra-short light sources through a single-slit and a double-slit. We deduced the mathematical expressions of the intensity distribution of far-field diffraction, and conducted numerical calculation and analysis. It turns out the pulse width of the ultra-short light source plays an important role in the diffraction imaging characteristics of slit. We also provide a quantitative criterion to measure the deviation in terms of far-field diffraction intensity distribution between broadband light source and the ideal monochromatic light source.

  2. Diffraction of entangled particles by light gratings

    SciTech Connect

    Sancho, Pedro

    2015-04-15

    We analyze the diffraction regime of the Kapitza–Dirac effect for particles entangled in momentum. The detection patterns show two-particle interferences. In the single-mode case we identify a discontinuity in the set of joint detection probabilities, associated with the disconnected character of the space of non-separable states. For Gaussian multi-mode states we derive the diffraction patterns, providing an example of the dependence of the light–matter interaction on entanglement. When the particles are identical, we can explore the relation between exchange and entanglement effects. We find a complementary behavior between overlapping and Schmidt’s number. In particular, symmetric entanglement can cancel the exchange effects. - Highlights: • Kapitza–Dirac diffraction of entangled particles shows multiparticle interference. • There is a discontinuity in the set of joint detection patterns of entangled states. • We find a complementary behavior between overlapping and Schmidt’s number. • Symmetric entanglement can cancel the exchange effects.

  3. Laser scattering induced holograms in lithium niobate. [observation of diffraction cones

    NASA Technical Reports Server (NTRS)

    Magnusson, R.; Gaylord, T. K.

    1974-01-01

    A 3.0-mm thick poled single crystal of lithium niobate doped with 0.1 mole% iron was exposed to a single beam and then to two intersecting beams of an argon ion laser operating at 515-nm wavelength. Laser scattering induced holograms were thus written and analyzed. The presence of diffraction cones was observed and is shown to result from the internally recorded interference pattern resulting from the interference of the original incident laser beam with light scattered from material inhomogeneities. This phenomenon is analyzed using Ewald sphere construction techniques which reveal the geometrical relationships existing for the diffraction cones.

  4. Atoms, Light, and Lasers

    NASA Astrophysics Data System (ADS)

    Bellac, Michel Le

    2014-11-01

    Up to now, the spatial properties of quantum particles played no more than a secondary role: we only needed the de Broglie relation (1.4) which gives the quantum particles wavelength, and our discussion of the quantum properties of photons was based mainly on their polarization, which is an internal degree of freedom of the photon. The probability amplitudes which we used did not involve the positions or velocities of the particles, which are spatial, or external degrees of freedom. In the present chapter, we shall introduce spatial dependence by defining probability amplitudes a(ěc r) that are functions of the position ěc r. In full generality, a(ěc r) is a complex number, but we shall avoid this complication and discuss only cases where the probability amplitudes may be taken real. For simplicity, we also limit ourselves to particles propagating along a straight line, which we take as the Ox axis: x will define the position of the particle and the corresponding probability amplitude will be a function of x, a(x). In our discussion, we shall need to introduce the so-called potential well, where a particle travels back and forth between two points on the straight line. One important particular case is the infinite well, where the particle is confined between two infinitely high walls over which it cannot pass. This example is not at all academic, and we shall meet it again in Chapter 6 when explaining the design of a laser diode! Furthermore, it will allow us to introduce the notion of energy level, to write down the Heisenberg inequalities, to understand the interaction of a light wave with an atom and finally to explain schematically the principles of the laser.

  5. Inquiry with Laser Printer Diffraction Gratings

    ERIC Educational Resources Information Center

    Van Hook, Stephen J.

    2007-01-01

    The pages of "The Physics Teacher" have featured several clever designs for homemade diffraction gratings using a variety of materials--cloth, lithographic film, wire, compact discs, parts of aerosol spray cans, and pseudoliquids and pseudosolids. A different and inexpensive method I use to make low-resolution diffraction gratings takes advantage…

  6. Laser diffraction for standardization of heterogeneous pharmaceutical preparations.

    PubMed

    Syroeshkin, A V; Popov, P I; Grebennikova, T V; Frolov, V A; Pleteneva, T V

    2005-04-29

    A new quantitative method for standardization of heterogeneous pharmaceutical preparations and their quality control during storage based on laser diffraction is proposed. A series of pharmaceutical dosage forms--suspensions, emulsions, tinctures, decoctions, cell preparations and others, are heterogeneous medicines. In some cases disperse phase can be formed during storage as a result of layering (L1/L2) or precipitation (S/L). Laser diffraction method proposed in this study can be used for standardization and quality control of medicines.

  7. Ultrasonic diffraction of Bessel light beams in uniaxial gyrotropic crystals

    NASA Astrophysics Data System (ADS)

    Belyi, V. N.; Kulak, G. V.; Krokh, G. V.; Ropot, P. I.; Shakin, O. V.

    2016-09-01

    Specific features of the acousto-optic diffraction of Bessel light beams propagating in the vicinity of the optical axis of a uniaxial gyrotropic crystal have been investigated. The dependences of the diffraction efficiency on the acousto-optic interaction length, ultrasound power, and polarization state of the incident Bessel light beam have been analyzed using the coupled-wave equations and the overlap-integral method. It is shown that polarization-independent diffraction of Bessel light beams is observed in paratellurite crystals, when the Bragg diffraction efficiency is independent of the polarization state of the incident beam. The physical reason for this diffraction has been established (both theoretically and experimentally) to be simultaneous implementation of two processes of anisotropic scattering, at which the Bragg synchronism conditions are satisfied for orthogonal polarized Bessel beams with elliptical polarization.

  8. Fraunhofer Diffraction Patterns from Apertures Illuminated with Nonparallel Light.

    ERIC Educational Resources Information Center

    Klingsporn, Paul E.

    1979-01-01

    Discusses several aspects of Fraunhofer diffraction patterns from apertures illuminated by diverging light. Develops a generalization to apertures of arbitrary shape which shows that the sizes of the pattern are related by a simple scale factor. Uses the Abbe theory of image formation by diffraction to discuss the intensity of illumination of the…

  9. Measurements of fine particle size using image processing of a laser diffraction image

    NASA Astrophysics Data System (ADS)

    Tsubaki, Kotaro

    2016-08-01

    The measurement of fine particle size is important in spray systems, minimum quantity lubrication, and weather observation. Introducing the recent progress of imaging techniques, the authors developed a portable measurement system. To overcome the large light intensity difference between the incident laser light and diffracted light and the limitation of the dynamic range of imaging devices, the event correlation was adopted. The growth of droplets in fog was experimentally measured.

  10. Wavelength control of visible light laser diodes

    NASA Astrophysics Data System (ADS)

    Goto, N.; Fujii, T.; Nemoto, K.; Suzuki, H.; Nakagawa, K.; Otsu, M.

    1990-04-01

    Wavelength control of visible light laser diodes was studied. By combining an interferometer and a diffraction grating, it became possible to control the wavelength of continuous oscillation in the range of 664 to 673nm, the frequency fine control range being 2GHz. And the spectral linewidth was narrowed to about 44kHz (10 exp minus 7 nm). With the use of a collimator lens, the beam expansion was narrowed to 2mrad. It was confirmed that the pulse output of continuous oscillation visible light laser diodes can be amplified by the YAG laser excitation dye laser. In the case of pulse oscillation, oscillation of 1GHz spectral width was obtained at the wavelength of 0.8 micro m by using an injection synchronization method. In the injection synchronization method, other laser beam is injected in an oscillator and a superior laser beam of synchronized components alone is obtained. As the wavelength control method is now stabilized and satisfies the conditions of narrow band, it has the prospect to be applied to the laser uranium enrichment technology.

  11. Light diffraction by acoustically induced domains in nematic liquid crystals

    SciTech Connect

    Kapustina, O. A.

    2006-05-15

    The phenomenon of light diffraction by a system of linear domains formed in planar layers of nematic liquid crystals in an oscillating Couette flow, acoustically induced at sound frequencies, is investigated.

  12. Diffraction patterns from multiple tilted laser apertures: numerical analysis

    NASA Astrophysics Data System (ADS)

    Kovalev, Anton V.; Polyakov, Vadim M.

    2016-03-01

    We propose a Rayleigh-Sommerfeld based method for numerical calculation of multiple tilted apertures near and far field diffraction patterns. Method is based on iterative procedure of fast Fourier transform based circular convolution of the initial field complex amplitudes distribution and impulse response function modified in order to account aperture and observation planes mutual tilt. The method is computationally efficient and has good accordance with the results of experimental diffraction patterns and can be applied for analysis of spatial noises occurring in master oscillator power amplifier laser systems. The example of diffraction simulation for a Phobos-Ground laser rangefinder amplifier is demonstrated.

  13. Diffraction effect of the injected beam in axisymmetrical structural CO2 laser

    NASA Astrophysics Data System (ADS)

    Xu, Yonggen; Wang, Shijian; Fan, Qunchao

    2012-07-01

    Diffraction effect of the injected beam in axisymmetrical structural CO2 laser is studied based on the injection-locking principle. The light intensity of the injected beam at the plane where the holophotes lie is derived according to the Huygens-Fresnel diffraction integral equation. And then the main parameters which influence the diffraction light intensity are given. The calculated results indicate that the first-order diffraction signal will play an important role in the phase-locking when the zero-order diffraction cannot reach the folded cavities. The numerical examples are given to confirm the correctness of the results, and the comparisons between the theoretical and the experimental results are illustrated.

  14. Toward atomic resolution diffractive imaging of isolated molecules with X-ray free-electron lasers.

    PubMed

    Stern, S; Holmegaard, L; Filsinger, F; Rouzée, A; Rudenko, A; Johnsson, P; Martin, A V; Barty, A; Bostedt, C; Bozek, J; Coffee, R; Epp, S; Erk, B; Foucar, L; Hartmann, R; Kimmel, N; Kühnel, K-U; Maurer, J; Messerschmidt, M; Rudek, B; Starodub, D; Thøgersen, J; Weidenspointner, G; White, T A; Stapelfeldt, H; Rolles, D; Chapman, H N; Küpper, J

    2014-01-01

    We give a detailed account of the theoretical analysis and the experimental results of an X-ray-diffraction experiment on quantum-state selected and strongly laser-aligned gas-phase ensembles of the prototypical large asymmetric rotor molecule 2,5-diiodobenzonitrile, performed at the Linac Coherent Light Source [Phys. Rev. Lett.112, 083002 (2014)]. This experiment is the first step toward coherent diffractive imaging of structures and structural dynamics of isolated molecules at atomic resolution, i.e., picometers and femtoseconds, using X-ray free-electron lasers.

  15. Toward atomic resolution diffractive imaging of isolated molecules with X-ray free-electron lasers.

    PubMed

    Stern, S; Holmegaard, L; Filsinger, F; Rouzée, A; Rudenko, A; Johnsson, P; Martin, A V; Barty, A; Bostedt, C; Bozek, J; Coffee, R; Epp, S; Erk, B; Foucar, L; Hartmann, R; Kimmel, N; Kühnel, K-U; Maurer, J; Messerschmidt, M; Rudek, B; Starodub, D; Thøgersen, J; Weidenspointner, G; White, T A; Stapelfeldt, H; Rolles, D; Chapman, H N; Küpper, J

    2014-01-01

    We give a detailed account of the theoretical analysis and the experimental results of an X-ray-diffraction experiment on quantum-state selected and strongly laser-aligned gas-phase ensembles of the prototypical large asymmetric rotor molecule 2,5-diiodobenzonitrile, performed at the Linac Coherent Light Source [Phys. Rev. Lett.112, 083002 (2014)]. This experiment is the first step toward coherent diffractive imaging of structures and structural dynamics of isolated molecules at atomic resolution, i.e., picometers and femtoseconds, using X-ray free-electron lasers. PMID:25415561

  16. National Ignition Facility main laser stray light analysis and control

    SciTech Connect

    English, R E; Miller, J L; Peterson, G; Schweyen, J

    1998-06-26

    Stray light analysis has been carried out for the main laser section of the National Ignition Facility main laser section using a comprehensive non-sequential ray trace model supplemented with additional ray trace and diffraction propagation modeling. This paper describes the analysis and control methodology, gives examples of ghost paths and required tilted lenses, baffles, absorbers, and beam dumps, and discusses analysis of stray light "pencil beams" in the system.

  17. Note: Design of a laser feedback interferometer with double diffraction system

    SciTech Connect

    Guo, Dongmei Wang, Ming

    2015-09-15

    A novel laser feedback interferometer with double diffraction system is proposed in this paper. A beam emitted from the laser is incident onto a transmission grating. The mth order beam is vertically reflected by a mirror and diffracted again by the grating. The double-diffracted beam returns into the laser cavity and mixes with the light inside the active cavity, thus generating a modulation of both the amplitude and the frequency of the lasing field. Theoretical analysis and experimental observations show that the output signal of the proposed system depends on the grating pitch and the direction of the phase movement can be obtained from inclination of the interference signal. It provides a potential displacement sensor with high stability and quite a compact configuration.

  18. Time-dependent dynamic behavior of light diffraction in ferrofluid

    NASA Astrophysics Data System (ADS)

    Chung, Min-Feng; Chou, S. E.; Fu, Chao-Ming

    2012-04-01

    The time-dependent dynamic behavior of diffraction patterns induced by external magnetic field in a suspension of nano-sized magnetic particles (Fe3O4) in a water-based magnetic fluid was investigated. It was observed that the diffraction pattern changed with time as the magnetic field was applied. In the absence of applied magnetic field, there was no diffraction pattern in the screen. When the magnetic field was applied, the transmitted light was perpendicular to the magnetic field, and the diffraction pattern was unstable. There were many small lines and points moving with time. After one minute, the diffraction pattern turned stable, and the small lines became longer. This time-dependent behavior helps us to understand the evolution of the forming chains of magnetic nanoparticles. Moreover, we have measured the other diffraction pattern, the transmitted light propagating parallel to the applied field. These time-dependent diffraction patterns give a new point to understand the dynamic three-dimensional structure of magnetic fluid under a dc magnetic field.

  19. Diffraction effects in length measurements by laser interferometry.

    PubMed

    Sasso, C P; Massa, E; Mana, G

    2016-03-21

    High-accuracy dimensional measurements by laser interferometers require corrections because of diffraction, which makes the effective fringe-period different from the wavelength of a plane (or spherical) wave λ0. By using a combined X-ray and optical interferometer as a tool to investigate diffraction across a laser beam, we observed wavelength variations as large as 10-8λ0. We show that they originate from the wavefront evolution under paraxial propagation in the presence of wavefront- and intensity-profile perturbations.

  20. Diffraction effects in length measurements by laser interferometry.

    PubMed

    Sasso, C P; Massa, E; Mana, G

    2016-03-21

    High-accuracy dimensional measurements by laser interferometers require corrections because of diffraction, which makes the effective fringe-period different from the wavelength of a plane (or spherical) wave λ0. By using a combined X-ray and optical interferometer as a tool to investigate diffraction across a laser beam, we observed wavelength variations as large as 10-8λ0. We show that they originate from the wavefront evolution under paraxial propagation in the presence of wavefront- and intensity-profile perturbations. PMID:27136842

  1. Laser Light Scattering by Shock Waves

    NASA Technical Reports Server (NTRS)

    Panda, J.; Adamovsky, G.

    1995-01-01

    Scattering of coherent light as it propagates parallel to a shock wave, formed in front of a bluff cylindrical body placed in a supersonic stream, is studied experimentally and numerically. Two incident optical fields are considered. First, a large diameter collimated beam is allowed to pass through the shock containing flow. The light intensity distribution in the resultant shadowgraph image, measured by a low light CCD camera, shows well-defined fringes upstream and downstream of the shadow cast by the shock. In the second situation, a narrow laser beam is brought to a grazing incidence on the shock and the scattered light, which appears as a diverging sheet from the point of interaction, is visualized and measured on a screen placed normal to the laser path. Experiments are conducted on shocks formed at various free-stream Mach numbers, M, and total pressures, P(sub 0). It is found that the widths of the shock shadows in a shadowgraph image become independent of M and P(sub 0) when plotted against the jump in the refractive index, (Delta)n, created across the shock. The total scattered light measured from the narrow laser beam and shock interaction also follows the same trend. In the numerical part of the study, the shock is assumed to be a 'phase object', which introduces phase difference between the upstream and downstream propagating parts of the light disturbances. For a given shape and (Delta)n of the bow shock the phase and amplitude modulations are first calculated by ray tracing. The wave front is then propagated to the screen using the Fresnet diffraction equation. The calculated intensity distribution, for both of the incident optical fields, shows good agreement with the experimental data.

  2. Light Diffraction by Large Amplitude Ultrasonic Waves in Liquids

    NASA Technical Reports Server (NTRS)

    Adler, Laszlo; Cantrell, John H.; Yost, William T.

    2016-01-01

    Light diffraction from ultrasound, which can be used to investigate nonlinear acoustic phenomena in liquids, is reported for wave amplitudes larger than that typically reported in the literature. Large amplitude waves result in waveform distortion due to the nonlinearity of the medium that generates harmonics and produces asymmetries in the light diffraction pattern. For standing waves with amplitudes above a threshold value, subharmonics are generated in addition to the harmonics and produce additional diffraction orders of the incident light. With increasing drive amplitude above the threshold a cascade of period-doubling subharmonics are generated, terminating in a region characterized by a random, incoherent (chaotic) diffraction pattern. To explain the experimental results a toy model is introduced, which is derived from traveling wave solutions of the nonlinear wave equation corresponding to the fundamental and second harmonic standing waves. The toy model reduces the nonlinear partial differential equation to a mathematically more tractable nonlinear ordinary differential equation. The model predicts the experimentally observed cascade of period-doubling subharmonics terminating in chaos that occurs with increasing drive amplitudes above the threshold value. The calculated threshold amplitude is consistent with the value estimated from the experimental data.

  3. 100-watt fiber-based green laser with near diffraction-limited beam quality

    NASA Astrophysics Data System (ADS)

    Hu, Dan; Eisenberg, Eric; Brar, Khush; Yilmaz, Tolga; Honea, Eric

    2010-02-01

    An air-cooled, light-weight, fiber-based, high power green laser has been prototyped. The system consists of an all-fibercoupled IR pump laser at 1064 nm and a frequency-conversion module in a compact and flexible configuration. The IR laser operates in QCW mode, with 10 MHz pulse repetition frequency and 3-5 ns pulse width, to generate sufficient peak power for frequency doubling in the converter module. The IR laser can produce more than 200 W in a linearlypolarized diffraction-limited output beam with high spectral brightness for frequency conversion. The converter module has an input telescope and an oven with a nonlinear crystal to efficiently convert the 1064-nm IR fiber laser output to 532-nm green output. The IR laser and conversion module are connected via a stainless-steel protected delivery fiber for optical beam delivery and an electrical cable harness for electrical power delivery and system control. The beam quality of the 532 nm output remains near diffraction-limited, with M2<1.4. Up to 101 W of 532 nm output was demonstrated and multi-hour runs were characterized at 75 W output. The weights of the IR laser package and doubler are 69 lbs and 14 lbs respectively. An overview of the system and full characterization results will be presented. Such compact, highbrightness green laser sources are expected to enable various scientific, defense and industrial applications.

  4. Design and fabrication of diffraction imaging elements for common Gaussian laser beam in terahertz frequency

    NASA Astrophysics Data System (ADS)

    Liu, Jianfeng; Gong, Jinhui; Liu, Kan; Zhang, Xinyu; Xie, Changsheng

    2011-11-01

    A special software is constructed effectively for reconstructing the fine phase distribution of the diffracted Gaussian laser beams in the terahertz frequency range, according to common diffraction theory. The fine surface microrelief patterns of the elements, which originate from the simple patterns in photomask and further etched onto the surface of {100}- oriented silicon wafer by a low cost and rapid method, are created by the software above according to the phase distribution designed. Being different with the traditional silicon diffractive lenses fabricated by multiple level processes, the elements produced by the method introduced by us can transfer common Gaussian beams into desired images through created fine patterns over the surface of the elements. Two typical type of diffractive elements, which are used to transform common Gaussian laser beams in terahertz frequency into highly focused spot or so-called common focus, and the desired figure of the "umber one", are designed and fabricated. For testing the element, the LASER SIEIR 50 of Coherent Company is used to generate common Gaussian laser beams (the diameter of the beams is 10mm), and the PYROCAM THERE of Spiricon Company is also used to display the images acquired. Experimental results show that the elements can be used to form needed light fields and expected images, respectively.

  5. White-light diffraction tomography of unlabelled live cells

    NASA Astrophysics Data System (ADS)

    Kim, Taewoo; Zhou, Renjie; Mir, Mustafa; Babacan, S. Derin; Carney, P. Scott; Goddard, Lynford L.; Popescu, Gabriel

    2014-03-01

    We present a technique called white-light diffraction tomography (WDT) for imaging microscopic transparent objects such as live unlabelled cells. The approach extends diffraction tomography to white-light illumination and imaging rather than scattering plane measurements. Our experiments were performed using a conventional phase contrast microscope upgraded with a module to measure quantitative phase images. The axial dimension of the object was reconstructed by scanning the focus through the object and acquiring a stack of phase-resolved images. We reconstructed the three-dimensional structures of live, unlabelled, red blood cells and compared the results with confocal and scanning electron microscopy images. The 350 nm transverse and 900 nm axial resolution achieved reveals subcellular structures at high resolution in Escherichia coli cells. The results establish WDT as a means for measuring three-dimensional subcellular structures in a non-invasive and label-free manner.

  6. Hair treatment process providing dispersed colors by light diffraction

    SciTech Connect

    Sutton, Richard Matthew Charles; Lamartine, Bruce Carvell; Orler, E. Bruce; Song, Shuangqi

    2015-12-22

    A hair treatment process for providing dispersed colors by light diffraction including (a) coating the hair with a material comprising a polymer, (b) pressing the hair with a pressing device including one or more surfaces, and (c) forming a secondary nanostructured surface pattern on the hair that is complementary to the primary nanostructured surface pattern on the one or more surfaces of the pressing device. The secondary nanostructured surface pattern diffracts light into dispersed colors that are visible on the hair. The section of the hair is pressed with the pressing device for from about 1 to 55 seconds. The polymer has a glass transition temperature from about 55.degree. C. to about 90.degree. C. The one or more surfaces include a primary nanostructured surface pattern.

  7. Two-Photon Microscopy with Diffractive Optical Elements and Spatial Light Modulators

    PubMed Central

    Watson, Brendon O.; Nikolenko, Volodymyr; Araya, Roberto; Peterka, Darcy S.; Woodruff, Alan; Yuste, Rafael

    2010-01-01

    Two-photon microscopy is often performed at slow frame rates due to the need to serially scan all points in a field of view with a single laser beam. To overcome this problem, we have developed two optical methods that split and multiplex a laser beam across the sample. In the first method a diffractive optical element (DOE) generates a fixed number of beamlets that are scanned in parallel resulting in a corresponding increase in speed or in signal-to-noise ratio in time-lapse measurements. The second method uses a computer-controlled spatial light modulator (SLM) to generate any arbitrary spatio-temporal light pattern. With an SLM one can image or photostimulate any predefined region of the image such as neurons or dendritic spines. In addition, SLMs can be used to mimic a large number of optical transfer functions including light path corrections as adaptive optics. PMID:20859526

  8. Computation of Diffractive Beam Propagation of Monochromatic Light

    1999-02-20

    Computation of diffractive beam propagation of monochromatic light through a l-dimensional (slab) structure defined by a piecewise continuous complex index of refraction. Finite difference equations are fourth-order-accurate in the lateral grid size and include discontinuities of higher-order field derivatives at dielectric interfaces. Variable grid spacing is allowed, and all dielectric interfaces are assumed to coincide with grid points.

  9. Theoretical Fraunhofer light diffraction patterns calculated from three-dimensional sarcomere arrays imaged from isolated cardiac cells at rest.

    PubMed

    Roos, K P; Leung, A F

    1987-08-01

    Sarcomere striation positions have been obtained throughout the volumes of calcium-tolerant resting heart cells by direct computer interfaced high-resolution optical imaging. Each sarcomere position is stored in a three-dimensional (3-D) matrix array from which Fraunhofer light diffraction patterns have been calculated using numerical methods based on Fourier transforms. Diffraction patterns have been calculated from heart cell data arrays oriented normal to a theoretical laser beam. Twelve characteristic features have been identified and described from these diffraction patterns that correlate to diffraction phenomena observed from both cardiac and skeletal muscle. This numerical approach provides the means to directly assess diffraction pattern formulation, the precision of layer line angular separation, layer-line intensity and angular asymmetries, line widths and fine structures in terms of the known diffracting source structures. These results confirm that theoretical calculations can predict real muscle diffraction patterns and their asymmetries.

  10. Measuring Spray Droplet Size from Agricultural Nozzles Using Laser Diffraction.

    PubMed

    Fritz, Bradley K; Hoffmann, W Clint

    2016-01-01

    When making an application of any crop protection material such as an herbicide or pesticide, the applicator uses a variety of skills and information to make an application so that the material reaches the target site (i.e., plant). Information critical in this process is the droplet size that a particular spray nozzle, spray pressure, and spray solution combination generates, as droplet size greatly influences product efficacy and how the spray moves through the environment. Researchers and product manufacturers commonly use laser diffraction equipment to measure the spray droplet size in laboratory wind tunnels. The work presented here describes methods used in making spray droplet size measurements with laser diffraction equipment for both ground and aerial application scenarios that can be used to ensure inter- and intra-laboratory precision while minimizing sampling bias associated with laser diffraction systems. Maintaining critical measurement distances and concurrent airflow throughout the testing process is key to this precision. Real time data quality analysis is also critical to preventing excess variation in the data or extraneous inclusion of erroneous data. Some limitations of this method include atypical spray nozzles, spray solutions or application conditions that result in spray streams that do not fully atomize within the measurement distances discussed. Successful adaption of this method can provide a highly efficient method for evaluation of the performance of agrochemical spray application nozzles under a variety of operational settings. Also discussed are potential experimental design considerations that can be included to enhance functionality of the data collected. PMID:27684589

  11. Measuring Spray Droplet Size from Agricultural Nozzles Using Laser Diffraction.

    PubMed

    Fritz, Bradley K; Hoffmann, W Clint

    2016-09-16

    When making an application of any crop protection material such as an herbicide or pesticide, the applicator uses a variety of skills and information to make an application so that the material reaches the target site (i.e., plant). Information critical in this process is the droplet size that a particular spray nozzle, spray pressure, and spray solution combination generates, as droplet size greatly influences product efficacy and how the spray moves through the environment. Researchers and product manufacturers commonly use laser diffraction equipment to measure the spray droplet size in laboratory wind tunnels. The work presented here describes methods used in making spray droplet size measurements with laser diffraction equipment for both ground and aerial application scenarios that can be used to ensure inter- and intra-laboratory precision while minimizing sampling bias associated with laser diffraction systems. Maintaining critical measurement distances and concurrent airflow throughout the testing process is key to this precision. Real time data quality analysis is also critical to preventing excess variation in the data or extraneous inclusion of erroneous data. Some limitations of this method include atypical spray nozzles, spray solutions or application conditions that result in spray streams that do not fully atomize within the measurement distances discussed. Successful adaption of this method can provide a highly efficient method for evaluation of the performance of agrochemical spray application nozzles under a variety of operational settings. Also discussed are potential experimental design considerations that can be included to enhance functionality of the data collected.

  12. Ultrafast large-area micropattern generation in nonabsorbing polymer thin films by pulsed laser diffraction.

    PubMed

    Verma, Ankur; Sharma, Ashutosh; Kulkarni, Giridhar U

    2011-03-21

    An ultrafast, parallel, and beyond-the-master micropatterning technique for ultrathin (30-400 nm) nonabsorbing polymer films by diffraction of laser light through a 2D periodic aperture is reported. The redistribution of laser energy absorbed by the substrate causes self-organization of polymer thin films in the form of wrinklelike surface relief structures caused by localized melting and freezing of the thin film. Unlike conventional laser ablation and laser writing processes, low laser fluence is employed to only passively swell the polymer as a pre-ablative process without loss of material, and without absorption/reaction with incident radiation. Self-organization in the thin polymer film, aided by the diffraction pattern, produces microstructures made up of thin raised lines. These regular microstructures have far more complex morphologies than the mask geometry and very narrow line widths that can be an order of magnitude smaller than the openings in the mask. The microstructure morphology is easily modulated by changing the film thickness, aperture size, and geometry, and by changing the diffraction pattern.

  13. 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.

  14. Powder X-ray Diffraction Using the Omega Laser

    NASA Astrophysics Data System (ADS)

    Eggert, Jon; Rygg, Ryan; Smith, Raymond; Bastea, Marina; Ping, Yuan; Shepherd, Ronnie; Collins, Gilbert

    2009-06-01

    The past several years have seen dramatic improvements in dynamic ramp-compression experiments to measure stress-density using laser and pulsed-power drivers. Goals for future experiments center on achieving pressures over 1 TPa (10 Mbar), while keeping the samples in a solid phase and applying additional diagnostics to probe the nature of these states. X-ray scattering is a natural probe for such studies due to the copious x-ray energy produced by laser sources. Such experiments allow studies of the crystal structure, texture, strength, and possibly temperature of ramp-compressed solids at unprecedented density. With this in mind we have developed a powder x-ray diffraction diagnostic fielded at the Omega laser. We will report our results on ramp-driven iron, tin and copper. This work performed under the auspices of the U.S. DOE by LLNL under Contract DE-AC52-07NA27344.

  15. Diffractive beam shaping for enhanced laser polymer welding

    NASA Astrophysics Data System (ADS)

    Rauschenberger, J.; Vogler, D.; Raab, C.; Gubler, U.

    2015-03-01

    Laser welding of polymers increasingly finds application in a large number of industries such as medical technology, automotive, consumer electronics, textiles or packaging. More and more, it replaces other welding technologies for polymers, e. g. hot-plate, vibration or ultrasonic welding. At the same rate, demands on the quality of the weld, the flexibility of the production system and on processing speed have increased. Traditionally, diode lasers were employed for plastic welding with flat-top beam profiles. With the advent of fiber lasers with excellent beam quality, the possibility to modify and optimize the beam profile by beam-shaping elements has opened. Diffractive optical elements (DOE) can play a crucial role in optimizing the laser intensity profile towards the optimal M-shape beam for enhanced weld seam quality. We present results on significantly improved weld seam width constancy and enlarged process windows compared to Gaussian or flat-top beam profiles. Configurations in which the laser beam diameter and shape can be adapted and optimized without changing or aligning the laser, fiber-optic cable or optical head are shown.

  16. 5-Femtosecond Laser-Electron Synchronization for Pump-Probe Crystallography and Diffraction

    NASA Astrophysics Data System (ADS)

    Walbran, Matthew; Gliserin, Alexander; Jung, Kwangyun; Kim, Jungwon; Baum, Peter

    2015-10-01

    For improving the temporal resolution in ultrafast pump-probe electron or x-ray diffraction, we report a laser-electron synchronization concept via direct microwave extraction from the laser frequency comb combined with phase detection by fiber-loop interferometry, in situ drift correction via electron-energy analysis, and laser-electron streaking for final timing metrology. We achieve a laser-electron jitter below 5 fs (rms) integrated between 8 min and Nyquist period (400 ns). Slower drifts are also below 5 fs (rms) after active compensation. This result helps advance femtosecond crystallography with electrons or x rays to the regime of fundamental atomic-scale dynamics and light-matter interaction.

  17. Discrete wavelength-locked external cavity laser

    NASA Technical Reports Server (NTRS)

    Pilgrim, Jeffrey S. (Inventor); Silver, Joel A. (Inventor)

    2005-01-01

    An external cavity laser (and method of generating laser light) comprising: a laser light source; means for collimating light output by the laser light source; a diffraction grating receiving collimated light; a cavity feedback mirror reflecting light received from the diffraction grating back to the diffraction grating; and means for reliably tuning the external cavity laser to discrete wavelengths.

  18. Enhanced light absorption of solar cells and photodetectors by diffraction

    DOEpatents

    Zaidi, Saleem H.; Gee, James M.

    2005-02-22

    Enhanced light absorption of solar cells and photodetectors by diffraction is described. Triangular, rectangular, and blazed subwavelength periodic structures are shown to improve performance of solar cells. Surface reflection can be tailored for either broadband, or narrow-band spectral absorption. Enhanced absorption is achieved by efficient optical coupling into obliquely propagating transmitted diffraction orders. Subwavelength one-dimensional structures are designed for polarization-dependent, wavelength-selective absorption in solar cells and photodetectors, while two-dimensional structures are designed for polarization-independent, wavelength-selective absorption therein. Suitable one and two-dimensional subwavelength periodic structures can also be designed for broadband spectral absorption in solar cells and photodetectors. If reactive ion etching (RIE) processes are used to form the grating, RIE-induced surface damage in subwavelength structures can be repaired by forming junctions using ion implantation methods. RIE-induced surface damage can also be removed by post RIE wet-chemical etching treatments.

  19. Laue diffraction protein crystallography at the National Synchrotron Light Source

    SciTech Connect

    Getzoff, E.D.; McRee, D. ); Jones, K.W.; Spanne, P.; Sweet, R.M. ); Moffat, K.; Ng, K.; Rivers, M.L.; Schildkamp, W.; Teng, T.Y. ); Singer, P.T.; Westbrook, E.M. )

    1992-01-01

    A new facility for the study of protein crystal structure using Laue diffraction has been established at the X26 beam line of the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory. The characteristics of the beam line and diffraction apparatus are described. Selected results of some of the initial experiments are discussed briefly by beam line users to illustrate the scope of the experimental program. Because the Laue method permits the recording of large data sets in a single shot, one goal in establishing this facility has been to develop the means to study time-resolved structures within protein crystals. Systems being studied include: the reactions catalyzed by trypsin; photolysis of carbonmonoxy myoglobin; and the photocycle of photoactive yellow protein.

  20. Laue diffraction protein crystallography at the National Synchrotron Light Source

    SciTech Connect

    Getzoff, E.D.; McRee, D.; Jones, K.W.; Spanne, P.; Sweet, R.M.; Moffat, K.; Ng, K.; Rivers, M.L.; Schildkamp, W.; Teng, T.Y.; Singer, P.T.; Westbrook, E.M.

    1992-12-31

    A new facility for the study of protein crystal structure using Laue diffraction has been established at the X26 beam line of the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory. The characteristics of the beam line and diffraction apparatus are described. Selected results of some of the initial experiments are discussed briefly by beam line users to illustrate the scope of the experimental program. Because the Laue method permits the recording of large data sets in a single shot, one goal in establishing this facility has been to develop the means to study time-resolved structures within protein crystals. Systems being studied include: the reactions catalyzed by trypsin; photolysis of carbonmonoxy myoglobin; and the photocycle of photoactive yellow protein.

  1. 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

  2. Diffractive simultaneous bidirectional shearing interferometry using tailored spatially coherent light

    SciTech Connect

    Nercissian, Vanusch; Harder, Irina; Mantel, Klaus; Berger, Andreas; Leuchs, Gerd; Lindlein, Norbert; Schwider, Johannes

    2011-02-01

    Measurements of wavefront deformations can be carried out with the help of lateral shearing interferometers. Here the focus is on a setup providing two shears along orthogonal directions simultaneously to generate the data needed for a reconstruction. We describe a diffractive solution using Ronchi phase gratings with a suppressed zeroth order for both the doubling of the wavefront under test and the bidirectional shearing unit. A series arrangement of the gratings offers an on-axis geometry, which minimizes the systematic errors of the test. For illumination, an extended incoherent monochromatic light source is used. High-contrast fringes can be obtained by tailoring the degree of coherence via a periodic intensity distribution.

  3. Performance comparison of Malvern instruments laser diffraction drop size analyzer

    NASA Technical Reports Server (NTRS)

    Hirleman, E. D.; Dodge, L. G.

    1986-01-01

    The performance of ten laser diffraction particle sizing instruments (Malvern models 2200 and 2600) has been evaluated using a synthetic particle size reference standard in a round-robin test at nine independent laboratories. A calibration reticle consisting of a two-dimensional array of opaque, circular particle images photoetched in chrome thin film deposited on a glass substrate was used as the reference. Mean diameters (e.g., D32) for the reticle measured by the ten unmodified instruments varied by 27 percent. In contrast, data from six instruments with individually calibrated photodetector correction factors demonstrated much better agreement and were within 2.6 percent of the actual reticle properties.

  4. Sub-diffraction Laser Synthesis of Silicon Nanowires

    PubMed Central

    Mitchell, James I.; Zhou, Nan; Nam, Woongsik; Traverso, Luis M.; Xu, Xianfan

    2014-01-01

    We demonstrate synthesis of silicon nanowires of tens of nanometers via laser induced chemical vapor deposition. These nanowires with diameters as small as 60 nm are produced by the interference between incident laser radiation and surface scattered radiation within a diffraction limited spot, which causes spatially confined, periodic heating needed for high resolution chemical vapor deposition. By controlling the intensity and polarization direction of the incident radiation, multiple parallel nanowires can be simultaneously synthesized. The nanowires are produced on a dielectric substrate with controlled diameter, length, orientation, and the possibility of in-situ doping, and therefore are ready for device fabrication. Our method offers rapid one-step fabrication of nano-materials and devices unobtainable with previous CVD methods. PMID:24469704

  5. Sub-diffraction Laser Synthesis of Silicon Nanowires

    NASA Astrophysics Data System (ADS)

    Mitchell, James I.; Zhou, Nan; Nam, Woongsik; Traverso, Luis M.; Xu, Xianfan

    2014-01-01

    We demonstrate synthesis of silicon nanowires of tens of nanometers via laser induced chemical vapor deposition. These nanowires with diameters as small as 60 nm are produced by the interference between incident laser radiation and surface scattered radiation within a diffraction limited spot, which causes spatially confined, periodic heating needed for high resolution chemical vapor deposition. By controlling the intensity and polarization direction of the incident radiation, multiple parallel nanowires can be simultaneously synthesized. The nanowires are produced on a dielectric substrate with controlled diameter, length, orientation, and the possibility of in-situ doping, and therefore are ready for device fabrication. Our method offers rapid one-step fabrication of nano-materials and devices unobtainable with previous CVD methods.

  6. Measurement of erythrocyte deformability by two laser diffraction methods.

    PubMed

    Wang, X; Zhao, H; Zhuang, F Y; Stoltz, J F

    1999-01-01

    The aim of this work is to study the deformability of red blood cells (RBC) by two laser diffraction methods: the Laser-assisted Optical Rotational Cell Analyser (LORCA, Mechatronics, Amsterdam, Netherlands) and a Shear Stress Diffractometer (RHEODYN SSD, Myrenne, Roetgen, Germany). Experiments were carried out on 46 healthy human subjects. The elongation index EI of normal and hardened RBCs (obtained by heating blood at 49 degrees C or by incubating RBCs in solutions of diamide) was measured. The results showed that the standard deviations of the experimental data for normal RBCs were relatively small, especially at high shear stresses (more than 3.0 Pa), but higher than those reported before. Some correlations between the results given by the two instruments were also found. It should be noted that for hardened RBCs, the standard deviations of the measurements were important compared with the mean values in the two instruments.

  7. Measurement of angular parameters of divergent optical radiation by light diffraction on sound

    SciTech Connect

    Kotov, V M; Averin, S V; Shkerdin, G N

    2010-12-09

    A method is proposed to measure the scattering angle of optical radiation, the method employing two Bragg diffraction processes in which divergent optical radiation propagates close to the optical axis of a uniaxial crystal, while the acoustic wave - orthogonally to this axis. The method does not require additional angular tuning of the acousto-optic cell. We suggest using a mask to measure the light divergence that is larger than the angle of Bragg scattering. The method can be used to measure the size of the polished glass plate inhomogeneities. (laser applications and other aspects of quantum electronics)

  8. Exploring the Diffraction Grating Using a He-Ne Laser and a CD-ROM.

    ERIC Educational Resources Information Center

    Tellinghuisen, Joel

    2002-01-01

    A compact disc (CD) serves as a diffraction grating for the study of the dependence of angles of diffracted beams on that of the incident beam from a laser. The demonstration/experiment illustrates the occurrence of different orders of diffraction. Knowledge of the wavelength of the laser permits determination of the groove spacing within ~1% by…

  9. Excimer laser ablation lithography applied to the fabrication of reflective diffractive optics

    NASA Astrophysics Data System (ADS)

    Flury, M.; Benatmane, A.; Gérard, P.; Montgomery, P. C.; Fontaine, J.; Engel, T.; Schunck, J. P.; Fogarassy, E.

    2003-03-01

    We propose a low cost technique for the production of diffractive optical elements (DOE). These elements are devoted to high power lasers beam shaping in the mid-infrared wavelengths. This process called laser ablation lithography (LAL), may seem similar to laser beam writing (LBW) in the way the whole DOE's design is reproduced pixel by pixel on the substrate placed on a computer controlled XY translation stage. A first difference is that the photoresist is not exposed with UV light but is directly ablated with short excimer laser pulses. Furthermore, with LAL technique the size of the smallest pixel ( 5 μm×5 μm) is more than 10 times greater than those produced by LBW. We discuss in details the experimental set-up for LAL and demonstrate that it gives a resolution up to 10 times greater than photolithography with flexible masks. This makes LAL a promising solution for the production of DOE for use with Nd:YAG lasers. New applications of DOEs are finally introduced with high power lasers sources, such as laser marking or multi-point brazing.

  10. On the problem of the diffraction pattern visibility in laser diffractometry of red blood cells

    SciTech Connect

    Nikitin, Sergei Yu; Lugovtsov, Andrei E; Priezzhev, A V

    2011-01-24

    We consider the problem of the visibility of the diffraction pattern that is observed in scattering laser radiation on the erythrocyte suspension in ectacytometer. The theoretical estimates show that 10% variation in the particle size reduces the diffraction pattern visibility by 1% only. (application of lasers and laser-optical methods in life sciences)

  11. Combined Hydrodynamic and Diffraction Simulations of Femtosecond X-ray Scattering from Laser-Shocked Crystals

    NASA Astrophysics Data System (ADS)

    Wark, Justin S.; Higginbotham, Andrew; Milathianaki, Despina; Gleason, Arianna

    2014-05-01

    We describe a simple hydrocode based on a two-step integration scheme that models the evolution of elastic and plastic strains in crystals subject to rapid laser-shock loading. By monitoring the elastic strains during plastic flow we track the rotation and spacing of lattice planes within the polycrystalline sample, and can thus predict the signal that would be produced by x-ray diffraction in a variety of experimental geometries. By employing a simple Taylor-Orowan dislocation model we simulate diffraction patterns in a Debye-Scherrer geometry to track the orthogonal strain states within a laser-shocked sample. The yielding rate is approximately matched to those observed in multi-million atom molecular dynamics (MD) simulations, allowing movies to be made of the diffraction images that would be seen in a real experimental geometry, and illustrating the pertinent experimental requirements, including target texture. Judicious choice of geometry allows clear demarcation of the initial elastic response of the target to be made from the subsequent plastic relaxation. We discuss the simulations in the context of the novel experimental capabilities that have recently become available with the advent of 4th generation light sources, which allow single-shot diffraction with sub-100-fsec resolution.

  12. Combined Hydrodynamic and Diffraction Simulations of Femtosecond X-Ray Scattering from Laser-Shocked Crystals

    NASA Astrophysics Data System (ADS)

    Wark, Justin; Higginbotham, Andrew; Milathianaki, Despina; Gleason, Arianna

    2013-06-01

    We describe a simple hydrocode based on a two-step integration scheme that models the evolution of elastic and plastic strains in crystals subject to rapid laser-shock loading. By monitoring the elastic strains during plastic flow we track the rotation and spacing of lattice planes within the polycrystalline sample, and can thus predict the signal that would be produced by X-ray diffraction in a variety of experimental geometries. By employing a simple Taylor-Orowan dislocation model we simulate diffraction patterns from in a Debye-Scherrer geometry to track the orthogonal strain states within a laser-shocked sample. The yielding rate is approximately matched to those observed in multi-million atom MD simulations, allowing movies to be made of the diffraction images that would be seen in a real experimental geometry, and illustrating the pertinent experimental requirements, including target texture. Judicious choice of geometry allows clear demarcation of the initial elastic response of the target to be made from the subsequent plastic relaxation. We discuss the simulations in the context of the novel experimental capabilities that have recently become available with the advent of 4th generation light sources, which allow single-shot diffraction with sub-100-fs resolution.

  13. Fluctuations of optical phase of diffracted light for Raman-Nath diffraction in acousto-optic effect

    NASA Astrophysics Data System (ADS)

    Cun-Cheng, Weng; Zhang, Xiao-Man

    2015-01-01

    The Raman-Nath diffraction in acousto-optic effect was studied theoretically and experimentally in the paper. Up to now, each order of diffracted light in Raman-Nath diffraction was still considered simply to be just frequency-shifted and to be a plane wave. However, we find that the phase and frequency shifts occur simultaneously and individually in Raman-Nath diffraction. The findings demonstrate that, in addition to the frequency shift, the optical phase of each order of diffracted light is also shifted by the sound wave and fluctuates with the sound wave and is related to the location in the acoustic field from which the diffracted light originates. As a result, the wavefront of each order of diffracted light is modulated to fluctuate spatially and temporally with the sound wave. Obviously, these findings are significant for applications of Raman-Nath diffraction in acousto-optic effect because the optical phase plays an important role in optical coherence technology. Project supported by the National Natural Science Foundation of China (Grant No. 61178089) and the Science and Technology Program of the Educational Office of Fujian Province of China (Grant Nos. JB12012 and JB13003).

  14. Analysis of erythrocyte flexibility by means of laser diffraction: effects of mechanical stress, photosensitization, and ozone

    NASA Astrophysics Data System (ADS)

    Bayer, Rainer; Caglayan, Serdar; Moser, Joerg G.

    1993-07-01

    A newly developed system to determine red blood cell (RBC) flexibility is presented. It combines ektacytometry (laser diffraction) with image analysis. Laser light is passed through erythrocyte (RBC) suspensions which are sheared in a Searle like viscosimeter. The laser diffraction patterns are photographed by a linear CCD camera, and further analyzed by a computer. Flexibility is characterized by the quotient of minor and major axes of isointensity lines of the elliptically transformed diffraction patterns. The variation coefficient of the measurement is less than 1%. Exposing RBC to mechanical stress within the viscosimeter (shear rates from 130 to 2620/s, viscosity of the suspending medium 22 - 24 cpoise) is followed by a decrease of RBC flexibility. This effect is only detectable if elongation is measured at low shear rates (e.g., 260/s) and a threshold of stress (1100/s) is exceeded. It is not reversible and not accompanied with detectable hemolysis. Exposing whole blood to ozone (2 - 77 (mu) g/ml) does not alter RBC flexibility, but induces significant hemolysis at ozone > 7 (mu) g/ml. Thus the action of ozone can be regarded as an all or nothing effect either leaving the cell unaffected (flexibility) or destroying it (hemolysis).

  15. Explosive laser light initiation of propellants

    DOEpatents

    Piltch, M.S.

    1993-05-18

    A improved initiator for artillery shell using an explosively generated laser light to uniformly initiate the propellent. A small quantity of a high explosive, when detonated, creates a high pressure and temperature, causing the surrounding noble gas to fluoresce. This fluorescence is directed into a lasing material, which lases, and directs laser light into a cavity in the propellant, uniformly initiating the propellant.

  16. Explosive laser light initiation of propellants

    DOEpatents

    Piltch, Martin S.

    1993-01-01

    A improved initiator for artillery shell using an explosively generated laser light to uniformly initiate the propellent. A small quantity of a high explosive, when detonated, creates a high pressure and temperature, causing the surrounding noble gas to fluoresce. This fluorescence is directed into a lasing material, which lases, and directs laser light into a cavity in the propellant, uniformly initiating the propellant.

  17. Super-resolution optical telescopes with local light diffraction shrinkage.

    PubMed

    Wang, Changtao; Tang, Dongliang; Wang, Yanqin; Zhao, Zeyu; Wang, Jiong; Pu, Mingbo; Zhang, Yudong; Yan, Wei; Gao, Ping; Luo, Xiangang

    2015-01-01

    Suffering from giant size of objective lenses and infeasible manipulations of distant targets, telescopes could not seek helps from present super-resolution imaging, such as scanning near-field optical microscopy, perfect lens and stimulated emission depletion microscopy. In this paper, local light diffraction shrinkage associated with optical super-oscillatory phenomenon is proposed for real-time and optically restoring super-resolution imaging information in a telescope system. It is found that fine target features concealed in diffraction-limited optical images of a telescope could be observed in a small local field of view, benefiting from a relayed metasurface-based super-oscillatory imaging optics in which some local Fourier components beyond the cut-off frequency of telescope could be restored. As experimental examples, a minimal resolution to 0.55 of Rayleigh criterion is obtained, and imaging complex targets and large targets by superimposing multiple local fields of views are demonstrated as well. This investigation provides an access for real-time, incoherent and super-resolution telescopes without the manipulation of distant targets. More importantly, it gives counterintuitive evidence to the common knowledge that relayed optics could not deliver more imaging details than objective systems. PMID:26677820

  18. Super-resolution optical telescopes with local light diffraction shrinkage

    PubMed Central

    Wang, Changtao; Tang, Dongliang; Wang, Yanqin; Zhao, Zeyu; Wang, Jiong; Pu, Mingbo; Zhang, Yudong; Yan, Wei; Gao, Ping; Luo, Xiangang

    2015-01-01

    Suffering from giant size of objective lenses and infeasible manipulations of distant targets, telescopes could not seek helps from present super-resolution imaging, such as scanning near-field optical microscopy, perfect lens and stimulated emission depletion microscopy. In this paper, local light diffraction shrinkage associated with optical super-oscillatory phenomenon is proposed for real-time and optically restoring super-resolution imaging information in a telescope system. It is found that fine target features concealed in diffraction-limited optical images of a telescope could be observed in a small local field of view, benefiting from a relayed metasurface-based super-oscillatory imaging optics in which some local Fourier components beyond the cut-off frequency of telescope could be restored. As experimental examples, a minimal resolution to 0.55 of Rayleigh criterion is obtained, and imaging complex targets and large targets by superimposing multiple local fields of views are demonstrated as well. This investigation provides an access for real-time, incoherent and super-resolution telescopes without the manipulation of distant targets. More importantly, it gives counterintuitive evidence to the common knowledge that relayed optics could not deliver more imaging details than objective systems. PMID:26677820

  19. Super-resolution optical telescopes with local light diffraction shrinkage

    NASA Astrophysics Data System (ADS)

    Wang, Changtao; Tang, Dongliang; Wang, Yanqin; Zhao, Zeyu; Wang, Jiong; Pu, Mingbo; Zhang, Yudong; Yan, Wei; Gao, Ping; Luo, Xiangang

    2015-12-01

    Suffering from giant size of objective lenses and infeasible manipulations of distant targets, telescopes could not seek helps from present super-resolution imaging, such as scanning near-field optical microscopy, perfect lens and stimulated emission depletion microscopy. In this paper, local light diffraction shrinkage associated with optical super-oscillatory phenomenon is proposed for real-time and optically restoring super-resolution imaging information in a telescope system. It is found that fine target features concealed in diffraction-limited optical images of a telescope could be observed in a small local field of view, benefiting from a relayed metasurface-based super-oscillatory imaging optics in which some local Fourier components beyond the cut-off frequency of telescope could be restored. As experimental examples, a minimal resolution to 0.55 of Rayleigh criterion is obtained, and imaging complex targets and large targets by superimposing multiple local fields of views are demonstrated as well. This investigation provides an access for real-time, incoherent and super-resolution telescopes without the manipulation of distant targets. More importantly, it gives counterintuitive evidence to the common knowledge that relayed optics could not deliver more imaging details than objective systems.

  20. Super-resolution optical telescopes with local light diffraction shrinkage.

    PubMed

    Wang, Changtao; Tang, Dongliang; Wang, Yanqin; Zhao, Zeyu; Wang, Jiong; Pu, Mingbo; Zhang, Yudong; Yan, Wei; Gao, Ping; Luo, Xiangang

    2015-12-18

    Suffering from giant size of objective lenses and infeasible manipulations of distant targets, telescopes could not seek helps from present super-resolution imaging, such as scanning near-field optical microscopy, perfect lens and stimulated emission depletion microscopy. In this paper, local light diffraction shrinkage associated with optical super-oscillatory phenomenon is proposed for real-time and optically restoring super-resolution imaging information in a telescope system. It is found that fine target features concealed in diffraction-limited optical images of a telescope could be observed in a small local field of view, benefiting from a relayed metasurface-based super-oscillatory imaging optics in which some local Fourier components beyond the cut-off frequency of telescope could be restored. As experimental examples, a minimal resolution to 0.55 of Rayleigh criterion is obtained, and imaging complex targets and large targets by superimposing multiple local fields of views are demonstrated as well. This investigation provides an access for real-time, incoherent and super-resolution telescopes without the manipulation of distant targets. More importantly, it gives counterintuitive evidence to the common knowledge that relayed optics could not deliver more imaging details than objective systems.

  1. Laser device for special light effects

    NASA Astrophysics Data System (ADS)

    Gajda, Jerzy K.; Niesterowicz, Andrzej

    1995-03-01

    A system for laser beam deflection and its particular application described in this paper can be treated as a technical aid for contemporary art and visual enhancement of electronic music equipment. The device for special art effects produced by `Optocyfronika' was ordered by disco-clubs. The equipment was designed to enhance light effects with images obtained by means of laser light. One of the results of this work is the device for drawing of simple images by means of the laser beam.

  2. Laser light propagation in adipose tissue and laser effects on adipose cell membranes

    NASA Astrophysics Data System (ADS)

    Solarte, Efraín; Rebolledo, Aldo; Gutierrez, Oscar; Criollo, William; Neira, Rodrigo; Arroyave, José; Ramírez, Hugo

    2006-01-01

    Recently Neira et al. have presented a new liposuction technique that demonstrated the movement of fat from inside to outside of the cell, using a low-level laser device during a liposuction procedure with Ultrawet solution. The clinical observations, allowed this new surgical development, started a set of physical, histological and pharmacological studies aimed to determine the mechanisms involved in the observed fat mobilization concomitant to external laser application in liposuction procedures. Scanning and Transmission Electron Microscopy, studies show that the cellular arrangement of normal adipose tissue changes when laser light from a diode laser: 10 mW, 635 nm is applied. Laser exposures longer than 6 minutes cause the total destruction of the adipocyte panicles. Detailed observation of the adipose cells show that by short irradiation times (less than four minutes) the cell membrane exhibits dark zones, that collapse by longer laser exposures. Optical measurements show that effective penetration length depends on the laser intensity. Moreover, the light scattering is enhanced by diffraction and subsequent interference effects, and the tumescent solution produces a clearing of the tissue optical medium. Finally, isolate adipose cell observation show that fat release from adipocytes is a concomitant effect between the tumescent solution (adrenaline) and laser light, revealing a synergism which conduces to the aperture, and maybe the disruption, of the cell membrane. All these studies were consistent with a laser induced cellular process, which causes fat release from inside the adipocytes into the intercellular space, besides a strong modification of the cellular membranes.

  3. Method and apparatus for reducing diffraction-induced damage in high power laser amplifier systems

    DOEpatents

    Campillo, Anthony J.; Newnam, Brian E.; Shapiro, Stanley L.; Terrell, Jr., N. James

    1976-01-01

    Self-focusing damage caused by diffraction in laser amplifier systems may be minimized by appropriately tailoring the input optical beam profile by passing the beam through an aperture having a uniform high optical transmission within a particular radius r.sub.o and a transmission which drops gradually to a low value at greater radii. Apertures having the desired transmission characteristics may readily be manufactured by exposing high resolution photographic films and plates to a diffuse, disk-shaped light source and mask arrangement.

  4. Correlation between the light diffraction pattern and the structure of a muscle fibre realized with Ewald's construction.

    PubMed

    Zite-Ferenczy, F; Häberle, K D; Rüdel, R; Wilke, W

    1986-06-01

    Ewald's construction of reciprocal space is used to explain the diffraction pattern obtained by illumination of a skeletal muscle fibre with laser light. The question of whether the illuminated fibre segment acts as a monocrystal or as a conglomerate of crystallites is answered by determining the longitudinal extension of the layer lines; neither the whole muscle fibre nor the single myofibril acts as the diffracting unit. The characteristic fine structure within a layer line ('streaks') is explained by Ewald's formalism as being caused by diffraction from partial volumes of the illuminated fibre segment. These partial volumes constitute the main diffracting units. Any cross-section of a 100 micron diameter fibre contains 3-6 such units. They are delineated from each other by the skew of the diffracting planes with respect to the fibre axis, and possibly by small differences in sarcomere length. Within a unit, skew angle and sarcomere length are nearly constant. Light intensity measurements along the length of a layer line at various tilt angles (omega) between fibre and beam axis provide an overview of the size and the skew angle of the various diffracting units within the illuminated fibre segment. The cross-sections of the diffracting units were measured in 'mini'-omega-scans of streaks created by them and from the maximal streak length. In general, the units had noncircular cross-section, the length of the main axis ranging between 10 micron and the fibre diameter. The axial extensions of the diffracting units determined in fibre length scans was 100-300 micron. The results of diffraction experiments reported in the literature as well as the data from light and electron microscopy are in agreement with the fibre structure suggested above. Sarcomere length determination by light diffractometry is discussed within the framework of the Ewald formalism, and recommendations for an experimental procedure are given.

  5. Anomalous behaviors of the Fraunhofer diffraction patterns for a class of partially coherent light.

    PubMed

    Pu, Jixiong; Nemoto, Shojiro

    2003-02-24

    In this paper, we investigate the Fraunhofer diffraction of a class of partially coherent light diffracted by a circular aperture. It is shown that by the illumination of partially coherent light of the special spatial correlation function, the anomalous behaviors of the diffraction patterns are found. We find that the decrease of the spatial coherence of the light in the aperture leads to the drastic changes of the diffraction pattern. Specifically, when the light in the aperture is fully coherent, the diffraction pattern is just an Airy disc. However, as the coherence decreases, the diffraction pattern becomes an annulus, and the radius of the annulus increases with the decrease of the coherence. Flattened annuli can be achieved, when the parameters characterizing the correlation of the partially coherent light are chosen with suitable values. Potential applications of modulating the coherence to achieve desired diffraction patterns are discussed.

  6. Polarization gating enables sarcomere length measurements by laser diffraction in fibrotic muscle

    NASA Astrophysics Data System (ADS)

    Young, Kevin W.; Dayanidhi, Sudarshan; Lieber, Richard L.

    2014-11-01

    Sarcomere length is a key parameter commonly measured in muscle physiology since it dictates striated muscle active force. Laser diffraction (LD)-based measurements of sarcomere length are time-efficient and sample a greater number of sarcomeres compared with traditional microscopy-based techniques. However, a limitation to LD techniques is that signal quality is severely degraded by scattering events as photons propagate through tissue. Consequently, sarcomere length measurements are unattainable when the number of scattering events is sufficiently large in muscle tissue with a high scattering probability. This occurs in fibrotic skeletal muscle seen in muscular dystrophies and secondary to tissue trauma, thus eliminating the use of LD to study these skeletal muscle ailments. Here, we utilize polarization gating to extract diffracted signals that are buried in noise created by scattering. Importantly, we demonstrate that polarization-gated laser diffraction (PGLD) enables sarcomere length measurements in muscles from chronically immobilized mice hind limbs; these muscles have a substantial increase of intramuscular connective tissue that scatter light and disable sarcomere length measurements by traditional LD. Further, we compare PGLD sarcomere lengths to those measured by bright field (BF) and confocal microscopy as positive controls and reveal a significant bias of BF but not of confocal microscopy.

  7. COMPONENTS OF LASER SYSTEMS: Diffraction gratings with high optical strength for laser resonators

    NASA Astrophysics Data System (ADS)

    Svakhin, A. S.; Sychugov, V. A.; Tikhomirov, A. E.

    1994-03-01

    A new approach to the fabrication of efficient diffraction gratings of the reflection type with a high optical strength is proposed. A diffraction grating with an efficiency of 64% was made and used in a resonator of a Q-switched YAG : Nd3+ laser. Gratings of this type are capable of withstanding the action of pulsed optical radiation right up to a power density of 180 MW cm-2. Possible use of such gratings at high angles of incidence of radiation so as to improve the spectral selectivity is considered.

  8. Mesoscale morphology of airborne core-shell nanoparticle clusters: x-ray laser coherent diffraction imaging

    NASA Astrophysics Data System (ADS)

    Pedersoli, E.; Loh, N. D.; Capotondi, F.; Y Hampton, C.; Sierra, R. G.; Starodub, D.; Bostedt, C.; Bozek, J.; Nelson, A. J.; Aslam, M.; Li, S.; Dravid, V. P.; Martin, A. V.; Aquila, A.; Barty, A.; Fleckenstein, H.; Gumprecht, L.; Liang, M.; Nass, K.; Schulz, J.; White, T. A.; Coppola, N.; Bajt, S.; Barthelmess, M.; Graafsma, H.; Hirsemann, H.; Wunderer, C.; Epp, S. W.; Erk, B.; Rudek, B.; Rudenko, A.; Foucar, L.; Kassemeyer, S.; Lomb, L.; Rolles, D.; Shoeman, R. L.; Steinbrener, J.; Hartmann, R.; Hartmann, A.; Hauser, G.; Holl, P.; Kimmel, N.; Reich, C.; Soltau, H.; Weidenspointner, G.; Benner, W. H.; Farquar, G. R.; Hau-Riege, S. P.; Hunter, M. S.; Ekeberg, T.; Hantke, M.; Maia, F. R. N. C.; Tobias, H. J.; Marchesini, S.; Frank, M.; Strüder, L.; Schlichting, I.; Ullrich, J.; Chapman, H. N.; Bucksbaum, P. H.; Kiskinova, M.; Bogan, M. J.

    2013-08-01

    Unraveling the complex morphology of functional materials like core-shell nanoparticles and its evolution in different environments is still a challenge. Only recently has the single-particle coherent diffraction imaging (CDI), enabled by the ultrabright femtosecond free-electron laser pulses, provided breakthroughs in understanding mesoscopic morphology of nanoparticulate matter. Here, we report the first CDI results for Co@SiO2 core-shell nanoparticles randomly clustered in large airborne aggregates, obtained using the x-ray free-electron laser at the Linac Coherent Light Source. Our experimental results compare favourably with simulated diffraction patterns for clustered Co@SiO2 nanoparticles with ˜10 nm core diameter and ˜30 nm shell outer diameter, which confirms the ability to resolve the mesoscale morphology of complex metastable structures. The findings in this first morphological study of core-shell nanomaterials are a solid base for future time-resolved studies of dynamic phenomena in complex nanoparticulate matter using x-ray lasers.

  9. Photoelectron diffraction from laser-aligned molecules with X-ray free-electron laser pulses

    PubMed Central

    Nakajima, Kyo; Teramoto, Takahiro; Akagi, Hiroshi; Fujikawa, Takashi; Majima, Takuya; Minemoto, Shinichirou; Ogawa, Kanade; Sakai, Hirofumi; Togashi, Tadashi; Tono, Kensuke; Tsuru, Shota; Wada, Ken; Yabashi, Makina; Yagishita, Akira

    2015-01-01

    We report on the measurement of deep inner-shell 2p X-ray photoelectron diffraction (XPD) patterns from laser-aligned I2 molecules using X-ray free-electron laser (XFEL) pulses. The XPD patterns of the I2 molecules, aligned parallel to the polarization vector of the XFEL, were well matched with our theoretical calculations. Further, we propose a criterion for applying our molecular-structure-determination methodology to the experimental XPD data. In turn, we have demonstrated that this approach is a significant step toward the time-resolved imaging of molecular structures. PMID:26369428

  10. 32 TW atmospheric white-light laser

    NASA Astrophysics Data System (ADS)

    Béjot, P.; Bonacina, L.; Extermann, J.; Moret, M.; Wolf, J. P.; Ackermann, R.; Lascoux, N.; Salamé, R.; Salmon, E.; Kasparian, J.; Bergé, L.; Champeaux, S.; Guet, C.; Blanchot, N.; Bonville, O.; Boscheron, A.; Canal, P.; Castaldi, M.; Hartmann, O.; Lepage, C.; Marmande, L.; Mazataud, E.; Mennerat, G.; Patissou, L.; Prevot, V.; Raffestin, D.; Ribolzi, J.

    2007-04-01

    Ultrahigh power laser pulses delivered by the Alisé beamline (26J, 32TW pulses) have been sent vertically into the atmosphere. The highly nonlinear propagation of the beam in the air gives rise to more than 400 self-guided filaments. This extremely powerful bundle of laser filaments generates a supercontinuum propagating up to the stratosphere, beyond 20km. This constitutes the highest power "atmospheric white-light laser" to date.

  11. Electronic Rotator For Sheet Of Laser Light

    NASA Technical Reports Server (NTRS)

    Franke, John M.; Rhodes, David B.; Leighty, Bradley D.; Jones, Stephen B.

    1989-01-01

    Primary flow-visualization system in Basic Aerodynamic Research Tunnel (BART) at NASA Langley Research Center is sheet of laser light generated by 5-W argon-ion laser and two-axis mirror galvanometer scanner. Generates single and multiple sheets of light, which remain stationary or driven to sweep out volume. Sine/cosine potentiometer used to orient two galvanometer/mirror devices simultaneously and yields desired result at reasonable cost and incorporated into prototype in 1 day.

  12. Influence of HCl pretreatment on laser diffraction measurements

    NASA Astrophysics Data System (ADS)

    Schulte, Philipp; Steininger, Florian; Lockot, Gregori; Lehmkuhl, Frank; Stauch, Georg; Protze, Jens; Fischer, Peter

    2014-05-01

    Sample pretreatment methods in grain size (GS) analyses differ and their influence on GS distributions has been subject of controversial discussions. The standard sample preparation usually comprises the disaggregation into single primary particles. The organic binding material is oxidized by hydrogen peroxide (H2O2) and the containing carbonates are dissolved by hydrochloric acid (HCl). However, laser diffraction measurements of calcified sediment sequences or sediments with high contents of organic matter show non-reproducible changes in the GS distribution. To investigate variations of the GS distribution, selected samples from two different sections in different stages of weathering and sedimentary genesis were measured using a Beckman Coulter LS13320 laser particle size analyser. A high-resolution Holocene sandy loess-paleosol sequence, the Suohuduo section on the eastern margin of the Tibetan Plateau, was investigated. The results were compared with a Pleistocene loess sequence from the Lower Rhine Embayment, the Düsseldorf-Grafenberg section. The entire sample set includes samples of siliciclastic, barely weathered material and sediments from paleosols. The paleosols in the Suohudo section are strongly influenced by steppe fires and are rich in organo-mineral associations and pyrogenic carbon. All samples were pretreated with hydrogen peroxide and sodium pyrophosphate. In order to investigate the influence of HCl on the GS distribution, the samples were subsequently prepared with and without the addition of HCl. The results show that the sample preparation has a significant influence on the detected GS distribution. Hence, prior to the measurement of a sample set, the effectiveness of the pretreatment argents HCl and H2O2 should be evaluated. In order to generate a valid GS distribution, the sample pretreatment must be matched to the aim of the study and the composition of the sample. Paleoclimatic and environmental interpretation based on improper GS

  13. Reinjection of transmitted laser light into laser-produced plasma for efficient laser ignition.

    PubMed

    Endo, Takuma; Takenaka, Yuhei; Sako, Yoshiyuki; Honda, Tomohisa; Johzaki, Tomoyuki; Namba, Shinichi

    2016-02-10

    For improving the laser absorption efficiency in laser ignition, the transmitted laser light was returned to the laser-produced plasma by using a corner cube. In the experiments, the transmitted light was reinjected into the plasma at different times. The laser absorption efficiency was found to be substantially improved when the transmitted light was reinjected into the plasma after adequate plasma expansion. Furthermore, through visualization experiments on gas-dynamics phenomena, it was found that the reinjection of the transmitted light affected not only the laser absorption efficiency but also the gas dynamics after breakdown, and thereby the initial flame kernel development. PMID:26906388

  14. Engineering Light: Quantum Cascade Lasers

    SciTech Connect

    Claire Gmachl

    2010-03-17

    Quantum cascade lasers are ideal for environmental sensing and medical diagnostic applications. Gmachl discusses how these lasers work, and their applications, including their use as chemical trace gas sensors. As examples of these applications, she briefly presents results from her field campaign at the Beijing Olympics, and ongoing campaigns in Texas, Maryland, and Ghana.

  15. Engineering Light: Quantum Cascade Lasers

    ScienceCinema

    Claire Gmachl

    2016-07-12

    Quantum cascade lasers are ideal for environmental sensing and medical diagnostic applications. Gmachl discusses how these lasers work, and their applications, including their use as chemical trace gas sensors. As examples of these applications, she briefly presents results from her field campaign at the Beijing Olympics, and ongoing campaigns in Texas, Maryland, and Ghana.

  16. Diffraction-dependent spin splitting in spin Hall effect of light on reflection.

    PubMed

    Qiu, Xiaodong; Xie, Linguo; Qiu, Jiangdong; Zhang, Zhiyou; Du, Jinglei; Gao, Fuhua

    2015-07-27

    We report on a diffraction-dependent spin splitting of the paraxial Gaussian light beams on reflection theoretically and experimentally. In the case of horizontal incident polarization, the spin splitting is proportional to the diffraction length of light beams near the Brewster angle. However, the spin splitting is nearly independent with the diffraction length for the vertical incident polarization. By means of the angular spectrum theory, we find that the diffraction-dependent spin splitting is attributed to the first order expansion term of the reflection coefficients with respect to the transverse wave-vector which is closely related to the diffraction length.

  17. Polarization states of diffracted light. Changes accompanying fiber activation.

    PubMed Central

    Chen, J S; Baskin, R J; Baskin, R J; Burton, K; Shen, S; Yeh, Y

    1989-01-01

    Measurement of the state of optical polarization of light diffracted from single, skinned and intact fibers of anterior tibialis muscle from Rana pipiens revealed a dependence upon rigor, activation, and sarcomere length (SL) change. Changes in total birefringence, delta nT, and differential field ratio value, rT, were determined. In a relaxed, skinned fiber the total birefringence value, delta nT, decreases as sarcomere length is increased from 2.1 microns to approximately 2.8-3.0 microns. From there it increases significantly to a value of approximately 1.8 x 10(-3) at a sarcomere length of 3.6 microns. The differential field ratio, rT, also shows a biphasic response to increasing sarcomere length, first exhibiting a rapid decrease over shorter SL and leveling out after the SL is beyond 3.0 microns. In comparison, relaxed intact fibers change substantially less upon sarcomere length change, showing little change in birefringence and a small bi-phasic change in rT. Skinned fibers were activated using a solution that has the same ionic strength as the relaxing solution and allows repeatable, and sustained activation. A decrease in both delta nT and rT was observed upon fiber activation. The decrease in delta nT and rT was slightly larger at shorter sarcomere lengths than at longer lengths. Relaxed fibers placed in rigor showed changes in delta nT and rT similar to those observed in activated fibers. These results are consistent with the hypothesis that, after activation, a significant portion of the thick filament cross-bridges rotate towards the actin filament resulting in redistribution of the interfilament mass content. They are also consistent with an average orientation of crossbridges in the overlap region different from that in the nonoverlap region. PMID:2790140

  18. Polarization states of diffracted light. Changes accompanying fiber activation.

    PubMed

    Chen, J S; Baskin, R J; Baskin, R J; Burton, K; Shen, S; Yeh, Y

    1989-09-01

    Measurement of the state of optical polarization of light diffracted from single, skinned and intact fibers of anterior tibialis muscle from Rana pipiens revealed a dependence upon rigor, activation, and sarcomere length (SL) change. Changes in total birefringence, delta nT, and differential field ratio value, rT, were determined. In a relaxed, skinned fiber the total birefringence value, delta nT, decreases as sarcomere length is increased from 2.1 microns to approximately 2.8-3.0 microns. From there it increases significantly to a value of approximately 1.8 x 10(-3) at a sarcomere length of 3.6 microns. The differential field ratio, rT, also shows a biphasic response to increasing sarcomere length, first exhibiting a rapid decrease over shorter SL and leveling out after the SL is beyond 3.0 microns. In comparison, relaxed intact fibers change substantially less upon sarcomere length change, showing little change in birefringence and a small bi-phasic change in rT. Skinned fibers were activated using a solution that has the same ionic strength as the relaxing solution and allows repeatable, and sustained activation. A decrease in both delta nT and rT was observed upon fiber activation. The decrease in delta nT and rT was slightly larger at shorter sarcomere lengths than at longer lengths. Relaxed fibers placed in rigor showed changes in delta nT and rT similar to those observed in activated fibers. These results are consistent with the hypothesis that, after activation, a significant portion of the thick filament cross-bridges rotate towards the actin filament resulting in redistribution of the interfilament mass content. They are also consistent with an average orientation of crossbridges in the overlap region different from that in the nonoverlap region.

  19. Coherent control of atomic beam diffraction by standing light waves

    SciTech Connect

    Dey, Bijoy K.

    2003-02-01

    Quantum interference is shown to deliver a means of regulating the diffraction pattern of a thermal atomic beam interacting with two standing-wave electric fields. Parameters have been identified to enhance the diffraction probability of one momentum component over the others, with specific application to Rb atoms.

  20. Determination of Particle Size by Diffraction of Light

    ERIC Educational Resources Information Center

    Rinard, Phillip M.

    1974-01-01

    Describes a simplified diffraction experiment offered in a workshop with the purpose of illustrating to high school students the relation of science to society. The radii determined for cigarette smoke particles range from 0.2 to 0.5 micrometer in this experiment. Included is a description of the diffraction theory. (CC)

  1. [Dermatological laser- and light treatments of scars].

    PubMed

    Karmisholt, Katrine; Borch, Jakob E; Omland, Silje Haukali; Hædersdal, Merete

    2016-08-01

    Many patients struggle with tender, rigid and erythematous scars. Various modalities are used to treat cutaneous scars and in recent years, laser treatments are emerging as promising procedures. This article describes laser systems used for scar treatment according to scar type, evaluates the highest available level of evidence from randomized controlled trials (RCTs) and introduces a guideline for laser treatment of scars. Twelve RCTs documented effect on acne, burn and surgical scars. It is recommended that laser- and light-based treatments are considered according to the scar type. PMID:27507028

  2. Laser light scattering instrument advanced technology development

    NASA Technical Reports Server (NTRS)

    Wallace, J. F.

    1993-01-01

    The objective of this advanced technology development (ATD) project has been to provide sturdy, miniaturized laser light scattering (LLS) instrumentation for use in microgravity experiments. To do this, we assessed user requirements, explored the capabilities of existing and prospective laser light scattering hardware, and both coordinated and participated in the hardware and software advances needed for a flight hardware instrument. We have successfully breadboarded and evaluated an engineering version of a single-angle glove-box instrument which uses solid state detectors and lasers, along with fiber optics, for beam delivery and detection. Additionally, we have provided the specifications and written verification procedures necessary for procuring a miniature multi-angle LLS instrument which will be used by the flight hardware project which resulted from this work and from this project's interaction with the laser light scattering community.

  3. Beam Size Measurement by Optical Diffraction Radiation and Laser System for Compton Polarimeter

    SciTech Connect

    Liu, Chuyu

    2012-12-31

    Beam diagnostics is an essential constituent of any accelerator, so that it is named as "organs of sense" or "eyes of the accelerator." Beam diagnostics is a rich field. A great variety of physical effects or physical principles are made use of in this field. Some devices are based on electro-magnetic influence by moving charges, such as faraday cups, beam transformers, pick-ups; Some are related to Coulomb interaction of charged particles with matter, such as scintillators, viewing screens, ionization chambers; Nuclear or elementary particle physics interactions happen in some other devices, like beam loss monitors, polarimeters, luminosity monitors; Some measure photons emitted by moving charges, such as transition radiation, synchrotron radiation monitors and diffraction radiation-which is the topic of the first part of this thesis; Also, some make use of interaction of particles with photons, such as laser wire and Compton polarimeters-which is the second part of my thesis. Diagnostics let us perceive what properties a beam has and how it behaves in a machine, give us guideline for commissioning, controlling the machine and indispensable parameters vital to physics experiments. In the next two decades, the research highlight will be colliders (TESLA, CLIC, JLC) and fourth-generation light sources (TESLA FEL, LCLS, Spring 8 FEL) based on linear accelerator. These machines require a new generation of accelerator with smaller beam, better stability and greater efficiency. Compared with those existing linear accelerators, the performance of next generation linear accelerator will be doubled in all aspects, such as 10 times smaller horizontal beam size, more than 10 times smaller vertical beam size and a few or more times higher peak power. Furthermore, some special positions in the accelerator have even more stringent requirements, such as the interaction point of colliders and wigglor of free electron lasers. Higher performance of these accelerators increases the

  4. Teaching Diffraction of Light and Electrons: Classroom Analogies to Classic Experiments

    ERIC Educational Resources Information Center

    Velentzas, Athanasios

    2014-01-01

    Diffraction and interference are phenomena that demonstrate the wave nature of light and of particles. Experiments relating to the diffraction/interference of light can easily be carried out in an educational lab, but it may be impossible to perform experiments involving electrons because of the lack of specialized equipment needed for such…

  5. Efficient photonic reformatting of celestial light for diffraction-limited spectroscopy

    NASA Astrophysics Data System (ADS)

    MacLachlan, D. G.; Harris, R. J.; Gris-Sánchez, I.; Morris, T. J.; Choudhury, D.; Gendron, E.; Basden, A. G.; Spaleniak, I.; Arriola, A.; Birks, T. A.; Allington-Smith, J. R.; Thomson, R. R.

    2016-10-01

    The spectral resolution of a dispersive astronomical spectrograph is limited by the trade-off between throughput and the width of the entrance slit. Photonic guided-wave transitions have been proposed as a route to bypass this trade-off, by enabling the efficient reformatting of incoherent seeing-limited light collected by the telescope into a linear array of single modes: a pseudo-slit which is highly multimode in one axis but diffraction-limited in the dispersion axis of the spectrograph. It is anticipated that the size of a single-object spectrograph fed with light in this manner would be essentially independent of the telescope aperture size. A further anticipated benefit is that such spectrographs would be free of `modal noise', a phenomenon that occurs in high-resolution multimode fibre-fed spectrographs due to the coherent nature of the telescope point-spread-function (PSF). We seek to address these aspects by integrating a multicore fibre photonic lantern with an ultrafast laser inscribed three-dimensional waveguide interconnect to spatially reformat the modes within the PSF into a diffraction-limited pseudo-slit. Using the CANARY adaptive optics (AO) demonstrator on the William Herschel Telescope, and 1530 ± 80 nm stellar light, the device exhibits a transmission of 47 - 53 per cent depending upon the mode of AO correction applied. We also show the advantage of using AO to couple light into such a device by sampling only the core of the CANARY PSF. This result underscores the possibility that a fully-optimised guided-wave device can be used with AO to provide efficient spectroscopy at high spectral resolution.

  6. Blue laser diode (LD) and light emitting diode (LED) applications

    NASA Astrophysics Data System (ADS)

    Bergh, Arpad A.

    2004-09-01

    The family of blue LEDs, edge emitting and surface emitting lasers, enable a number of applications. Blue lasers are used in digital applications such as optical storage in high density DVDs. The resolution of the spot size and hence the storage density is diffraction limited and is inversely proportional to the square of the wavelength of the laser. Other applications include printing, optical scanners, and high-resolution photo-lithography.As light emitters, blue LEDs are used for signaling and in direct view large area emissive displays. They are also making inroads into signage and LCD back-lighting, mobile platforms, and decorative accent lighting in curtains, furniture, etc.Blue LEDs produce white light either with phosphor wavelength converters or in combination with red and green LEDs. The full potential of LED light sources will require three devices to enable complete control over color and intensity.Sensing and medical/bio applications have a major impact on home security, on monitoring the environment, and on health care. New emerging diagnostic and therapeutic applications will improve the quality and reduce the cost of health care.

  7. Application of the maximum entropy technique in tomographic reconstruction from laser diffraction data to determine local spray drop size distribution

    NASA Astrophysics Data System (ADS)

    Yongyingsakthavorn, Pisit; Vallikul, Pumyos; Fungtammasan, Bundit; Dumouchel, Christophe

    2007-03-01

    This work proposes a new deconvolution technique to obtain local drop size distributions from line-of-sight intensity data measured by laser diffraction technique. The tomographic reconstruction, based on the maximum entropy (ME) technique, is applied to forward scattered light signal from a laser beam scanning horizontally through the spray on each plane from the center to the edge of spray, resulting in the reconstructed scattered light intensities at particular points in the spray. These reconstructed intensities are in turn converted to local drop size distributions. Unlike the classical method of the onion peeling technique or other mathematical transformation techniques that yield unrealistic negative scattered light intensity solutions, the maximum entropy constraints ensure positive light intensity. Experimental validations to the reconstructed results are achieved by using phase Doppler particle analyzer (PDPA). The results from the PDPA measurements agree very well with the proposed ME tomographic reconstruction.

  8. Enhanced light extraction efficiency of OLEDs with quasiperiodic diffraction grating layer.

    PubMed

    Lim, Tae-Bin; Cho, Kwan Hyun; Kim, Yong-Hoon; Jeong, Yong-Cheol

    2016-08-01

    We presented enhanced light extraction efficiency of organic light emitting diodes (OLEDs) cells with a nano-sized diffraction grating layer. Various diffraction gratings of different morphologies including linear, cubic, hexagonal and quasiperiodic patterns were fabricated by multiplexing light interference exposure on an azobenzene thin film. The effect of diffraction grating layer on device performances including luminous properties and quantum efficiency was investigated. In contrast to periodic grating patterns, the quasiperiodic structures leading broadband light extraction resulted in improved external quantum efficiency and power efficiency by 73% and 63%, respectively, compared to conventional OLED with flat surface of glass substrate.

  9. Efficient IR Transmission Diffraction Grating for Circularly Polarized Light

    NASA Technical Reports Server (NTRS)

    Cole, Helen; Chambers, Diana

    1999-01-01

    Numerical methods, using rigorous coupled wave theory, are used to design rectangular relief diffraction gratings for an infrared application which requires comparable first order efficiencies in the TE and TM polarization states. The depth, period, and fill factor of the grating are varied to identify optimal two level binary lamellar grating profiles which predict efficiencies for individual TM and TE polarizations above 75 percent, while keeping the difference between the two efficiencies within 10 percent. The application at hand is a rotating, transmissive diffractive scanner for space-based coherent lidar. The operating wavelength is 2.0 microns. A collimated, circularly polarized beam is incident on the diffractive scanner at the Bragg angle; 30 and 45 degree beam deflection angles being studied. Fused silica is the substrate material of choice. Selected designs are fabricated on 3 inch fused silica substrates using lithographic methods. The performance of the test pieces is measured and compared to theoretical predictions.

  10. Zeeman effect induced by intense laser light.

    PubMed

    Stambulchik, E; Maron, Y

    2014-08-22

    We analyze spectral line shapes of hydrogenlike species subjected to fields of electromagnetic waves. It is shown that the magnetic component of an electromagnetic wave may significantly influence the spectra. In particular, the Zeeman effect induced by a visible or infrared light can be experimentally observed using present-day powerful lasers. In addition, the effect may be used for diagnostics of focused beam intensities achieved at existing and newly built laser facilities. PMID:25192094

  11. Zeeman effect induced by intense laser light.

    PubMed

    Stambulchik, E; Maron, Y

    2014-08-22

    We analyze spectral line shapes of hydrogenlike species subjected to fields of electromagnetic waves. It is shown that the magnetic component of an electromagnetic wave may significantly influence the spectra. In particular, the Zeeman effect induced by a visible or infrared light can be experimentally observed using present-day powerful lasers. In addition, the effect may be used for diagnostics of focused beam intensities achieved at existing and newly built laser facilities.

  12. Investigation of stimulated raman scattering using short-pulse diffraction limited laser beam near the instability threshold

    SciTech Connect

    Kline, John L; Montgomery, David S; Flippo, Kirk A; Rose, Harvey A; Yin, L; Albright, B J; Johnson, R P; Shimada, T; Bowers, K; Rousseaux, C; Tassin, V; Baton, S D; Amiranoff, F; Hardin, R A

    2008-01-01

    Short pulse laser plasma interaction experiments using diffraction limited beams provide an excellent platform to investigate the fundamental physics of Stimulated Raman Scattering. Detailed understanding of these laser plasma instabilities impacts the current inertial confinement fusion ignition designs and could potentially impact fast ignition when higher energy lasers are used with longer pulse durations ( > 1 kJ and> 1 ps). Using short laser pulses, experiments can be modeled over the entire interaction time of the laser using particle-in-cell codes to validate our understanding quantitatively. Experiments have been conducted at the Trident laser facility and the LULI (Laboratoire pour l'Utilisation des Lasers Intenses) to investigate stimulated Raman scattering near the threshold of the instability using 527 nm and 1059 nm laser light respectively with 1.5-3.0 ps pulses. In both experiments, the interaction beam was focused into a pre-ionized He gas-jet plasma. Measurements of the reflectivity as a function of intensity and k{lambda}{sub D} were completed at the Trident laser facility. At LULI, a 300 fs Thomson scattering probe is used to directly measure the density fluctuations of the driven electron plasma and ion acoustic waves. Work is currently underway comparing the results of the experiments with simulations using the VPIC [K. J. Bowers, et at., Phys. Plasmas, 15 055703 (2008)] particle-in-cell code. Details of the experimental results are presented in this manuscript.

  13. Spatial optical modulator (SOM): high-density diffractive laser projection display

    NASA Astrophysics Data System (ADS)

    Yun, SangKyeong; Song, JongHyeong; Yeo, InJae; Choi, YoonJoon; Yurlov, Victor; An, SeungDo; Park, HeungWoo; Yang, HaengSeok; Lee, YeongGyu; Han, KyuBum; Shyshkin, Ihar; Lapchuk, Anatoliy; Oh, KwanYoung; Ryu, SeungWon; Jang, JaeWook; Park, ChangSu; Kim, ChunGi; Kim, SunKi; Kim, EungJu; Woo, KiSuk; Yang, JeongSuong; Kim, EuiJoong; Kim, JooHong; Byun, SungHo; Lee, SeungWoo; Lim, OhkKun; Cheong, JongPil; Hwang, YoungNam; Byun, GiYoung; Kyoung, JeHong; Yoon, SangKee; Lee, JaeKwang; Lee, TaeWon; Hong, SeokKee; Hong, YoonShik; Park, DongHyun; Kang, JungChul; Shin, WooChul; Lee, SungIl; Oh, SungKyung; Song, ByungKi; Kim, HeeYeoun; Koh, ChongMann; Ryu, YungHo; Lee, HyunKee; Baek, YoungKi

    2007-02-01

    A new type of diffractive spatial optical modulators, named SOM, has been developed by Samsung Electro-Mechanics for laser projection display. It exhibit inherent advantages of fast response time and high-performance light modulation, suitable for high quality embedded laser projection displays. The calculated efficiency and contrast ratio are 75 % and 800:1 respectively in case of 0 th order, 67 % and 1000:1 respectively in case of +/-1st order. The response time is as fast as 0.7 μs. Also we get the displacement of 400 nm enough to display full color with single panel in VGA format, as being 10 V driven. Optical module with VGA was successfully demonstrated for its potential applications in mobile laser projection display such as cellular phone, digital still camera and note PC product. Electrical power consumption is less than 2 W, volume is less than 13 cc. Brightness is enough to watch TV and movie in the open air, being variable up to 6 lm. Even if it's optimal diagonal image size is 10 inch, image quality does not deteriorate in the range of 5 to 50 inch because of the merit of focus-free. Due to 100 % fill factor, the image is seamless so as to be unpleasant to see the every pixel's partition. High speed of response time can make full color display with 24-bit gray scale and cause no scan line artifact, better than any other devices.

  14. Lasers and Intense Pulsed Light Hidradenitis Suppurativa.

    PubMed

    Saunte, Ditte M; Lapins, Jan

    2016-01-01

    Lasers and intense pulsed light (IPL) treatment are useful for the treatment of hidradenitis suppurativa (HS). Carbon dioxide lasers are used for cutting or vaporization of the affected area. It is a effective therapy for the management of severe and recalcitrant HS with persistent sinus tract and scarring, and can be performed under local anesthesia. HS has a follicular pathogenesis. Lasers and IPL targeting the hair have been found useful in treating HS by reducing the numbers of hairs in areas with HS. The methods have few side effects, but the studies are preliminary and need to be repeated. PMID:26617364

  15. Lasers and Intense Pulsed Light Hidradenitis Suppurativa.

    PubMed

    Saunte, Ditte M; Lapins, Jan

    2016-01-01

    Lasers and intense pulsed light (IPL) treatment are useful for the treatment of hidradenitis suppurativa (HS). Carbon dioxide lasers are used for cutting or vaporization of the affected area. It is a effective therapy for the management of severe and recalcitrant HS with persistent sinus tract and scarring, and can be performed under local anesthesia. HS has a follicular pathogenesis. Lasers and IPL targeting the hair have been found useful in treating HS by reducing the numbers of hairs in areas with HS. The methods have few side effects, but the studies are preliminary and need to be repeated.

  16. Ultrafast coherent X-ray diffractive imaging with the FLASH Free-Electron Laser

    NASA Astrophysics Data System (ADS)

    Chapman, H. N.; Bajt, S.; Barty, A.; Benner, W. H.; Bogan, M. J.; Boutet, S.; Cavalleri, A.; Düsterer, S.; Frank, M.; Hajdu, J.; Hau-Riege, S. P.; Iwan, B.; Marchesini, S.; Sokolowski-Tinten, K.; Siebert, M. M.; Treusch, R.; Woods, B. W.

    High-resolution ultrafast coherent diffractive imaging has been carried out at the FLASH FEL. Reconstructed images show no effect of sample destruction. Time resolved imaging was achieved by time-delay holography and with a synchronized optical laser.

  17. Laser-Modified Black Titanium Oxide Nanospheres and Their Photocatalytic Activities under Visible Light.

    PubMed

    Chen, Xing; Zhao, Dongxu; Liu, Kewei; Wang, Chunrui; Liu, Lei; Li, Binghui; Zhang, Zhenzhong; Shen, Dezhen

    2015-07-29

    A facile pulse laser ablation approach for preparing black titanium oxide nanospheres, which could be used as photocatalysts under visible light, is proposed. The black titanium oxide nanospheres are prepared by pulsed-laser irradiation of pure titanium oxide in suspended aqueous solution. The crystalline phases, morphology, and optical properties of the obtained nanospheres are characterized by means of X-ray diffraction (XRD), field-emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), X-ray photoelectron spectroscopy (XPS), and UV-vis-NIR diffuse reflectance spectroscopy. It is shown that high-energy laser ablation of titanium oxide suspended solution benefited the formation of Ti(3+) species and surface disorder on the surface of the titanium oxide nanospheres. The laser-modified black titanium oxide nanospheres could absorb the full spectrum of visible light, thus exhibiting good photocatalytic performance under visible light.

  18. Diffracted light from latent images in photoresist for exposure control

    DOEpatents

    Bishop, Kenneth P.; Brueck, Steven R. J.; Gaspar, Susan M.; Hickman, Kirt C.; McNeil, John R.; Naqvi, S. Sohail H.; Stallard, Brian R.; Tipton, Gary D.

    1997-01-01

    In microelectronics manufacturing, an arrangement for monitoring and control of exposure of an undeveloped photosensitive layer on a structure susceptible to variations in optical properties in order to attain the desired critical dimension for the pattern to be developed in the photosensitive layer. This is done by ascertaining the intensities for one or more respective orders of diffracted power for an incident beam of radiation corresponding to the desired critical dimension for the photosensitive layer as a function of exposure time and optical properties of the structure, illuminating the photosensitive layer with a beam of radiation of one or more frequencies to which the photosensitive layer is not exposure-sensitive, and monitoring the intensities of the orders of diffracted radiation due to said illumination including at least the first order of diffracted radiation thereof, such that when said predetermined intensities for the diffracted orders are reached during said illumination of photosensitive layer, it is known that a pattern having at least approximately the desired critical dimension can be developed on the photosensitive layer.

  19. CD, DVD, and Blu-Ray Disc Diffraction with a Laser Ray Box

    ERIC Educational Resources Information Center

    DeWeerd, Alan J.

    2016-01-01

    A compact disc (CD) can be used as a diffraction grating, even though its track consists of a series of pits, not a continuous groove. Previous authors described how to measure the track spacing on a CD using an incident laser beam normal to the surface or one at an oblique angle. In both cases, the diffraction pattern was projected on a screen…

  20. Critical femtosecond laser parameters for the fabrication of optimal reflecting diffraction gratings on Invar36

    NASA Astrophysics Data System (ADS)

    Mohammad Hossein, Goudarzi; Meng-Jyun, Lin; Ji-Bin, Horng; Jeng-Ywan, Jeng

    2016-06-01

    This paper discusses the effect of femtosecond laser parameters on Invar36, and the efficiency of reflecting diffraction gratings on the alloy. Several gratings were made with different laser parameters in two regimes: constant repetition rates and constant average laser power on the Invar surface. The efficiency of diffraction gratings is measured in an off-plane configuration by determining the power of diffracted points. With the constant average power technique, an increase in laser influence decreased the ablation depth of lines and increased the line widths. The discoloration of line edges from increasing the laser influence more than 0.57 J /cm2 decreased the grating efficiency by over 49%. It was also found that increasing the repetition rate enhanced the grating efficiency and increasing the average power decreased the efficiency. In addition, the ablation threshold of Invar is 0.122 J /cm2 when the number of pulses (NOP) equals 389.

  1. Doppler shift generated by a moving diffraction grating under incidence by polychromatic diffuse light

    NASA Astrophysics Data System (ADS)

    Dossou, Kokou B.

    2016-05-01

    We consider the spectral response of moving diffraction gratings, in which the incident light extends over a broad angular range and where the diffracted light is observed from a specific angle. We show that the dispersion relation between the frequency perceived by an observer who is looking at a moving grating and the incident frequency can exhibit some unique features, such as a flat band (i.e., a local minimum). An observer can see the light diffracted into a non-specular diffraction order from a multitude of incident light rays and the angle of incidence of each ray is frequency-dependent, as a consequence, when the grating is moving, each incident ray experiences a Doppler shift in frequency that depends on its angle of incidence. We find that remarkable features appear near a Wood anomaly where the angle of incidence, for a given diffraction angle, can change very quickly with frequency. This means that light of multiple frequencies and incident from multiple angles can be mixed by the motion of the grating into the same diffracted ray and their frequencies can be compressed into a narrower range. The existence of a flat band means that a moving grating can be used as a device to increase the intensity of the perceived diffracted light due to spectral compression. The properties of a grating in motion in sunlight can also be relevant to the study of naturally occurring gratings which are typically in oscillatory motion.

  2. Doppler shift generated by a moving diffraction grating under incidence by polychromatic diffuse light.

    PubMed

    Dossou, Kokou B

    2016-05-20

    We consider the spectral response of moving diffraction gratings, in which the incident light extends over a broad angular range and where the diffracted light is observed from a specific angle. We show that the dispersion relation between the frequency perceived by an observer who is looking at a moving grating and the incident frequency can exhibit some unique features, such as a flat band (i.e., a local minimum). An observer can see the light diffracted into a nonspecular diffraction order from a multitude of incident light rays, and the angle of incidence of each ray is frequency dependent; as a consequence, when the grating is moving, each incident ray experiences a Doppler shift in frequency that depends on its angle of incidence. We find that remarkable features appear near a Wood anomaly where the angle of incidence, for a given diffraction angle, can change very quickly with frequency. This means that light of multiple frequencies and incident from multiple angles can be mixed by the motion of the grating into the same diffracted ray and their frequencies can be compressed into a narrower range. The existence of a flat band means that a moving grating can be used as a device to increase the intensity of the perceived diffracted light due to spectral compression. The properties of a grating in motion in sunlight can also be relevant to the study of naturally occurring gratings which are typically in oscillatory motion.

  3. Light scattering by red blood cells in ektacytometry: Fraunhofer versus anomalous diffraction.

    PubMed

    Streekstra, G J; Hoekstra, A G; Nijhof, E J; Heethaar, R M

    1993-05-01

    In the present literature on ektacytometry, small angle light scattering by ellipsoidal red blood cells is commonly approximated by Fraunhofer diffraction. Calculations on a sphere with the size and relative refractive index of a red cell, however, show that Fraunhofer diffraction deviates significantly from exact Mie theory. Anomalous diffraction is found to be a much better approximation. The anomalous diffraction theory is used to calculate the intensity distribution of the light scattered by an ellipsoidally deformed red blood cell. The derived expression shows that the ellipticity of isointensity curves in forward scattered light are equal to the ellipticity of the red blood cell. The theoretical expression is fitted to the intensity patterns measured with an ektacytometer. For the small observation angles used in ektacytometry, the experimental results confirm the validity of the anomalous diffraction approach.

  4. Investigation of Stimulated Raman Scattering Using Short-Pulse Diffraction Limited Laser Beam near the Instability Threshold

    NASA Astrophysics Data System (ADS)

    Kline, J. L.; Montgomery, D. S.; Yin, L.; Flippo, K. A.; Albright, B. J.; Johnson, R. P.; Shimada, T.; Rose, H. A.; Rousseaux, C.; Tassin, V.; Baton, S. D.; Amiranoff, F.; Hardin, R. A.

    2008-11-01

    Short pulse laser plasma interaction experiments using diffraction limited beams provide an excellent platform to investigate the fundamental physics of Stimulated Raman (SRS) and Stimulated Brillouin (SBS) Scattering. Detailed understanding of these laser plasma instabilities impacts the current inertial confinement fusion ignition designs and could potentially impact fast ignition when higher energy lasers are used with longer pulse durations ( > 1 kJ and > 1 ps). Using short laser pulses, experiments can be modeled over the entire interaction time of the laser using PIC codes to validate our understanding. Experiments have been conducted at the Trident laser and the LULI to investigate SRS near the threshold of the instability using 527 and 1064 nm laser light respectively with 1.5 -- 3 ps pulses. In the case of both experiments, the interaction beam was focused into a pre-ionized He gasjet plasma. Measurements of the reflectivity as a function of intensity and k?D were completed at the Trident laser. At LULI, a 300 fs Thomson scattering probe is used to directly measure the density fluctuations of the driven electron plasma and ion acoustic waves. Details of the experimental results will be presented.

  5. The global light system laser station prototype

    NASA Astrophysics Data System (ADS)

    Hunt, Patrick R.

    We describe the design and fabrication of a prototype Global Light System (GLS) laser station for the JEM-EUSO project. The GLS will consist of a network of ground-based Ultraviolet (UV) light-emitting diodes (LEDs) and steered lasers to monitor and calibrate the cosmic ray detector planned for install on the International Space Station (ISS). The GLS units will generate optical signatures in the atmosphere that are comparable to tracks from cosmic ray extensive air showers (EASs). Unlike an EAS, the number, time, energy, location and direction (for lasers) of GLS events can be specified as JEM-EUSO passes 400 km overhead. Laser tracks from the GLS prototype will be recorded by prototype detectors in ground-to-ground tests. Distant tracks with low angular speed are of particular interest because these are the types of EAS tracks that will be measured by JEM-EUSO. To do these ground-to-ground tests, the prototype detectors will need to measure the laser through the atmosphere at low elevation viewing angles. The beam energy can be adjusted from 1 to 90 mJ to compensate for this additional atmospheric attenuation. The frequency-tripled Nd:YAG laser produces 355 nm (7 ns pulse) light. This wavelength is near the center of the UV EAS fluorescence spectrum. The system is housed in a utility trailer that can be transported by a small truck for domestic campaigns or shipped in an industry standard 20 foot container for global deployment. In operation mode, the laser platform inside the trailer is isolated mechanically to maintain beam pointing accuracy. A retractable two stage steering head can point in any direction above the horizon. A slip ring eliminates cable wrap problems. The GLS prototype will be used to test the EUSO-TA detector and will also be used in preflight tests of the EUSO-balloon payload planned for a super pressure balloon mission.

  6. Miniature instrumentation for laser light scattering experiments

    NASA Technical Reports Server (NTRS)

    Brown, Robert G. W.

    1989-01-01

    Traditional optical systems for photon correlation spectroscopy and laser anemometry have relied upon physically large and fairly expensive lasers, bulk-optics such as lenses of a few inches diameter, large mechanical mounts and carefully selected, fragile and bulky photon counting photomultiplier detectors. In some cases, experimental fluid dynamics at a desired position in a flow, perhaps deep inside complex machinery, is physically impossible or very difficult. Similar problems exist with photon correlation spectroscopy, e.g., remote and heterodyne experiments. Various optical and electro optical components were investigated and characterized with the aim of replacing existing photon correlation laser spectroscopy and anemometry techniques in miniaturized form, and with significant cost reduction. Very recently, a range of miniature, modular light scattering systems were constructed from little solid state optical and electro optical components, and experimentally verified measurement performance comparable to standard lab photon correlation spectroscopy and laser anemometry equipment.

  7. High-order diffraction gratings for high-power semiconductor lasers

    SciTech Connect

    Vasil'eva, V. V.; Vinokurov, D. A.; Zolotarev, V. V.; Leshko, A. Yu.; Petrunov, A. N.; Pikhtin, N. A.; Rastegaeva, M. G.; Sokolova, Z. N. Shashkin, I. S.; Tarasov, I. S.

    2012-02-15

    A deep diffraction grating with a large period ({approx}2 {mu}m) within one of the cladding layers is proposed for the implementation of selective feedback in a semiconductor laser. Frequency dependences of reflectance in the 12th diffraction order for rectangular, triangular, and trapezoidal diffraction gratings are calculated. It is shown that the maximum reflectance of the waveguide mode is attained using a rectangular or trapezoidal grating {approx}2 {mu}m deep in the laser structure. Deep trapezoidal diffraction gratings with large periods are fabricated in the Al{sub 0.3}Ga{sub 0.7}As cladding layer of a GaAs/AlGaAs laser structure using photolithography and reactive ion etching.

  8. Diffractive light trapping in crystal-silicon films: experiment and electromagnetic modeling.

    PubMed

    Weiss, Dirk N; Lee, Benjamin G; Richmond, Dustin A; Nemeth, William; Wang, Qi; Keszler, Douglas A; Branz, Howard M

    2011-10-10

    Diffractive light trapping in 1.5 μm thick crystal silicon films is studied experimentally through hemispherical reflection measurements and theoretically through rigorous coupled-wave analysis modeling. The gratings were fabricated by nanoimprinting of dielectric precursor films. The model data, which match the experimental results well without the use of any fitting parameters, are used to extract the light trapping efficiency. Diffractive light trapping is studied as a function of incidence angle, and an enhancement of light absorption is found for incidence angles up to 50° for both TE and TM polarizations.

  9. Analysis of the scalability of diffraction-limited fiber lasers and amplifiers to high average power.

    PubMed

    Dawson, Jay W; Messerly, Michael J; Beach, Raymond J; Shverdin, Miroslav Y; Stappaerts, Eddy A; Sridharan, Arun K; Pax, Paul H; Heebner, John E; Siders, Craig W; Barty, C P J

    2008-08-18

    We analyze the scalability of diffraction-limited fiber lasers considering thermal, non-linear, damage and pump coupling limits as well as fiber mode field diameter (MFD) restrictions. We derive new general relationships based upon practical considerations. Our analysis shows that if the fiber's MFD could be increased arbitrarily, 36 kW of power could be obtained with diffraction-limited quality from a fiber laser or amplifier. This power limit is determined by thermal and non-linear limits that combine to prevent further power scaling, irrespective of increases in mode size. However, limits to the scaling of the MFD may restrict fiber lasers to lower output powers.

  10. Design and fabrication of diffractive microlens arrays with continuous relief for parallel laser direct writing.

    PubMed

    Tan, Jiubin; Shan, Mingguang; Zhao, Chenguang; Liu, Jian

    2008-04-01

    Diffractive microlens arrays with continuous relief are designed, fabricated, and characterized by using Fermat's principle to create an array of spots on the photoresist-coated surface of a substrate for parallel laser direct writing. Experimental results indicate that a diffraction efficiency of 71.4% and a spot size of 1.97 microm (FWHM) can be achieved at normal incidence and a writing laser wavelength of 441.6 nm with an array of F/4 fabricated on fused silica, and the developed array can be used to improve the utilization ratio of writing laser energy. PMID:18382568

  11. Analysis of the scalability of diffraction-limited fiber lasers and amplifiers to high average power.

    PubMed

    Dawson, Jay W; Messerly, Michael J; Beach, Raymond J; Shverdin, Miroslav Y; Stappaerts, Eddy A; Sridharan, Arun K; Pax, Paul H; Heebner, John E; Siders, Craig W; Barty, C P J

    2008-08-18

    We analyze the scalability of diffraction-limited fiber lasers considering thermal, non-linear, damage and pump coupling limits as well as fiber mode field diameter (MFD) restrictions. We derive new general relationships based upon practical considerations. Our analysis shows that if the fiber's MFD could be increased arbitrarily, 36 kW of power could be obtained with diffraction-limited quality from a fiber laser or amplifier. This power limit is determined by thermal and non-linear limits that combine to prevent further power scaling, irrespective of increases in mode size. However, limits to the scaling of the MFD may restrict fiber lasers to lower output powers. PMID:18711562

  12. Temporal pulse cleaning by a self-diffraction process for ultrashort laser pulses

    NASA Astrophysics Data System (ADS)

    Xie, Na; Zhou, Kainan; Sun, Li; Wang, Xiaodong; Guo, Yi; Li, Qing; Su, Jingqin

    2014-11-01

    Applying the self-diffraction process to clean ultrashort laser pulses temporally is a recently developed effective way to temporal contrast enhancement. In this paper, we attempt to clean ultrashort laser pulses temporally by the self-diffraction process. Experiments were carried out to study the temporal contrast improvement in the front-end system of an ultraintense and ultrashort laser facility, i.e. the super intense laser for experiment on the extremes (SILEX-I). The results show that the maximum conversion efficiency of the first-order self-diffraction (SD1) pulse is 11%. The temporal contrast of the SD1 signal is improved by two orders of magnitude, i.e. to 103, for a 2.4-ns prepulse with initial contrast of ~10. For a 5.5 -ns prepulse with initial contrast of 2×103, the temporal contrast of the SD1 signal is improved by more than three orders of magnitude.

  13. 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.

  14. Diffractive optical elements for transformation of modes in lasers

    SciTech Connect

    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.

  15. Femtosecond free-electron laser x-ray diffraction data sets for algorithm development.

    PubMed

    Kassemeyer, Stephan; Steinbrener, Jan; Lomb, Lukas; Hartmann, Elisabeth; Aquila, Andrew; Barty, Anton; Martin, Andrew V; Hampton, Christina Y; Bajt, Saša; Barthelmess, Miriam; Barends, Thomas R M; Bostedt, Christoph; Bott, Mario; Bozek, John D; Coppola, Nicola; Cryle, Max; DePonte, Daniel P; Doak, R Bruce; Epp, Sascha W; Erk, Benjamin; Fleckenstein, Holger; Foucar, Lutz; Graafsma, Heinz; Gumprecht, Lars; Hartmann, Andreas; Hartmann, Robert; Hauser, Günter; Hirsemann, Helmut; Hömke, André; Holl, Peter; Jönsson, Olof; Kimmel, Nils; Krasniqi, Faton; Liang, Mengning; Maia, Filipe R N C; Marchesini, Stefano; Nass, Karol; Reich, Christian; Rolles, Daniel; Rudek, Benedikt; Rudenko, Artem; Schmidt, Carlo; Schulz, Joachim; Shoeman, Robert L; Sierra, Raymond G; Soltau, Heike; Spence, John C H; Starodub, Dmitri; Stellato, Francesco; Stern, Stephan; Stier, Gunter; Svenda, Martin; Weidenspointner, Georg; Weierstall, Uwe; White, Thomas A; Wunderer, Cornelia; Frank, Matthias; Chapman, Henry N; Ullrich, Joachim; Strüder, Lothar; Bogan, Michael J; Schlichting, Ilme

    2012-02-13

    We describe femtosecond X-ray diffraction data sets of viruses and nanoparticles collected at the Linac Coherent Light Source. The data establish the first large benchmark data sets for coherent diffraction methods freely available to the public, to bolster the development of algorithms that are essential for developing this novel approach as a useful imaging technique. Applications are 2D reconstructions, orientation classification and finally 3D imaging by assembling 2D patterns into a 3D diffraction volume.

  16. Femtosecond free-electron laser x-ray diffraction data sets for algorithm development.

    PubMed

    Kassemeyer, Stephan; Steinbrener, Jan; Lomb, Lukas; Hartmann, Elisabeth; Aquila, Andrew; Barty, Anton; Martin, Andrew V; Hampton, Christina Y; Bajt, Saša; Barthelmess, Miriam; Barends, Thomas R M; Bostedt, Christoph; Bott, Mario; Bozek, John D; Coppola, Nicola; Cryle, Max; DePonte, Daniel P; Doak, R Bruce; Epp, Sascha W; Erk, Benjamin; Fleckenstein, Holger; Foucar, Lutz; Graafsma, Heinz; Gumprecht, Lars; Hartmann, Andreas; Hartmann, Robert; Hauser, Günter; Hirsemann, Helmut; Hömke, André; Holl, Peter; Jönsson, Olof; Kimmel, Nils; Krasniqi, Faton; Liang, Mengning; Maia, Filipe R N C; Marchesini, Stefano; Nass, Karol; Reich, Christian; Rolles, Daniel; Rudek, Benedikt; Rudenko, Artem; Schmidt, Carlo; Schulz, Joachim; Shoeman, Robert L; Sierra, Raymond G; Soltau, Heike; Spence, John C H; Starodub, Dmitri; Stellato, Francesco; Stern, Stephan; Stier, Gunter; Svenda, Martin; Weidenspointner, Georg; Weierstall, Uwe; White, Thomas A; Wunderer, Cornelia; Frank, Matthias; Chapman, Henry N; Ullrich, Joachim; Strüder, Lothar; Bogan, Michael J; Schlichting, Ilme

    2012-02-13

    We describe femtosecond X-ray diffraction data sets of viruses and nanoparticles collected at the Linac Coherent Light Source. The data establish the first large benchmark data sets for coherent diffraction methods freely available to the public, to bolster the development of algorithms that are essential for developing this novel approach as a useful imaging technique. Applications are 2D reconstructions, orientation classification and finally 3D imaging by assembling 2D patterns into a 3D diffraction volume. PMID:22418172

  17. Employing partially coherent, compact gas-discharge sources for coherent diffractive imaging with extreme ultraviolet light

    NASA Astrophysics Data System (ADS)

    Bußmann, J.; Odstrčil, M.; Bresenitz, R.; Rudolf, D.; Miao, Jianwei; Brocklesby, W. S.; Grützmacher, D.; Juschkin, L.

    2015-09-01

    Coherent diffractive imaging (CDI) and related techniques enable a new type of diffraction-limited high-resolution extreme ultraviolet (EUV) microscopy. Here, we demonstrate CDI reconstruction of a complex valued object under illumination by a compact gas-discharge EUV light source emitting at 17.3 nm (O VI spectral line). The image reconstruction method accounts for the partial spatial coherence of the radiation and allows imaging even with residual background light. These results are a first step towards laboratory-scale CDI with a gas-discharge light source for applications including mask inspection for EUV lithography, metrology and astronomy.

  18. The nature of light: a description of photon diffraction based upon virtual particle exchange

    NASA Astrophysics Data System (ADS)

    Mobley, Michael J.

    2005-08-01

    Any discussion of the nature of light must include a reminder that whenever we make the observation of light (photons), we only observe particle-like properties. This paper provides a reiteration that we don"t need wave-like properties to scattered photons to describe phenomena such as diffraction or refraction of light. This paper updates the original ideas of Duane, later revived by Lande, which provided a description of light diffraction without making reference to a wave nature. These are updated using terminology more common to quantum electrodynamics which describes the interaction of particles in terms of the exchange of virtual photons. Diffraction is described in terms of an ensemble of distinct, probability weighted paths for the scattered photons. The scattering associated with each path results from the quantized momentum exchange with the scattering lattice attributed to the exchange or reflection of virtual photons. The probability for virtual particle exchange/reflection is dependent upon the allowed momentum states of the lattice determined by a Fourier analysis of the lattice geometry. Any scattered photon will exhibit an apparent wavelength inversely proportional to its momentum. Simplified, particle-like descriptions are developed for Young"s double slit diffraction, Fraunhofer diffraction and Fresnel diffraction. This description directly accounts for the quantization of momentum transferred to the scattering lattice and the specific eigenvalues of the lattice based upon the constraints to virtual photon exchange set by the Uncertainty Principle, Δπi = h/ζi.

  19. Diffractive-optics-based beam combination of a phase-locked fiber laser array.

    PubMed

    Cheung, Eric C; Ho, James G; Goodno, Gregory D; Rice, Robert R; Rothenberg, Josh; Thielen, Peter; Weber, Mark; Wickham, Michael

    2008-02-15

    A diffractive optical element (DOE) is used as a beam combiner for an actively phase-locked array of fiber lasers. Use of a DOE eliminates the far-field sidelobes and the accompanying loss of beam quality typically observed in tiled coherent laser arrays. Using this technique, we demonstrated coherent combination of five fiber lasers with 91% efficiency and M2=1.04. Combination efficiency and phase locking is robust even with large amplitude and phase fluctuations on the input laser array elements. Calculations and power handling measurements suggest that this approach can scale to both high channel counts and high powers.

  20. Time-resolved measurements with streaked diffraction patterns from electrons generated in laser plasma wakefield

    NASA Astrophysics Data System (ADS)

    He, Zhaohan; Nees, John; Hou, Bixue; Krushelnick, Karl; Thomas, Alec; Beaurepaire, Benoît; Malka, Victor; Faure, Jérôme

    2013-10-01

    Femtosecond bunches of electrons with relativistic to ultra-relativistic energies can be robustly produced in laser plasma wakefield accelerators (LWFA). Scaling the electron energy down to sub-relativistic and MeV level using a millijoule laser system will make such electron source a promising candidate for ultrafast electron diffraction (UED) applications due to the intrinsic short bunch duration and perfect synchronization with the optical pump. Recent results of electron diffraction from a single crystal gold foil, using LWFA electrons driven by 8-mJ, 35-fs laser pulses at 500 Hz, will be presented. The accelerated electrons were collimated with a solenoid magnetic lens. By applying a small-angle tilt to the magnetic lens, the diffraction pattern can be streaked such that the temporal evolution is separated spatially on the detector screen after propagation. The observable time window and achievable temporal resolution are studied in pump-probe measurements of photo-induced heating on the gold foil.

  1. Spectral characteristics of multimode semiconductor lasers with a high-order surface diffraction grating

    SciTech Connect

    Zolotarev, V V; Leshko, A Yu; Pikhtin, N A; Lyutetskiy, A V; Slipchenko, S O; Bakhvalov, K V; Lubyanskiy, Ya V; Rastegaeva, M G; Tarasov, I S

    2014-10-31

    We have studied the spectral characteristics of multimode semiconductor lasers with high-order surface diffraction gratings based on asymmetric separate-confinement heterostructures grown by metalorganic vapour phase epitaxy (λ = 1070 nm). Experimental data demonstrate that, in the temperature range ±50 °C, the laser emission spectrum is ∼5 Å in width and contains a fine structure of longitudinal and transverse modes. A high-order (m = 15) surface diffraction grating is shown to ensure a temperature stability of the lasing spectrum dλ/dT = 0.9 Å K{sup -1} in this temperature range. From analysis of the fine structure of the lasing spectrum, we have evaluated the mode spacing and, thus, experimentally determined the effective length of the Bragg diffraction grating, which was ∼400 μm in our samples. (lasers)

  2. 70-Watt green laser with near diffraction-limited beam quality

    NASA Astrophysics Data System (ADS)

    Hu, Dan; Eisenberg, Eric; Madasamy, Pratheepan; Mead, Roy; Honea, Eric

    2009-02-01

    A 70-Watt green laser with M2<1.4 has been demonstrated. This green laser consists of an all-fiber-based IR pump laser at 1064 nm and a frequency-conversion module in a compact and flexible configuration. The IR laser produces up to 150 Watts in a polarized diffraction-limited output beam with high spectral brightness for frequency conversion. The IR laser is operating under QCW mode, e.g. 10 MHz with 3~5 ns pulse width or 700 MHz with 50 ps pulse width, to generate sufficient peak power for frequency doubling in the converter module. The IR laser and conversion module are connected via a 5-mm stainless-steel protected delivery fiber for optical beam delivery and an electrical cable harness for electrical power delivery and system control. Both the IR laser and converter module are run through embedded software that controls laser operations such as warm up and shut down. System overview and full characterization results will be presented. Such a high power green laser with near diffraction-limited output in a compact configuration will enable various scientific as well as industrial applications.

  3. CD, DVD, and Blu-Ray Disc Diffraction with a Laser Ray Box

    NASA Astrophysics Data System (ADS)

    DeWeerd, Alan J.

    2016-05-01

    A compact disc (CD) can be used as a diffraction grating, even though its track consists of a series of pits, not a continuous groove. Previous authors described how to measure the track spacing on a CD using an incident laser beam normal to the surface or one at an oblique angle. In both cases, the diffraction pattern was projected on a screen and distance measurements allowed the track spacing to be calculated. I propose an alternative method using a laser ray box, which is also applied to a DVD and a Blu-ray disc.

  4. Femtosecond diffraction dynamics of laser-induced periodic surface structures on fused silica

    SciTech Connect

    Hoehm, S.; Rosenfeld, A.; Krueger, J.; Bonse, J.

    2013-02-04

    The formation of laser-induced periodic surface structures (LIPSS) on fused silica upon irradiation with linearly polarized fs-laser pulses (50 fs pulse duration, 800 nm center wavelength) is studied experimentally using a transillumination femtosecond time-resolved (0.1 ps-1 ns) pump-probe diffraction approach. This allows to reveal the generation dynamics of near-wavelength-sized LIPSS showing a transient diffraction at specific spatial frequencies even before a corresponding permanent surface relief was observed. The results confirm that the ultrafast energy deposition to the materials surface plays a key role and triggers subsequent physical mechanisms such as carrier scattering into self-trapped excitons.

  5. Polarization-independent light-dispersing optical device consisting of two diffraction gratings and a waveplate.

    PubMed

    Amako, J; Fujii, E

    2014-06-10

    We report on a light-dispersing device consisting of two transmission gratings and a waveplate. The gratings separate two orthogonal polarization components of light incident at the Bragg angle. The waveplate, which is sandwiched between the gratings, functions as a polarization converter for oblique light incidence. With these optical parts suitably integrated, the resulting device efficiently diffracts unpolarized light with high spectral resolution. Using coupled-wave theories and Mueller matrix analysis, we constructed a device for a wavelength range of 680±50  nm with a 400 nm grating period. From the characterization of this optical device, we validated the proposed polarization-independent, light-dispersing concept.

  6. In situ laser heating and radial synchrotron X-ray diffraction ina diamond anvil cell

    SciTech Connect

    Kunz, Martin; Caldwell, Wendel A.; Miyagi, Lowell; Wenk,Hans-Rudolf

    2007-06-29

    We report a first combination of diamond anvil cell radialx-ray diffraction with in situ laser heating. The laser-heating setup ofALS beamline 12.2.2 was modified to allow one-sided heating of a samplein a diamond anvil cell with an 80 W yttrium lithium fluoride laser whileprobing the sample with radial x-ray diffraction. The diamond anvil cellis placed with its compressional axis vertical, and perpendicular to thebeam. The laser beam is focused onto the sample from the top while thesample is probed with hard x-rays through an x-ray transparentboron-epoxy gasket. The temperature response of preferred orientation of(Fe,Mg)O is probed as a test experiment. Recrystallization was observedabove 1500 K, accompanied by a decrease in stress.

  7. APPLICATION OF LASERS AND LASER-OPTICAL METHODS IN LIFE SCIENCES On the problem of the diffraction pattern visibility in laser diffractometry of red blood cells

    NASA Astrophysics Data System (ADS)

    Nikitin, Sergei Yu; Lugovtsov, Andrei E.; Priezzhev, A. V.

    2011-01-01

    We consider the problem of the visibility of the diffraction pattern that is observed in scattering laser radiation on the erythrocyte suspension in ectacytometer. The theoretical estimates show that 10% variation in the particle size reduces the diffraction pattern visibility by 1% only.

  8. Dual light field and polarization imaging using CMOS diffractive image sensors.

    PubMed

    Jayasuriya, Suren; Sivaramakrishnan, Sriram; Chuang, Ellen; Guruaribam, Debashree; Wang, Albert; Molnar, Alyosha

    2015-05-15

    In this Letter we present, to the best of our knowledge, the first integrated CMOS image sensor that can simultaneously perform light field and polarization imaging without the use of external filters or additional optical elements. Previous work has shown how photodetectors with two stacks of integrated metal gratings above them (called angle sensitive pixels) diffract light in a Talbot pattern to capture four-dimensional light fields. We show, in addition to diffractive imaging, that these gratings polarize incoming light and characterize the response of these sensors to polarization and incidence angle. Finally, we show two applications of polarization imaging: imaging stress-induced birefringence and identifying specular reflections in scenes to improve light field algorithms for these scenes.

  9. Dual light field and polarization imaging using CMOS diffractive image sensors.

    PubMed

    Jayasuriya, Suren; Sivaramakrishnan, Sriram; Chuang, Ellen; Guruaribam, Debashree; Wang, Albert; Molnar, Alyosha

    2015-05-15

    In this Letter we present, to the best of our knowledge, the first integrated CMOS image sensor that can simultaneously perform light field and polarization imaging without the use of external filters or additional optical elements. Previous work has shown how photodetectors with two stacks of integrated metal gratings above them (called angle sensitive pixels) diffract light in a Talbot pattern to capture four-dimensional light fields. We show, in addition to diffractive imaging, that these gratings polarize incoming light and characterize the response of these sensors to polarization and incidence angle. Finally, we show two applications of polarization imaging: imaging stress-induced birefringence and identifying specular reflections in scenes to improve light field algorithms for these scenes. PMID:26393758

  10. Investigation of correlation properties of light fields by Fresnel diffraction from a step

    NASA Astrophysics Data System (ADS)

    Hosseini, S. R.; Tavassoly, M. T.

    2013-12-01

    We introduce a new method, based on Fresnel diffraction of light from a step, for the study of correlation properties (temporal and spatial) of optical fields. The method renders to measure wavelength, coherence length, and coherence width by recording the visibility of the diffraction fringes versus optical path difference and spacing of the interfering beams. In addition, the method permits to specify the spectral line shape, particularly, of lights with short coherence lengths and the spatial coherence behavior of the lights with short coherence widths. Since, in the introduced method the optical path difference can be varied by changing the light incident angle, practically, in an interval of 90º, a large volume of data is acquired which leads to reliable and accurate study of the subject. The method can be applied easily using modest equipment. We have applied the method to the study of correlation properties of the lights emitted by LED, incandescent bulb, and Hg lamp.

  11. Laser Ablated Carbon Nanodots for Light Emission.

    PubMed

    Reyes, Delfino; Camacho, Marco; Camacho, Miguel; Mayorga, Miguel; Weathers, Duncan; Salamo, Greg; Wang, Zhiming; Neogi, Arup

    2016-12-01

    The synthesis of fluorescent carbon dots-like nanostructures (CNDs) obtained through the laser ablation of a carbon solid target in liquid environment is reported. The ablation process was induced in acetone with laser pulses of 1064, 532, and 355 nm under different irradiation times. Close-spherical amorphous CNDs with sizes between 5 and 20 nm, whose abundance strongly depends on the ablation parameters were investigated using electron microscopy and was confirmed using absorption and emission spectroscopies. The π- π* electronic transition at 3.76 eV dominates the absorption for all the CNDs species synthesized under different irradiation conditions. The light emission is most efficient due to excitation at 3.54 eV with the photoluminescence intensity centered at 3.23 eV. The light emission from the CNDs is most efficient due to ablation at 355 nm. The emission wavelength of the CNDs can be tuned from the near-UV to the green wavelength region by controlling the ablation time and modifying the ablation and excitation laser wavelength.

  12. Laser Ablated Carbon Nanodots for Light Emission

    NASA Astrophysics Data System (ADS)

    Reyes, Delfino; Camacho, Marco; Camacho, Miguel; Mayorga, Miguel; Weathers, Duncan; Salamo, Greg; Wang, Zhiming; Neogi, Arup

    2016-09-01

    The synthesis of fluorescent carbon dots-like nanostructures (CNDs) obtained through the laser ablation of a carbon solid target in liquid environment is reported. The ablation process was induced in acetone with laser pulses of 1064, 532, and 355 nm under different irradiation times. Close-spherical amorphous CNDs with sizes between 5 and 20 nm, whose abundance strongly depends on the ablation parameters were investigated using electron microscopy and was confirmed using absorption and emission spectroscopies. The π- π* electronic transition at 3.76 eV dominates the absorption for all the CNDs species synthesized under different irradiation conditions. The light emission is most efficient due to excitation at 3.54 eV with the photoluminescence intensity centered at 3.23 eV. The light emission from the CNDs is most efficient due to ablation at 355 nm. The emission wavelength of the CNDs can be tuned from the near-UV to the green wavelength region by controlling the ablation time and modifying the ablation and excitation laser wavelength.

  13. Laser Ablated Carbon Nanodots for Light Emission.

    PubMed

    Reyes, Delfino; Camacho, Marco; Camacho, Miguel; Mayorga, Miguel; Weathers, Duncan; Salamo, Greg; Wang, Zhiming; Neogi, Arup

    2016-12-01

    The synthesis of fluorescent carbon dots-like nanostructures (CNDs) obtained through the laser ablation of a carbon solid target in liquid environment is reported. The ablation process was induced in acetone with laser pulses of 1064, 532, and 355 nm under different irradiation times. Close-spherical amorphous CNDs with sizes between 5 and 20 nm, whose abundance strongly depends on the ablation parameters were investigated using electron microscopy and was confirmed using absorption and emission spectroscopies. The π- π* electronic transition at 3.76 eV dominates the absorption for all the CNDs species synthesized under different irradiation conditions. The light emission is most efficient due to excitation at 3.54 eV with the photoluminescence intensity centered at 3.23 eV. The light emission from the CNDs is most efficient due to ablation at 355 nm. The emission wavelength of the CNDs can be tuned from the near-UV to the green wavelength region by controlling the ablation time and modifying the ablation and excitation laser wavelength. PMID:27659953

  14. Study of the spatial resolution of laser thermochemical technology for recording diffraction microstructures

    SciTech Connect

    Veiko, V P; Korol'kov, V I; Poleshchuk, A G; Sametov, A R; Shakhno, E A; Yarchuk, M V

    2011-07-31

    The thermochemical method for recording data, which is based on local laser oxidation of a thin metal film with subsequent etching of the unirradiated region, is an alternative to laser photolithography and direct laser removal of the film material. This recording technology is characterised by the absence of thermal and hydrodynamic image distortions, as in the case of laser ablation, and the number of necessary technological operations is much smaller as compared with the photomask preparation in classical photolithography. The main field of application of the thermochemical technology is the fabrication of diffraction optical elements (DOEs), which are widely used in printers, bar-code readers, CD and DVD laser players, etc. The purpose of this study is to increase the resolution of thermochemical data recording on thin chromium films. (interaction of laser radiation with matter)

  15. Lasers.

    ERIC Educational Resources Information Center

    Schewe, Phillip F.

    1981-01-01

    Examines the nature of laser light. Topics include: (1) production and characteristics of laser light; (2) nine types of lasers; (3) five laser techniques including holography; (4) laser spectroscopy; and (5) laser fusion and other applications. (SK)

  16. Threshold Characteristics of Slow-Light Photonic Crystal Lasers.

    PubMed

    Xue, Weiqi; Yu, Yi; Ottaviano, Luisa; Chen, Yaohui; Semenova, Elizaveta; Yvind, Kresten; Mork, Jesper

    2016-02-12

    The threshold properties of photonic crystal quantum dot lasers operating in the slow-light regime are investigated experimentally and theoretically. Measurements show that, in contrast to conventional lasers, the threshold gain attains a minimum value for a specific cavity length. The experimental results are explained by an analytical theory for the laser threshold that takes into account the effects of slow light and random disorder due to unavoidable fabrication imperfections. Longer lasers are found to operate deeper into the slow-light region, leading to a trade-off between slow-light induced reduction of the mirror loss and slow-light enhancement of disorder-induced losses. PMID:26918991

  17. Threshold Characteristics of Slow-Light Photonic Crystal Lasers

    NASA Astrophysics Data System (ADS)

    Xue, Weiqi; Yu, Yi; Ottaviano, Luisa; Chen, Yaohui; Semenova, Elizaveta; Yvind, Kresten; Mork, Jesper

    2016-02-01

    The threshold properties of photonic crystal quantum dot lasers operating in the slow-light regime are investigated experimentally and theoretically. Measurements show that, in contrast to conventional lasers, the threshold gain attains a minimum value for a specific cavity length. The experimental results are explained by an analytical theory for the laser threshold that takes into account the effects of slow light and random disorder due to unavoidable fabrication imperfections. Longer lasers are found to operate deeper into the slow-light region, leading to a trade-off between slow-light induced reduction of the mirror loss and slow-light enhancement of disorder-induced losses.

  18. Evaluation of Laser Based Alignment Algorithms Under Additive Random and Diffraction Noise

    SciTech Connect

    McClay, W A; Awwal, A; Wilhelmsen, K; Ferguson, W; McGee, M; Miller, M

    2004-09-30

    The purpose of the automatic alignment algorithm at the National Ignition Facility (NIF) is to determine the position of a laser beam based on the position of beam features from video images. The position information obtained is used to command motors and attenuators to adjust the beam lines to the desired position, which facilitates the alignment of all 192 beams. One of the goals of the algorithm development effort is to ascertain the performance, reliability, and uncertainty of the position measurement. This paper describes a method of evaluating the performance of algorithms using Monte Carlo simulation. In particular we show the application of this technique to the LM1{_}LM3 algorithm, which determines the position of a series of two beam light sources. The performance of the algorithm was evaluated for an ensemble of over 900 simulated images with varying image intensities and noise counts, as well as varying diffraction noise amplitude and frequency. The performance of the algorithm on the image data set had a tolerance well beneath the 0.5-pixel system requirement.

  19. Pulsed laser light sheet flow visualization

    NASA Astrophysics Data System (ADS)

    Soreide, D. C.; Douglas, G. D.; Brandt, W. P.

    A pulsed ruby laser was used as light source for a set of flow visualization tests involving two test situations. In both cases, the conducted investigation was concerned with the location of the tip vortex of the rotor-blade of a helicopter, giving particular attention to the position relative to the following blade. The optical system employed is considered along with the electronics system, the setup equipment, and the helicopter test. Vortex field maps are provided for the case in which the helicopter rotor vortex field phase angle equals 0 degrees and for the case in which this angle equals 90 degrees.

  20. Software for portable laser light show system

    NASA Astrophysics Data System (ADS)

    Buruchin, Dmitrey J.; Leonov, Alexander F.

    1995-04-01

    Portable laser light show system LS-3500-10M is connected to the parallel port of IBM PC/AT compatible computer. Computer performs output of digital control data describing images. Specially designed control device is used to convert digital data coming from parallel port to the analog signal driving scanner. Capabilities of even cost nothing 286 computer are quite enough for laser graphics control. Technology of scanning used in laser graphics system LS-3500-10M essentially differs from widely spread systems based on galvanometers with mobile core or with mobile magnet. Such devices are based on the same principle of work as electrically driven servo-mechanism. As scanner we use elastic system with hydraulic dampen oscillations and opened loop. For most of applications of laser graphics such system provides satisfactory precision and speed of scanning. LS-3500-10M software gives user ability to create on PC and play his own laser graphics demonstrations. It is possible to render recognizable text and pictures using different styles, 3D and abstract animation. All types of demonstrations can be mixed in slide-show. Time synchronization is supported. Software has the following features: (1) Different types of text output. Built-in text editor for typing and editing of textural information. Different fonts can be used to display text. User can create his own fonts using specially developed font editor. (2) Editor of 3D animation with library of predefined shapes. (3) Abstract animation provided by software routines. (4) Support of different graphics files formats (PCX or DXF). Original algorithm of raster image tracing was implemented. (5) Built-in slide-show editor.

  1. Diffractive optical devices produced by light-assisted trapping of nanoparticles.

    PubMed

    Muñoz-Martínez, J F; Jubera, M; Matarrubia, J; García-Cabañes, A; Agulló-López, F; Carrascosa, M

    2016-01-15

    One- and two-dimensional diffractive optical devices have been fabricated by light-assisted trapping and patterning of nanoparticles. The method is based on the dielectrophoretic forces appearing in the vicinity of a photovoltaic crystal, such as Fe:LiNbO3, during or after illumination. By illumination with the appropriate light distribution, the nanoparticles are organized along patterns designed at will. One- and two-dimensional diffractive components have been achieved on X- and Z-cut Fe:LiNbO3 crystals, with their polar axes parallel and perpendicular to the crystal surface, respectively. Diffraction gratings with periods down to around a few micrometers have been produced using metal (Al, Ag) nanoparticles with radii in the range of 70-100 nm. Moreover, several 2D devices, such as Fresnel zone plates, have been also produced showing the potential of the method. The diffractive particle patterns remain stable when light is removed. A method to transfer the diffractive patterns to other nonphotovoltaic substrates, such as silica glass, has been also reported.

  2. Breaking the diffraction limit of light-sheet fluorescence microscopy by RESOLFT.

    PubMed

    Hoyer, Patrick; de Medeiros, Gustavo; Balázs, Bálint; Norlin, Nils; Besir, Christina; Hanne, Janina; Kräusslich, Hans-Georg; Engelhardt, Johann; Sahl, Steffen J; Hell, Stefan W; Hufnagel, Lars

    2016-03-29

    We present a plane-scanning RESOLFT [reversible saturable/switchable optical (fluorescence) transitions] light-sheet (LS) nanoscope, which fundamentally overcomes the diffraction barrier in the axial direction via confinement of the fluorescent molecular state to a sheet of subdiffraction thickness around the focal plane. To this end, reversibly switchable fluorophores located right above and below the focal plane are transferred to a nonfluorescent state at each scanning step. LS-RESOLFT nanoscopy offers wide-field 3D imaging of living biological specimens with low light dose and axial resolution far beyond the diffraction barrier. We demonstrate optical sections that are thinner by 5-12-fold compared with their conventional diffraction-limited LS analogs. PMID:26984498

  3. Breaking the diffraction limit of light-sheet fluorescence microscopy by RESOLFT

    NASA Astrophysics Data System (ADS)

    Hoyer, Patrick; de Medeiros, Gustavo; Balázs, Bálint; Norlin, Nils; Besir, Christina; Hanne, Janina; Kräusslich, Hans-Georg; Engelhardt, Johann; Sahl, Steffen J.; Hell, Stefan W.; Hufnagel, Lars

    2016-03-01

    We present a plane-scanning RESOLFT [reversible saturable/switchable optical (fluorescence) transitions] light-sheet (LS) nanoscope, which fundamentally overcomes the diffraction barrier in the axial direction via confinement of the fluorescent molecular state to a sheet of subdiffraction thickness around the focal plane. To this end, reversibly switchable fluorophores located right above and below the focal plane are transferred to a nonfluorescent state at each scanning step. LS-RESOLFT nanoscopy offers wide-field 3D imaging of living biological specimens with low light dose and axial resolution far beyond the diffraction barrier. We demonstrate optical sections that are thinner by 5-12-fold compared with their conventional diffraction-limited LS analogs.

  4. Polarization sensitivity of light diffraction for periodic array of anisotropic gold nanoparticles

    SciTech Connect

    Tsai, Ming-shan Liu, Tung-kai; Tsen, Chun-yu; Ting, Chen-ching

    2015-06-15

    This article aims to analyze the first order diffraction intensity of the incident polarized light which is diffracted by the gold nanoparticles array in terms of the surface plasmon effect. The inspected gold nanoparticles array films are built in grating pattern with stripe thickness of 4 μm and diameters of gold nanoparticles ca. 10–56 nm, which are formed by annealing at temperatures of 400, 450, 500, and 550 °C, respectively. The probing light is linearly polarized with wavelengths of 450–800 nm and counterclockwise turns its polarization direction from 0° to 90° during measurements. The results show that the diffraction intensity depends on the anisotropic configuration samples which gold nanoparticles are orientated by analyzing the scanning electron microscope images. It results that the localized surface plasmon effect induced by incident field depends on orientation and causes the sample polarization-sensitive.

  5. Breaking the diffraction limit of light-sheet fluorescence microscopy by RESOLFT

    PubMed Central

    Hoyer, Patrick; de Medeiros, Gustavo; Balázs, Bálint; Norlin, Nils; Besir, Christina; Hanne, Janina; Kräusslich, Hans-Georg; Engelhardt, Johann; Sahl, Steffen J.; Hell, Stefan W.; Hufnagel, Lars

    2016-01-01

    We present a plane-scanning RESOLFT [reversible saturable/switchable optical (fluorescence) transitions] light-sheet (LS) nanoscope, which fundamentally overcomes the diffraction barrier in the axial direction via confinement of the fluorescent molecular state to a sheet of subdiffraction thickness around the focal plane. To this end, reversibly switchable fluorophores located right above and below the focal plane are transferred to a nonfluorescent state at each scanning step. LS-RESOLFT nanoscopy offers wide-field 3D imaging of living biological specimens with low light dose and axial resolution far beyond the diffraction barrier. We demonstrate optical sections that are thinner by 5–12-fold compared with their conventional diffraction-limited LS analogs. PMID:26984498

  6. Laser-diffraction-assisted ordering effects in nano-quasipercolated silver thin films.

    NASA Astrophysics Data System (ADS)

    Haro-Poniatowski, E.; Alonso-Huitron, J. C.; Acosta-Zepeda, C.; Acosta-Garcia, M. C.; Batina, N.

    2009-03-01

    Nanostructured silver thin films in a quasipercolated state are used as the starting morphology for inducing changes in shape and ordering effects by pulsed laser irradiation with a Nd:YAG laser (355 nm) [1,2]. The complex nanostructures are transformed into nanospheres which in turn are ordered in regular patterns when irradiated through a diffractive element such as a slit or a pinhole. The samples are deposited onto TEM grids by the pulsed laser deposition technique. These transformations are subsequently characterized by transmission electron microscopy and by atomic force microscopy. The observed effects are explained using Fresnel diffraction theory. Excellent agreement with the experimental results are obtained. [1] E. Haro-Poniatowski et al. Appl. Phys. Lett. 87, 143103, 2005 [2] E. Haro-Poniatowski et al. Radiation Effects & Defects in Solids 162, 491-499 (2007)

  7. Green laser light activates the inner ear

    NASA Astrophysics Data System (ADS)

    Wenzel, Gentiana I.; Balster, Sven; Zhang, Kaiyin; Lim, Hubert H.; Reich, Uta; Massow, Ole; Lubatschowski, Holger; Ertmer, Wolfgang; Lenarz, Thomas; Reuter, Guenter

    2009-07-01

    The hearing performance with conventional hearing aids and cochlear implants is dramatically reduced in noisy environments and for sounds more complex than speech (e. g. music), partially due to the lack of localized sensorineural activation across different frequency regions with these devices. Laser light can be focused in a controlled manner and may provide more localized activation of the inner ear, the cochlea. We sought to assess whether visible light with parameters that could induce an optoacoustic effect (532 nm, 10-ns pulses) would activate the cochlea. Auditory brainstem responses (ABRs) were recorded preoperatively in anesthetized guinea pigs to confirm normal hearing. After opening the bulla, a 50-μm core-diameter optical fiber was positioned in the round window niche and directed toward the basilar membrane. Optically induced ABRs (OABRs), similar in shape to those of acoustic stimulation, were elicited with single pulses. The OABR peaks increased with energy level (0.6 to 23 μJ/pulse) and remained consistent even after 30 minutes of continuous stimulation at 13 μJ, indicating minimal or no stimulation-induced damage within the cochlea. Our findings demonstrate that visible light can effectively and reliably activate the cochlea without any apparent damage. Further studies are in progress to investigate the frequency-specific nature and mechanism of green light cochlear activation.

  8. Adaptive Fraunhofer diffraction particle sizing instrument using a spatial light modulator.

    PubMed

    Hirleman, E D; Dellenback, P A

    1989-11-15

    Integration of a magnetooptic spatial light modulator into a Fraunhofer diffraction particle sizing instrument is proposed and demonstrated theoretically and experimentally. The concept gives the instrument the ability to reconfigure a detector array on-line and thereby adapt to the measurement context.

  9. Geometrical Reasoning in Wave Situations: The Case of Light Diffraction and Coherent Illumination Optical Imaging

    ERIC Educational Resources Information Center

    Maurines, Laurence

    2010-01-01

    This particular study is part of a research programme on the difficulties encountered by students when learning about wave phenomena in a three-dimensional medium in the absence or presence of obstacles. It focuses on how students reason in situations in which wave optics need to be used: diffraction of light by an aperture, imaging in the…

  10. Parallelized genetic optimization of spatial light modulator addressing for diffractive applications.

    PubMed

    Haist, Tobias; Lingel, Christian; Adler, Rodolfo; Osten, Wolfgang

    2014-03-01

    We describe a new technique for optimizing the addressing of spatial light modulators in dynamic holographic applications. The method utilizes 200 times parallelization using imaging of subholograms in combination with genetic optimization. Compared to a fixed linear addressing curve for all different gratings, the diffraction efficiency can be improved by up to 25% for a Holoeye Pluto LCoS modulator. PMID:24663371

  11. Adaptive Fraunhofer diffraction particle sizing instrument using a spatial light modulator.

    PubMed

    Hirleman, E D; Dellenback, P A

    1989-11-15

    Integration of a magnetooptic spatial light modulator into a Fraunhofer diffraction particle sizing instrument is proposed and demonstrated theoretically and experimentally. The concept gives the instrument the ability to reconfigure a detector array on-line and thereby adapt to the measurement context. PMID:20555963

  12. Microfluidic sorting of protein nanocrystals by size for X-ray free-electron laser diffraction

    SciTech Connect

    Abdallah, Bahige G.; Zatsepin, Nadia A.; Roy-Chowdhury, Shatabdi; Coe, Jesse; Conrad, Chelsie E.; Dörner, Katerina; Sierra, Raymond G.; Stevenson, Hilary P.; Camacho-Alanis, Fernanda; Grant, Thomas D.; Nelson, Garrett; James, Daniel; Calero, Guillermo; Wachter, Rebekka M.; Spence, John C. H.; Weierstall, Uwe; Fromme, Petra; Ros, Alexandra

    2015-08-19

    We report that the advent and application of the X-ray free-electron laser (XFEL) has uncovered the structures of proteins that could not previously be solved using traditional crystallography. While this new technology is powerful, optimization of the process is still needed to improve data quality and analysis efficiency. One area is sample heterogeneity, where variations in crystal size (among other factors) lead to the requirement of large data sets (and thus 10–100 mg of protein) for determining accurate structure factors. To decrease sample dispersity, we developed a high-throughput microfluidic sorter operating on the principle of dielectrophoresis, whereby polydisperse particles can be transported into various fluid streams for size fractionation. Using this microsorter, we isolated several milliliters of photosystem I nanocrystal fractions ranging from 200 to 600 nm in size as characterized by dynamic light scattering, nanoparticle tracking, and electron microscopy. Sorted nanocrystals were delivered in a liquid jet via the gas dynamic virtual nozzle into the path of the XFEL at the Linac Coherent Light Source. We obtained diffraction to ~4 Å resolution, indicating that the small crystals were not damaged by the sorting process. We also observed the shape transforms of photosystem I nanocrystals, demonstrating that our device can optimize data collection for the shape transform-based phasing method. Using simulations, we show that narrow crystal size distributions can significantly improve merged data quality in serial crystallography. From this proof-of-concept work, we expect that the automated size-sorting of protein crystals will become an important step for sample production by reducing the amount of protein needed for a high quality final structure and the development of novel phasing methods that exploit inter-Bragg reflection intensities or use variations in beam intensity for radiation damage-induced phasing. Ultimately, this method will also

  13. Microfluidic sorting of protein nanocrystals by size for X-ray free-electron laser diffraction

    DOE PAGESBeta

    Abdallah, Bahige G.; Zatsepin, Nadia A.; Roy-Chowdhury, Shatabdi; Coe, Jesse; Conrad, Chelsie E.; Dörner, Katerina; Sierra, Raymond G.; Stevenson, Hilary P.; Camacho-Alanis, Fernanda; Grant, Thomas D.; et al

    2015-08-19

    We report that the advent and application of the X-ray free-electron laser (XFEL) has uncovered the structures of proteins that could not previously be solved using traditional crystallography. While this new technology is powerful, optimization of the process is still needed to improve data quality and analysis efficiency. One area is sample heterogeneity, where variations in crystal size (among other factors) lead to the requirement of large data sets (and thus 10–100 mg of protein) for determining accurate structure factors. To decrease sample dispersity, we developed a high-throughput microfluidic sorter operating on the principle of dielectrophoresis, whereby polydisperse particles canmore » be transported into various fluid streams for size fractionation. Using this microsorter, we isolated several milliliters of photosystem I nanocrystal fractions ranging from 200 to 600 nm in size as characterized by dynamic light scattering, nanoparticle tracking, and electron microscopy. Sorted nanocrystals were delivered in a liquid jet via the gas dynamic virtual nozzle into the path of the XFEL at the Linac Coherent Light Source. We obtained diffraction to ~4 Å resolution, indicating that the small crystals were not damaged by the sorting process. We also observed the shape transforms of photosystem I nanocrystals, demonstrating that our device can optimize data collection for the shape transform-based phasing method. Using simulations, we show that narrow crystal size distributions can significantly improve merged data quality in serial crystallography. From this proof-of-concept work, we expect that the automated size-sorting of protein crystals will become an important step for sample production by reducing the amount of protein needed for a high quality final structure and the development of novel phasing methods that exploit inter-Bragg reflection intensities or use variations in beam intensity for radiation damage-induced phasing. Ultimately, this method

  14. Microfluidic sorting of protein nanocrystals by size for X-ray free-electron laser diffraction

    PubMed Central

    Abdallah, Bahige G.; Zatsepin, Nadia A.; Roy-Chowdhury, Shatabdi; Coe, Jesse; Conrad, Chelsie E.; Dörner, Katerina; Sierra, Raymond G.; Stevenson, Hilary P.; Camacho-Alanis, Fernanda; Grant, Thomas D.; Nelson, Garrett; James, Daniel; Calero, Guillermo; Wachter, Rebekka M.; Spence, John C. H.; Weierstall, Uwe; Fromme, Petra; Ros, Alexandra

    2015-01-01

    The advent and application of the X-ray free-electron laser (XFEL) has uncovered the structures of proteins that could not previously be solved using traditional crystallography. While this new technology is powerful, optimization of the process is still needed to improve data quality and analysis efficiency. One area is sample heterogeneity, where variations in crystal size (among other factors) lead to the requirement of large data sets (and thus 10–100 mg of protein) for determining accurate structure factors. To decrease sample dispersity, we developed a high-throughput microfluidic sorter operating on the principle of dielectrophoresis, whereby polydisperse particles can be transported into various fluid streams for size fractionation. Using this microsorter, we isolated several milliliters of photosystem I nanocrystal fractions ranging from 200 to 600 nm in size as characterized by dynamic light scattering, nanoparticle tracking, and electron microscopy. Sorted nanocrystals were delivered in a liquid jet via the gas dynamic virtual nozzle into the path of the XFEL at the Linac Coherent Light Source. We obtained diffraction to ∼4 Å resolution, indicating that the small crystals were not damaged by the sorting process. We also observed the shape transforms of photosystem I nanocrystals, demonstrating that our device can optimize data collection for the shape transform-based phasing method. Using simulations, we show that narrow crystal size distributions can significantly improve merged data quality in serial crystallography. From this proof-of-concept work, we expect that the automated size-sorting of protein crystals will become an important step for sample production by reducing the amount of protein needed for a high quality final structure and the development of novel phasing methods that exploit inter-Bragg reflection intensities or use variations in beam intensity for radiation damage-induced phasing. This method will also permit an analysis

  15. Fraunhofer diffraction of Laguerre-Gaussian laser beam by helical axicon

    NASA Astrophysics Data System (ADS)

    Topuzoski, S.

    2014-11-01

    In this article we present a theoretical study for Fraunhofer diffraction of a Laguerre-Gaussian laser beam with “0” radial mode number and “l” azimuthal mode number (LG0l) by helical axicon. Analytical expressions describing the diffracted wave field amplitude and intensity distributions in the back focal plane of a convergent lens are derived in a form of product of a Gauss-doughnut function and a sum of hypergeometric Kummer functions. Also, the diffracted LG beam by axicon only, as well as by spiral phase plate only, and the diffracted Gaussian beam by helical axicon, are described mathematically in the back focal plane of a convergent lens. Different possibilities for obtaining output vortex beam with reduced or increased topological charge compared to that of the incident beam, or for obtaining chargeless beam are analyzed.

  16. Small bore ceramic laser tube inspection light table

    DOEpatents

    Updike, Earl O.

    1990-01-01

    Apparatus for inspecting small bore ceramic laser tubes, which includes a support base with one or more support rollers. A fluorescent light tube is inserted within the laser tube and the laser tube is supported by the support rollers so that a gap is maintained between the laser tube and the fluorescent tube to enable rotation of the laser tube. In operation, the ceramic tube is illuminated from the inside by the fluorescent tube to facilitate visual inspection. Centering the tube around the axial light of the fluorescent tube provides information about straightness and wall thickness of the laser tube itself.

  17. 7 Å resolution in protein two-dimensional-crystal X-ray diffraction at Linac Coherent Light Source

    PubMed Central

    Pedrini, Bill; Tsai, Ching-Ju; Capitani, Guido; Padeste, Celestino; Hunter, Mark S.; Zatsepin, Nadia A.; Barty, Anton; Benner, W. Henry; Boutet, Sébastien; Feld, Geoffrey K.; Hau-Riege, Stefan P.; Kirian, Richard A.; Kupitz, Christopher; Messerschmitt, Marc; Ogren, John I.; Pardini, Tommaso; Segelke, Brent; Williams, Garth J.; Spence, John C. H.; Abela, Rafael; Coleman, Matthew; Evans, James E.; Schertler, Gebhard F. X.; Frank, Matthias; Li, Xiao-Dan

    2014-01-01

    Membrane proteins arranged as two-dimensional crystals in the lipid environment provide close-to-physiological structural information, which is essential for understanding the molecular mechanisms of protein function. Previously, X-ray diffraction from individual two-dimensional crystals did not represent a suitable investigational tool because of radiation damage. The recent availability of ultrashort pulses from X-ray free-electron lasers (XFELs) has now provided a means to outrun the damage. Here, we report on measurements performed at the Linac Coherent Light Source XFEL on bacteriorhodopsin two-dimensional crystals mounted on a solid support and kept at room temperature. By merging data from about a dozen single crystal diffraction images, we unambiguously identified the diffraction peaks to a resolution of 7 Å, thus improving the observable resolution with respect to that achievable from a single pattern alone. This indicates that a larger dataset will allow for reliable quantification of peak intensities, and in turn a corresponding increase in the resolution. The presented results pave the way for further XFEL studies on two-dimensional crystals, which may include pump–probe experiments at subpicosecond time resolution. PMID:24914166

  18. 7 Å resolution in protein two-dimensional-crystal X-ray diffraction at Linac Coherent Light Source.

    PubMed

    Pedrini, Bill; Tsai, Ching-Ju; Capitani, Guido; Padeste, Celestino; Hunter, Mark S; Zatsepin, Nadia A; Barty, Anton; Benner, W Henry; Boutet, Sébastien; Feld, Geoffrey K; Hau-Riege, Stefan P; Kirian, Richard A; Kupitz, Christopher; Messerschmitt, Marc; Ogren, John I; Pardini, Tommaso; Segelke, Brent; Williams, Garth J; Spence, John C H; Abela, Rafael; Coleman, Matthew; Evans, James E; Schertler, Gebhard F X; Frank, Matthias; Li, Xiao-Dan

    2014-07-17

    Membrane proteins arranged as two-dimensional crystals in the lipid environment provide close-to-physiological structural information, which is essential for understanding the molecular mechanisms of protein function. Previously, X-ray diffraction from individual two-dimensional crystals did not represent a suitable investigational tool because of radiation damage. The recent availability of ultrashort pulses from X-ray free-electron lasers (XFELs) has now provided a means to outrun the damage. Here, we report on measurements performed at the Linac Coherent Light Source XFEL on bacteriorhodopsin two-dimensional crystals mounted on a solid support and kept at room temperature. By merging data from about a dozen single crystal diffraction images, we unambiguously identified the diffraction peaks to a resolution of 7 Å, thus improving the observable resolution with respect to that achievable from a single pattern alone. This indicates that a larger dataset will allow for reliable quantification of peak intensities, and in turn a corresponding increase in the resolution. The presented results pave the way for further XFEL studies on two-dimensional crystals, which may include pump-probe experiments at subpicosecond time resolution.

  19. 7 Å resolution in protein two-dimensional-crystal X-ray diffraction at Linac Coherent Light Source.

    PubMed

    Pedrini, Bill; Tsai, Ching-Ju; Capitani, Guido; Padeste, Celestino; Hunter, Mark S; Zatsepin, Nadia A; Barty, Anton; Benner, W Henry; Boutet, Sébastien; Feld, Geoffrey K; Hau-Riege, Stefan P; Kirian, Richard A; Kupitz, Christopher; Messerschmitt, Marc; Ogren, John I; Pardini, Tommaso; Segelke, Brent; Williams, Garth J; Spence, John C H; Abela, Rafael; Coleman, Matthew; Evans, James E; Schertler, Gebhard F X; Frank, Matthias; Li, Xiao-Dan

    2014-07-17

    Membrane proteins arranged as two-dimensional crystals in the lipid environment provide close-to-physiological structural information, which is essential for understanding the molecular mechanisms of protein function. Previously, X-ray diffraction from individual two-dimensional crystals did not represent a suitable investigational tool because of radiation damage. The recent availability of ultrashort pulses from X-ray free-electron lasers (XFELs) has now provided a means to outrun the damage. Here, we report on measurements performed at the Linac Coherent Light Source XFEL on bacteriorhodopsin two-dimensional crystals mounted on a solid support and kept at room temperature. By merging data from about a dozen single crystal diffraction images, we unambiguously identified the diffraction peaks to a resolution of 7 Å, thus improving the observable resolution with respect to that achievable from a single pattern alone. This indicates that a larger dataset will allow for reliable quantification of peak intensities, and in turn a corresponding increase in the resolution. The presented results pave the way for further XFEL studies on two-dimensional crystals, which may include pump-probe experiments at subpicosecond time resolution. PMID:24914166

  20. Adaptability of laser diffraction measurement technique in soil physics methodology

    NASA Astrophysics Data System (ADS)

    Barna, Gyöngyi; Szabó, József; Rajkai, Kálmán; Bakacsi, Zsófia; Koós, Sándor; László, Péter; Hauk, Gabriella; Makó, András

    2016-04-01

    There are intentions all around the world to harmonize soils' particle size distribution (PSD) data by the laser diffractometer measurements (LDM) to that of the sedimentation techniques (pipette or hydrometer methods). Unfortunately, up to the applied methodology (e. g. type of pre-treatments, kind of dispersant etc.), PSDs of the sedimentation methods (due to different standards) are dissimilar and could be hardly harmonized with each other, as well. A need was arisen therefore to build up a database, containing PSD values measured by the pipette method according to the Hungarian standard (MSZ-08. 0205: 1978) and the LDM according to a widespread and widely used procedure. In our current publication the first results of statistical analysis of the new and growing PSD database are presented: 204 soil samples measured with pipette method and LDM (Malvern Mastersizer 2000, HydroG dispersion unit) were compared. Applying usual size limits at the LDM, clay fraction was highly under- and silt fraction was overestimated compared to the pipette method. Subsequently soil texture classes determined from the LDM measurements significantly differ from results of the pipette method. According to previous surveys and relating to each other the two dataset to optimizing, the clay/silt boundary at LDM was changed. Comparing the results of PSDs by pipette method to that of the LDM, in case of clay and silt fractions the modified size limits gave higher similarities. Extension of upper size limit of clay fraction from 0.002 to 0.0066 mm, and so change the lower size limit of silt fractions causes more easy comparability of pipette method and LDM. Higher correlations were found between clay content and water vapor adsorption, specific surface area in case of modified limit, as well. Texture classes were also found less dissimilar. The difference between the results of the two kind of PSD measurement methods could be further reduced knowing other routinely analyzed soil parameters

  1. Teaching Diffraction of Light and Electrons: Classroom Analogies to Classic Experiments

    NASA Astrophysics Data System (ADS)

    Velentzas, Athanasios

    2014-11-01

    Diffraction and interference are phenomena that demonstrate the wave nature of light and of particles. Experiments relating to the diffraction/interference of light can easily be carried out in an educational lab, but it may be impossible to perform experiments involving electrons because of the lack of specialized equipment needed for such experiments. It would, however, be possible for students to analyze data from scientific experiments by analogy to experiments they themselves had performed. Based on this rationale, this paper describes two pairs of experiments that may be of interest to teachers aiming to teach the wave nature of light and of particles to upper secondary school (or to college) students. Specifically, students are asked to (i) carry out a double-slit experiment by using monochromatic light, thus repeating in a way the historical experiment of Young,1 and then analyze real data from Jönsson's2-3 scientific double-slit experiment with electrons, and (ii) perform an experiment involving diffraction of monochromatic light using a compact disc (CD) as a reflection grating, and then by analogy analyze data from the experiment of Davisson and Germer.4 The proposed real experiments are not original, and different versions of them have been wi dely described in the literature.5,6 The educational value of the present work lies in the use of the analogy between experiments carried out in the school lab and experiments performed in the scientific lab.

  2. Light trapping by backside diffraction gratings in silicon solar cells revisited.

    PubMed

    Wellenzohn, Markus; Hainberger, Rainer

    2012-01-01

    This numerical study investigates the influence of rectangular backside diffraction gratings on the efficiency of silicon solar cells. Backside gratings are used to diffract incident light to large propagation angles beyond the angle of total internal reflection, which can significantly increase the interaction length of long wavelength photons inside the silicon layer and thus enhance the efficiency. We investigate the influence of the silicon thickness on the optimum grating period and modulation depth by a simulation method which combines a 2D ray tracing algorithm with rigorous coupled wave analysis (RCWA) for calculating the grating diffraction efficiencies. The optimization was performed for gratings with period lengths ranging from 0.25 µm to 1.5 µm and modulation depths ranging from 25 nm to 400 nm under the assumption of normal light incidence. This study shows that the achievable efficiency improvement of silicon solar cells by means of backside diffraction gratings strongly depends on the proper choice of the grating parameters for a given silicon thickness. The relationship between the optimized grating parameters resulting in maximum photocurrent densities and the silicon thickness is determined. Moreover, the thicknesses of silicon solar cells with and without optimized backside diffraction gratings providing the same photocurrent densities are compared.

  3. Note: Laser beam scanning using a ferroelectric liquid crystal spatial light modulator

    SciTech Connect

    Das, Abhijit; Boruah, Bosanta R.

    2014-04-15

    In this work we describe laser beam scanning using a ferroelectric liquid crystal spatial light modulator. Commercially available ferroelectric liquid crystal spatial light modulators are capable of displaying 85 colored images in 1 s using a time dithering technique. Each colored image, in fact, comprises 24 single bit (black and white) images displayed sequentially. We have used each single bit image to write a binary phase hologram. For a collimated laser beam incident on the hologram, one of the diffracted beams can be made to travel along a user defined direction. We have constructed a beam scanner employing the above arrangement and demonstrated its use to scan a single laser beam in a laser scanning optical sectioning microscope setup.

  4. A fast multispectral light synthesiser based on LEDs and a diffraction grating.

    PubMed

    Belušič, Gregor; Ilić, Marko; Meglič, Andrej; Pirih, Primož

    2016-01-01

    Optical experiments often require fast-switching light sources with adjustable bandwidths and intensities. We constructed a wavelength combiner based on a reflective planar diffraction grating and light emitting diodes with emission peaks from 350 to 630 nm that were positioned at the angles corresponding to the first diffraction order of the reversed beam. The combined output beam was launched into a fibre. The spacing between 22 equally wide spectral bands was about 15 nm. The time resolution of the pulse-width modulation drivers was 1 ms. The source was validated with a fast intracellular measurement of the spectral sensitivity of blowfly photoreceptors. In hyperspectral imaging of Xenopus skin circulation, the wavelength resolution was adequate to resolve haemoglobin absorption spectra. The device contains no moving parts, has low stray light and is intrinsically capable of multi-band output. Possible applications include visual physiology, biomedical optics, microscopy and spectroscopy. PMID:27558155

  5. A fast multispectral light synthesiser based on LEDs and a diffraction grating

    NASA Astrophysics Data System (ADS)

    Belušič, Gregor; Ilić, Marko; Meglič, Andrej; Pirih, Primož

    2016-08-01

    Optical experiments often require fast-switching light sources with adjustable bandwidths and intensities. We constructed a wavelength combiner based on a reflective planar diffraction grating and light emitting diodes with emission peaks from 350 to 630 nm that were positioned at the angles corresponding to the first diffraction order of the reversed beam. The combined output beam was launched into a fibre. The spacing between 22 equally wide spectral bands was about 15 nm. The time resolution of the pulse-width modulation drivers was 1 ms. The source was validated with a fast intracellular measurement of the spectral sensitivity of blowfly photoreceptors. In hyperspectral imaging of Xenopus skin circulation, the wavelength resolution was adequate to resolve haemoglobin absorption spectra. The device contains no moving parts, has low stray light and is intrinsically capable of multi-band output. Possible applications include visual physiology, biomedical optics, microscopy and spectroscopy.

  6. A fast multispectral light synthesiser based on LEDs and a diffraction grating

    PubMed Central

    Belušič, Gregor; Ilić, Marko; Meglič, Andrej; Pirih, Primož

    2016-01-01

    Optical experiments often require fast-switching light sources with adjustable bandwidths and intensities. We constructed a wavelength combiner based on a reflective planar diffraction grating and light emitting diodes with emission peaks from 350 to 630 nm that were positioned at the angles corresponding to the first diffraction order of the reversed beam. The combined output beam was launched into a fibre. The spacing between 22 equally wide spectral bands was about 15 nm. The time resolution of the pulse-width modulation drivers was 1 ms. The source was validated with a fast intracellular measurement of the spectral sensitivity of blowfly photoreceptors. In hyperspectral imaging of Xenopus skin circulation, the wavelength resolution was adequate to resolve haemoglobin absorption spectra. The device contains no moving parts, has low stray light and is intrinsically capable of multi-band output. Possible applications include visual physiology, biomedical optics, microscopy and spectroscopy. PMID:27558155

  7. Light coupling in a Scotch tape waveguide via an integrated metal diffraction grating.

    PubMed

    Barrios, Carlos Angulo; Canalejas-Tejero, Víctor

    2016-01-15

    We report on the first demonstration of a flexible optical waveguide interconnecting device made of a general purpose pressure-sensitive adhesive (PSA) tape embedding nanopatterned Al thin film diffractive grating couplers. The diffractive elements allow selected broadband light to be perpendicularly coupled/decoupled into/from a PSA tape waveguide in which they are integrated. Waveguide losses and coupling efficiency are evaluated. The versatility and low cost of the used materials make the presented configuration very promising for cost-effective, ready-to-use short-distance optical interconnections.

  8. Reducing the diffraction artifacts while implementing a phase function on a spatial light modulator.

    PubMed

    Benoît-Pasanau, Céline; Goudail, François; Chavel, Pierre; Cano, Jean-Paul; Ballet, Jérôme

    2011-02-01

    Spatial light modulators are often used to implement phase modulation. Since they are pixelated, the phase function is usually approximated by a regularly sampled piecewise constant function, and the periodicity of the pixel sampling generates annoying diffraction peaks. We theoretically investigate two pixelation techniques: the isophase method and a new nonperiodic method derived from the Voronoi tessellation technique. We show that, for a suitable choice of parameters, the diffraction peaks disappear and are replaced by a smoothly varying halo. We illustrate the potential of these two techniques for implementing a lens function and wavefront correction. PMID:21283242

  9. Anisotropic light diffraction in crystals with a large acoustic-energy walk-off

    NASA Astrophysics Data System (ADS)

    Balakshy, V. I.; Voloshin, A. S.; Molchanov, V. Ya.

    2014-11-01

    The influence of energy walk-off in an acoustic beam on the characteristic of anisotropic Bragg diffraction of light has been investigated by the example of paratellurite crystal. The angular and frequency characteristics of acousto-optic diffraction have been calculated in wide ranges of ultrasound frequencies and Bragg angles using the modified Raman-Nath equations. It is shown that the walk-off of an acoustic beam may change (either widen or narrow) significantly the frequency and angular ranges. The calculation results have been experimentally checked on an acousto-optic cell made of 10.5°-cut paratellurite crystal.

  10. Bragg diffraction for normal and obliquely circularly polarized light due a new chiral mixture

    NASA Astrophysics Data System (ADS)

    Castro-Garay, P.; Manzanares-Martinez, J.; Corella-Madueño, A.; Rosas-Burgos, A.; Lizola, Josue; Clark, Marielena; Palma, Lillian

    2015-09-01

    We have found experimentally the transmittance of normal incident circularly polarized light due to new chiral mixture that was distorted by electric field. The chiral mixture was achieved by mixtures of two nematic liquid crystals (5OCB and 5CB) and S-1-bromo-2-methylbutane. We have found a regime of circular Bragg diffraction for certain values of concentrations and thickness. Optical diffraction phenomenon have received particular attention in research for optical and electro-optical applications, such as low -voltage modulators, reflective phase gratings and smart reflectors.

  11. Two-mirrored galvanometer laser light sheet generator

    NASA Technical Reports Server (NTRS)

    Leighty, B. D.; Franke, J. M.; Jones, S. B.; Rhodes, D. B.

    1988-01-01

    Light sheets generated with either laser or noncoherent sources have found widespread application to flow visualization. Previous light sheet generating systems were usually dedicated to a specific viewing geometry. The technique with the most flexibility is the galvanometer mirror based laser light sheet system. A two-mirrored system was designed and developed to provide flexibility and adaptability to a wide range of applications. The design includes the capability to control the size and location of the laser light sheet in real time, to generate horizontal or vertical sheets, to sweep the sheet repeatedly through a volume, to generate multiple sheets with controllable separation and to rotate single or multiple laser light sheets. The system is capable of producing up to 12 sheets of laser light at an angular divergence of + or - 20 degrees. Maximum scan rate of any one line is 500 Hertz. This system has proven to be uniquely versatile and a patent has been applied for.

  12. Laser and light therapies for the treatment of nail psoriasis.

    PubMed

    Maranda, Eric L; Nguyen, Austin H; Lim, Victoria M; Hafeez, Farhaan; Jimenez, Joaquin J

    2016-08-01

    Psoriatic involvement of the nail is notoriously refractory to conventional therapy. Nail psoriasis has a high incidence amongst patients with psoriasis. It remains a significant cosmetic problem and thus, has a significant impact on quality of life. More recently, light and laser therapies have emerged as modalities for treatment of nail psoriasis. In this study, the efficacies of light and laser therapies are systematically reviewed. Light therapies involve ultraviolet light (with or without photosensitizers) or intense pulsed light. Alternatively, laser therapy in nail psoriasis is primarily administered using a 595-nm pulsed dye laser. These modalities have demonstrated significant improvement in psoriatic nail lesions, and even complete resolution in some cases. Both laser and light modalities have also been tested in combination with other systemic or topical therapeutics, with variable improvement in efficacy. Both laser and light therapies are generally well tolerated. Side-effects of light therapies include hyperpigmentation, itching and erythema; whereas, side-effects of laser therapy are more frequent and include pain, purpura/petechiae and hyperpigmentation. Patterns of response to therapy were also seen based on presenting characteristics of the nail lesions: subungual hyperkeratosis and onycholysis appeared to be the most responsive to therapy, while nail pitting was the most resistant. Light or laser therapies have the potential to be an efficient and cost-effective in-office based treatment for nail psoriasis. However, more large-scale clinical trials are needed to assess their efficacy, particularly in combination with other therapeutic modalities. PMID:27226341

  13. Robotic visible-light laser adaptive optics

    NASA Astrophysics Data System (ADS)

    Baranec, Christoph; Riddle, Reed; Law, Nicholas; Ramaprakash, A. N.; Tendulkar, Shriharsh; Bui, Khanh; Burse, Mahesh; Chordia, Pravin; Das, Hillol; Dekany, Richard; Kulkarni, Shrinivas; Punnadi, Sujit

    2013-12-01

    Robo-AO is the first autonomous laser adaptive optics system and science instrument operating on sky. With minimal human oversight, the system robotically executes large scale surveys, monitors long-term astrophysical dynamics and characterizes newly discovered transients, all at the visible diffraction limit. The adaptive optics setup time, from the end of the telescope slew to the beginning of an observation, is a mere ~50-60 s, enabling over 200 observations per night. The first of many envisioned systems has finished 58 nights of science observing at the Palomar Observatory 60-inch (1.5 m) telescope, with over 6,400 robotic observations executed thus far. The system will be augmented in late 2013 with a low-noise wide field infrared camera, which doubles as a tip-tilt sensor, to widen the spectral bandwidth of observations and increase available sky coverage while also enabling deeper visible imaging using adaptive-optics sharpened infrared tip-tilt guide sources. Techniques applicable to larger telescope systems will also be tested: the infrared camera will be used to demonstrate advanced multiple region-of-interest tip-tilt guiding methods, and a visitor instrument port will be used for evaluation of other instrumentation, e.g. single-mode and photonic fibers to feed compact spectrographs.

  14. Laser light: waves of the future.

    PubMed

    Sweet, C A

    1997-01-01

    The use of lasers is becoming more prevalent in the health care arena. Lasers can perform functions from lightening spider veins to correcting nearsightedness. Nurses must become familiar with lasers as 21st century medicine becomes a reality.

  15. Diffuse Reflection of Laser Light From Clouds

    NASA Technical Reports Server (NTRS)

    Cahalan, R. F.; Davis, A.; McGill, M.

    1999-01-01

    Laser light reflected from an aqueous suspension of particles or "cloud" with known thickness and particle size distribution defines the "cloud radiative Green's function", G. G is sensitive to cloud thickness, allowing retrieval of that important quantity. We describe a laboratory simulation of G, useful in design of an offbeam Lidar instrument for remote sensing of cloud thickness. Clouds of polystyrene microspheres suspended in water are analogous to real clouds of water droplets suspended in air. The size distribution extends from 0.5 microns to 25 microns, roughly lognormal, similar to real clouds. Density of suspended spheres is adjusted so photon mean-free-path is about 10 cm, 1000 times smaller than in real clouds. The light source is a Nd:YAG laser at 530 nm. Detectors are flux and photon-counting PMTs, with a glass probe for precise positioning. A Labview 5 VI controls position and data acquisition, via an NI Motion Control board connected to a stepper motor driving an Edmund linear slider,and a 16-channel 16-bit NI-DAQ board. The stepper motor is accurate to 10 microns. Step size is selectable. Far from the beam, the rate of exponential increase in the beam direction scales as expected from diffusion theory, linearly with cloud thickness, and inversely as the square root of the reduced optical thickness, independent of particle size. Nearer the beam the signal increases faster than exponential and depends on particle size. Results verify 3D Monte Carlo simulations that demonstrate detectability of remotely sensed offbeam returns, without filters at night, with narrow bandpass filter in day.

  16. Extracting conformational structure information of benzene molecules via laser-induced electron diffraction.

    PubMed

    Ito, Yuta; Wang, Chuncheng; Le, Anh-Thu; Okunishi, Misaki; Ding, Dajun; Lin, C D; Ueda, Kiyoshi

    2016-05-01

    We have measured the angular distributions of high energy photoelectrons of benzene molecules generated by intense infrared femtosecond laser pulses. These electrons arise from the elastic collisions between the benzene ions with the previously tunnel-ionized electrons that have been driven back by the laser field. Theory shows that laser-free elastic differential cross sections (DCSs) can be extracted from these photoelectrons, and the DCS can be used to retrieve the bond lengths of gas-phase molecules similar to the conventional electron diffraction method. From our experimental results, we have obtained the C-C and C-H bond lengths of benzene with a spatial resolution of about 10 pm. Our results demonstrate that laser induced electron diffraction (LIED) experiments can be carried out with the present-day ultrafast intense lasers already. Looking ahead, with aligned or oriented molecules, more complete spatial information of the molecule can be obtained from LIED, and applying LIED to probe photo-excited molecules, a "molecular movie" of the dynamic system may be created with sub-Ångström spatial and few-ten femtosecond temporal resolutions. PMID:27462650

  17. Extracting conformational structure information of benzene molecules via laser-induced electron diffraction

    PubMed Central

    Ito, Yuta; Wang, Chuncheng; Le, Anh-Thu; Okunishi, Misaki; Ding, Dajun; Lin, C. D.; Ueda, Kiyoshi

    2016-01-01

    We have measured the angular distributions of high energy photoelectrons of benzene molecules generated by intense infrared femtosecond laser pulses. These electrons arise from the elastic collisions between the benzene ions with the previously tunnel-ionized electrons that have been driven back by the laser field. Theory shows that laser-free elastic differential cross sections (DCSs) can be extracted from these photoelectrons, and the DCS can be used to retrieve the bond lengths of gas-phase molecules similar to the conventional electron diffraction method. From our experimental results, we have obtained the C-C and C-H bond lengths of benzene with a spatial resolution of about 10 pm. Our results demonstrate that laser induced electron diffraction (LIED) experiments can be carried out with the present-day ultrafast intense lasers already. Looking ahead, with aligned or oriented molecules, more complete spatial information of the molecule can be obtained from LIED, and applying LIED to probe photo-excited molecules, a “molecular movie” of the dynamic system may be created with sub-Ångström spatial and few-ten femtosecond temporal resolutions. PMID:27462650

  18. Extracting conformational structure information of benzene molecules via laser-induced electron diffraction

    DOE PAGESBeta

    Ito, Yuta; Wang, Chuncheng; Le, Anh-Thu; Okunishi, Misaki; Ding, Dajun; Lin, C. D.; Ueda, Kiyoshi

    2016-05-01

    Here, we have measured the angular distributions of high energy photoelectrons of benzene molecules generated by intense infrared femtosecond laser pulses. These electrons arise from the elastic collisions between the benzene ions with the previously tunnel-ionized electrons that have been driven back by the laser field. Theory shows that laser-free elastic differential cross sections (DCSs) can be extracted from these photoelectrons, and the DCS can be used to retrieve the bond lengths of gas-phase molecules similar to the conventional electron diffraction method. From our experimental results, we have obtained the C-C and C-H bond lengths of benzene with a spatialmore » resolution of about 10 pm. Our results demonstrate that laser induced electron diffraction (LIED) experiments can be carried out with the present-day ultrafast intense lasers already. Looking ahead, with aligned or oriented molecules, more complete spatial information of the molecule can be obtained from LIED, and applying LIED to probe photo-excited molecules, a “molecular movie” of the dynamic system may be created with sub-A°ngstrom spatial and few-ten femtosecond temporal resolutions.« less

  19. Creation of vector beams from a polarization diffraction grating using a programmable liquid crystal spatial light modulator and a q-plate

    NASA Astrophysics Data System (ADS)

    Badham, Katherine Emily

    This thesis presents the ability of complete polarization control of light to create a polarization diffraction grating (PDG). This system has the ability to create diffracted light with each order having a separate high-order polarization state in one location on the optical axis. First, an external Excel program is used to create a grating phase profile from userspecified target diffraction orders. High-order vector beams in this PDG are created using a combination of two devices---a liquid crystal spatial light modulator (LC-SLM) manufactured by Seiko Epson, and a tunable q -plate from Citizen Holdings Co. The transmissive SLM is positioned in an optical setup with a reflective architecture allowing control over both the horizontal and vertical components of the laser beam. The SLM has its LC director oriented vertically only affecting the vertically polarized state, however, the optical setup allows modulation of both vertical and horizontal components by the use of a quarter-wave plate (QWP) and a mirror to rotate the polarizations 90 degrees. Each half of the SLM is encoded with an anisotropic phase-only diffraction grating which are superimposed to create a select number of orders with the desired polarization states and equally distributed intensity. The technique of polarimetry is used to confirm the polarization state of each diffraction order. The q-plate is an inhomogeneous birefringent waveplate which has the ability to convert zero-order vector beams into first-order vector beams. The physical placement of this device into the system converts the orders with zero-order polarization states to first-order polarization states. The light vector patterns of each diffraction order confirm which first-order polarization state of is produced. A specially made PDG sextuplicator is encoded onto the SLM to generate six diffraction orders with separate states of polarization.

  20. Scattering of white light from levitated oblate water drops near rainbows and other diffraction catastrophes.

    PubMed

    Simpson, H J; Marston, P L

    1991-08-20

    Oblate drops of water illuminated perpendicular to their symmetry axis generate a hyperbolic-umbilic diffraction catastrophe near the primary rainbow [P. L. Marston and E. H. Trinh, Nature London 312, 529-531 (1984)]. Observations were made of this diffraction catastrophe generated by white-light illumination of acoustically levitated drops of water in air. The observations suggest what generalized rainbows would look like if they were produced in nature when sunlight illuminates large raindrops. Unlike the usual rainbow arc, the transverse cusp of the unfolded catastrophe is not distinctly colored. The hyperbolic-umbilic focal section is distinctly colored as is another diffraction catastrophe generated in the rainbow region when the drop is highly oblate. PMID:20706412

  1. High coherent bi-chromatic laser with gigahertz splitting produced by the high diffraction orders of acousto-optic modulator used for coherent population trapping experiments.

    PubMed

    Yun, Peter; Tan, Bozhong; Deng, Wei; Gu, Sihong

    2011-12-01

    To prepare the coherent population trapping (CPT) states with rubidium and cesium, the commonly used atoms in CPT studies, a coherent bi-chromatic light field with frequency difference of several GHz is a basic requirement. With a 200 MHz center frequency acousto-optic modulator (AOM), we have realized bi-chromatic laser fields with several GHz frequency splits through high diffraction orders. We have experimentally studied the coherence between two frequency components of a bi-chromatic laser beam, which is composed of ±6 orders with frequency split of 3 GHz diffracted from the same laser beam, and the measured residual phase noise is Δφ(2)<0.019 rad(2). The bi-chromatic laser fields were used to prepare CPT states with (85)Rb and (87)Rb atoms, and high contrast CPT signals were obtained. For CPT states preparation, our study result shows that it is a feasible approach to generate the bi-chromatic light field with larger frequency splits through high diffraction orders of AOM.

  2. Twin-Mirrored-Galvanometer Laser-Light-Sheet Generator

    NASA Technical Reports Server (NTRS)

    Rhodes, David B.; Franke, John M.; Jones, Stephen B.; Leighty, Bradley D.

    1991-01-01

    Multiple, rotating laser-light sheets generated to illuminate flows in wind tunnels. Designed and developed to provide flexibility and adaptability to wide range of applications. Design includes capability to control size and location of laser-light sheet in real time, to generate horizontal or vertical sheets, to sweep sheet repeatedly through volume, to generate multiple sheets with controllable separation, and to rotate single or multiple laser-light sheets. Includes electronic equipment and laser mounted on adjustable-height platform. Twin-mirrored galvanometer unit supported by tripod to reduce vibration. Other possible applications include use in construction industry to align beams of building. Artistic or display applications also possible.

  3. NASA Laser Light Scattering Advanced Technology Development Workshop, 1988

    NASA Technical Reports Server (NTRS)

    Meyer, William V. (Editor)

    1989-01-01

    The major objective of the workshop was to explore the capabilities of existing and prospective laser light scattering hardware and to assess user requirements and needs for a laser light scattering instrument in a reduced gravity environment. The workshop addressed experimental needs and stressed hardware development.

  4. [Wound healing after laser and red light irradiation].

    PubMed

    Hutschenreiter, G; Haina, D; Paulini, K; Schumacher, G

    1980-04-01

    Laser irradiation and red light irradiation, daily 2 respectively 4 J/cm2, do not bring any acceleration of wound healing in rats. No significant effect was evident in the cell pattern of wounds during various phases of healing through the irradiation. The tensile strength of cicatrices increased by laser irradiation, but not by red light irradiation (monochromatic lambda = 633 nm).

  5. Hybrid proton acceleration scheme using relativistic intense laser light

    SciTech Connect

    Andreev, A. A.; Platonov, K. Yu.; Schnuerer, M.; Prasad, R.; Ter-Avetisyan, S.

    2013-03-15

    Ion acceleration phenomena at relativistic intense laser interaction with thin foil targets are studied to find an efficient laser-target interaction concept at the conditions, where neither the ponderomotive pressure of the laser light nor the hot electron pressure is negligible. Particle in cell simulations and the analytical model are allowing to predict optimum laser-target parameters and suggesting a significant increase of proton energy if a hybrid proton acceleration scheme is used. In the proposed scenario, the laser polarisation is changed during the acceleration process: First with circularly polarised laser light the target is accelerated as a whole by the ponderamotive pressure, and then with linearly polarised laser light the electrons are heated which additionally increases the accelerating field. The calculations are in good agreement with experimental findings.

  6. Determining the size distribution of core-shell spheres and other complex particles by laser diffraction.

    PubMed

    Lagasse, R R; Richards, D Wayne

    2003-11-01

    The goal of this work is to determine the size distribution of hollow glass spheres by laser diffraction, an experiment which involves measuring angle-dependent scattering of light from particles dispersed in a liquid. The proprietary software supplied with commercial instruments is not strictly applicable to our two-layer, glass-shell, hollow-core spheres because it requires that the particles have spatially homogeneous properties. We therefore developed Fortran code to compute the scattering from core-shell spherical particles. The results show that the scattering from representative hollow glass particles diverges from homogeneous sphere scattering when the radius decreases from 10 to 3 microm. Additionally, scattering measurements on two core-shell hollow glass powders were analyzed using the exact core-shell optical model and homogeneous sphere approximations. In both cases, the size distribution determined using the exact core-shell model differs from that determined using the homogeneous-sphere approximation when the distribution covers radii smaller than about 10 microm, as expected. The size distribution based on the exact core-shell optical model was determined using a new algorithm. Although the basic equations used in the algorithm have been published previously, they are developed here in a different form, which can be implemented using Fortran and MatLab routines available commercially and in the public domain. This algorithm could be used to determine the size distribution of other kinds of particles, such as cylindrical rods, as long as their angle-dependent scattering could be computed. PMID:14554168

  7. Spatial coherence of the generalized diffraction-filtered resonator copper vapor laser.

    PubMed

    Prakash, O; Shukla, P K; Dixit, S K; Chatterjee, S; Vora, H S; Bhatnagar, R

    1998-11-20

    The results of a study on the spatial coherence of a generalized diffraction-filtered resonator (GDFR) copper vapor laser (CVL) for various magnifications are presented. The coherence width and output power are compared with that of unstable resonators (UR's) of equivalent magnifications. It is established, by use of reversal shear interferometry, that the GDFR CVL beam has better spatial coherence and average power characteristics than the UR CVL beam for equivalent resonator magnifications. PMID:18301614

  8. Angularly separated harmonic generation from intense laser interaction with blazed diffraction gratings.

    PubMed

    Yeung, M; Zepf, M; Geissler, M; Dromey, B

    2011-06-15

    We made numerical simulations of the generation of narrowband beams of extreme ultraviolet radiation from intense laser interaction with a blazed grating surface. Strong fifth harmonic emission into its blazed diffraction order was observed as well as heavy suppression of the fundamental frequency with comparison to a typical harmonic spectrum from a flat target. The results demonstrate a new highly efficient method of generating near-monochromatic harmonics from the fundamental with minimal effect on the pulse duration.

  9. Damped and thermal motion of laser-aligned hydrated macromolecule beams for diffraction.

    PubMed

    Starodub, D; Doak, R B; Schmidt, K; Weierstall, U; Wu, J S; Spence, J C H; Howells, M; Marcus, M; Shapiro, D; Barty, A; Chapman, H N

    2005-12-22

    We consider a monodispersed Rayleigh droplet beam of water droplets doped with proteins. An intense infrared laser is used to align these droplets. The arrangement has been proposed for electron- and x-ray-diffraction studies of proteins which are difficult to crystallize. This paper considers the effect of thermal fluctuations on the angular spread of alignment in thermal equilibrium, and relaxation phenomena, particularly the damping of oscillations excited as the molecules enter the field. The possibility of adiabatic alignment is also considered. We find that damping times in a high-pressure gas cell as used in x-ray-diffraction experiments are short compared with the time taken for molecules to traverse the beam and that a suitably shaped field might be used for electron-diffraction experiments in vacuum to provide adiabatic alignment, thus obviating the need for a damping gas cell.

  10. Laser microfluidics: fluid actuation by light

    NASA Astrophysics Data System (ADS)

    Delville, Jean-Pierre; de Saint Vincent, Matthieu Robert; Schroll, Robert D.; Chraïbi, Hamza; Issenmann, Bruno; Wunenburger, Régis; Lasseux, Didier; Zhang, Wendy W.; Brasselet, Etienne

    2009-03-01

    The development of microfluidic devices is still hindered by the lack of robust fundamental building blocks that constitute any fluidic system. An attractive approach is optical actuation because light field interaction is contactless and dynamically reconfigurable, and solutions have been anticipated through the use of optical forces to manipulate microparticles in flows. Following the concept of an 'optical chip' advanced from the optical actuation of suspensions, we propose in this survey new routes to extend this concept to microfluidic two-phase flows. First, we investigate the destabilization of fluid interfaces by the optical radiation pressure and the formation of liquid jets. We analyze the droplet shedding from the jet tip and the continuous transport in laser-sustained liquid channels. In the second part, we investigate a dissipative light-flow interaction mechanism consisting in heating locally two immiscible fluids to produce thermocapillary stresses along their interface. This opto-capillary coupling is implemented in adequate microchannel geometries to manipulate two-phase flows and propose a contactless optical toolbox including valves, droplet sorters and switches, droplet dividers or droplet mergers. Finally, we discuss radiation pressure and opto-capillary effects in the context of the 'optical chip' where flows, channels and operating functions would all be performed optically on the same device.

  11. Slowing and cooling atoms in isotropic laser light

    NASA Astrophysics Data System (ADS)

    Ketterle, Wolfgang; Martin, Alex; Joffe, Michael A.; Pritchard, David E.

    1992-10-01

    We demonstrate cooling and slowing of atoms in isotropic laser light. As the atoms slow, they compensate for their changing Doppler shift by preferentially absorbing photons at a varying angle to their direction of motion, resulting in a continuous beam of slow atoms unperturbed by an intense slowing laser beam. We point out several novel features of slowing and cooling in isotropic light, and show that it can be superior to cooling with directed laser beams.

  12. Immobilization of biomolecules onto surfaces according to ultraviolet light diffraction patterns

    SciTech Connect

    Bjoern Petersen, Steffen; Kold di Gennaro, Ane; Neves-Petersen, Maria Teresa; Skovsen, Esben; Parracino, Antonietta

    2010-10-01

    We developed a method for immobilization of biomolecules onto thiol functionalized surfaces according to UV diffraction patterns. UV light-assisted molecular immobilization proceeds through the formation of free, reactive thiol groups that can bind covalently to thiol reactive surfaces. We demonstrate that, by shaping the pattern of the UV light used to induce molecular immobilization, one can control the pattern of immobilized molecules onto the surface. Using a single-aperture spatial mask, combined with the Fourier transforming property of a focusing lens, we show that submicrometer (0.7 {mu}m) resolved patterns of immobilized prostate-specific antigen biomolecules can be created. If a dual-aperture spatial mask is used, the results differ from the expected Fourier transform pattern of the mask. It appears as a superposition of two diffraction patterns produced by the two apertures, with a fine structured interference pattern superimposed.

  13. Theoretical study of the anisotropic diffraction of light waves by acoustic waves in lithium niobate crystals.

    PubMed

    Rouvaen, J M; Waxin, G; Gazalet, M G; Bridoux, E

    1990-03-20

    The anisotropic diffraction of light by high frequency longitudinal ultrasonic waves in the tangential phase matching configuration may present some definite advantages over the same interaction using transverse acoustic waves. A systematic search for favorable crystal cuts in lithium niobate was worked out. The main results of this study are reported here; they enable the choice of the best configuration for a given operating center frequency.

  14. Light pressure acceleration with frequency-tripled laser pulse

    SciTech Connect

    Wang, Xiaofeng; Shen, Baifei E-mail: zhxm@siom.ac.cn; Zhang, Xiaomei E-mail: zhxm@siom.ac.cn; Ji, Liangliang; Wang, Wenpeng; Zhao, Xueyan; Xu, Jiancai; Yu, Yahong; Yi, Longqing; Shi, Yin; Xu, Tongjun; Zhang, Lingang

    2014-08-15

    Light pressure acceleration of ions in the interaction of the frequency-tripled (3ω) laser pulse and foil target is studied, and a promising method to increase accelerated ion energy is shown. Results show that at a constant laser energy, much higher ion energy peak value is obtained for 3ω laser compared with that using the fundamental frequency laser. The effect of energy loss during frequency conversion on ion acceleration is considered, which may slightly decrease the acceleration effect.

  15. Fraunhofer diffraction of light with orbital angular momentum by a slit.

    PubMed

    Ferreira, Queila S; Jesus-Silva, Alcenísio J; Fonseca, Eduardo J S; Hickmann, Jandir M

    2011-08-15

    We study the Fraunhofer diffraction problem while taking into account the orbital angular momentum of light. In this case, the phase singularity of the light beam is incident on the slit in two different cases: in one, it is incident slightly above the slit, and in the other it is centered on the slit. We observed that the symmetry and the fringe formation in the interference pattern strongly depend on the amount of orbital angular momentum and the slit position in relation to the beam.

  16. Evaluation of photoelectric processes in photorefractive crystals via the exposure characteristics of light diffraction.

    PubMed

    Kadys, A; Gudelis, V; Sudzius, M; Jarasiunas, K

    2005-01-12

    We demonstrate a novel way to analyse carrier recombination and transport processes in photorefractive semiconductors via the exposure characteristics of light induced diffraction. The results of a picosecond four-wave mixing on free carrier gratings in semi-insulating GaAs crystals at various grating periods and modulation depths of a light interference pattern are discussed. The role of a deep-trap recharging in carrier diffusion and recombination is sensitively revealed through a feedback effect of a space-charge field to non-equilibrium carrier transport.

  17. High resolution light diffraction tomography: nearfield measurements of 10 MHz continuous wave ultrasound

    PubMed

    Almqvist; Holm; Jansson; Persson; Lindstrom

    1999-06-01

    Light diffraction tomography is an ultrasound measurement method that offers possibilities to make high spatial resolution measurements. The aim of this study was to investigate the spatial resolution of light diffraction tomography by characterizing the complex pressure and phase patterns 0.5-1 mm from the surface of a 5 mm diameter 10 MHz ultrasound transducer. Three different transducers were measured with a detection width of 5 microm, sample distances of 20-40 microm and 50-100 projections/180 degrees. They were excited with a 10 Vpp CW-signal. To verify the results the optical measurements were compared with 75 microm diameter hydrophone measurements and with theoretical calculations. The light diffraction tomography results show very good agreement with the hydrophone measurements and pressure peaks separated 160 microm were resolved. Comparison with the theoretical calculation shows that small distortions, caused by defects in the matching layer or in the piezo-electric disc, disturb the symmetric ring-pattern characteristic of an ideal piston source. PMID:10499805

  18. Diffractive intermediate layer enables broadband light trapping for high efficiency ultrathin c-Si tandem cells

    SciTech Connect

    Li, Guijun Ho, Jacob Y. L.; Li, He; Kwok, Hoi-Sing

    2014-06-09

    Light management through the intermediate reflector in the tandem cell configuration is of great practical importance for achieving high stable efficiency and also low cost production. So far, however, the intermediate reflectors employed currently are mainly focused on the light absorption enhancement of the top cell. Here, we present a diffractive intermediate layer that allows for light trapping over a broadband wavelength for the ultrathin c-Si tandem solar cell. Compared with the standard intermediate reflector, this nanoscale architectural intermediate layer results in a 35% and 21% remarkable enhancement of the light absorption in the top (400–800 nm) and bottom (800–1100 nm) cells simultaneously, and ultrathin c-Si tandem cells with impressive conversion efficiency of 13.3% are made on the glass substrate.

  19. 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.

  20. Imaging live cell in micro-liquid enclosure by X-ray laser diffraction

    NASA Astrophysics Data System (ADS)

    Kimura, Takashi; Joti, Yasumasa; Shibuya, Akemi; Song, Changyong; Kim, Sangsoo; Tono, Kensuke; Yabashi, Makina; Tamakoshi, Masatada; Moriya, Toshiyuki; Oshima, Tairo; Ishikawa, Tetsuya; Bessho, Yoshitaka; Nishino, Yoshinori

    2014-01-01

    Emerging X-ray free-electron lasers with femtosecond pulse duration enable single-shot snapshot imaging almost free from sample damage by outrunning major radiation damage processes. In bioimaging, it is essential to keep the sample close to its natural state. Conventional high-resolution imaging, however, suffers from severe radiation damage that hinders live cell imaging. Here we present a method for capturing snapshots of live cells kept in a micro-liquid enclosure array by X-ray laser diffraction. We place living Microbacterium lacticum cells in an enclosure array and successively expose each enclosure to a single X-ray laser pulse from the SPring-8 Angstrom Compact Free-Electron Laser. The enclosure itself works as a guard slit and allows us to record a coherent diffraction pattern from a weakly-scattering submicrometre-sized cell with a clear fringe extending up to a 28-nm full-period resolution. The reconstructed image reveals living whole-cell structures without any staining, which helps advance understanding of intracellular phenomena.

  1. Femtosecond laser induced tunable surface transformations on (111) Si aided by square grids diffraction

    SciTech Connect

    Han, Weina; Jiang, Lan; Li, Xiaowei Liu, Yang

    2015-12-21

    We report an extra freedom to modulate the femtosecond laser energy distribution to control the surface ablated structures through a copper-grid mask. Due to the reduced deposited pulse energy by changing the scanning speed or the pulse fluence, a sequential evolution of three distinctly different surface patterns with periodic distributions is formed, namely, striped ripple lines, ripple microdots, and surface modification. By changing the scanning speed, the number of the multiple dots in a lattice can be modulated. Moreover, by exploring the ablation process through the copper grid mask, it shows an abnormal enhanced ablation effect with strong dependence of the diffraction-aided fs laser ablated surface structures on polarization direction. The sensitivity shows a quasi-cosinusoid-function with a periodicity of π/2. Particularly, the connection process of striped ripple lines manifests a preferential formation direction with the laser polarization.

  2. Femtosecond laser induced tunable surface transformations on (111) Si aided by square grids diffraction

    NASA Astrophysics Data System (ADS)

    Han, Weina; Jiang, Lan; Li, Xiaowei; Liu, Yang; Lu, Yongfeng

    2015-12-01

    We report an extra freedom to modulate the femtosecond laser energy distribution to control the surface ablated structures through a copper-grid mask. Due to the reduced deposited pulse energy by changing the scanning speed or the pulse fluence, a sequential evolution of three distinctly different surface patterns with periodic distributions is formed, namely, striped ripple lines, ripple microdots, and surface modification. By changing the scanning speed, the number of the multiple dots in a lattice can be modulated. Moreover, by exploring the ablation process through the copper grid mask, it shows an abnormal enhanced ablation effect with strong dependence of the diffraction-aided fs laser ablated surface structures on polarization direction. The sensitivity shows a quasi-cosinusoid-function with a periodicity of π/2. Particularly, the connection process of striped ripple lines manifests a preferential formation direction with the laser polarization.

  3. Reflection of femtosecond laser light in multipulse ablation of metals

    SciTech Connect

    Vorobyev, A. Y.; Guo Chunlei

    2011-08-15

    The shot-to-shot reflectance of high-intensity laser light is studied as a function of both the number of laser shots and laser fluence in multipulse ablation of a metal when the irradiated surface undergoes structural changes from an initially smooth surface to a deep crater. Our study shows that the reflectance of the irradiated surface significantly decreases due to the high intensity of laser pulses and the laser-induced surface structures in ablation regimes typically used for femtosecond laser processing of materials. The high-intensity effect dominates in the reflection reduction at low numbers of laser shots when laser-induced surface structures do not cause the reflectance to decrease noticeably. With increasing the number of laser shots, the structural effect comes into play, and both high-intensity and structural effects quickly reduce the reflectance of the sample to a low value.

  4. Design and application of a new modular adapter for laser diffraction characterization of inhalation aerosols.

    PubMed

    de Boer, A H; Gjaltema, D; Hagedoorn, P; Schaller, M; Witt, W; Frijlink, H W

    2002-12-01

    An inhaler adapter has been designed for the characterization of the aerosol clouds from medical aerosol generators such as nebulizers, dry powder inhalers (dpis) and metered dose inhalers (mdis) with laser diffraction technology. The adapter has a pre-separator, for separation of large particles (i.e. carrier crystals) from the aerosol cloud before it is exposed to the laser beam. It also has a fine particle collector for measuring the emitted mass fraction of fines by chemical detection methods after laser diffraction sizing. The closed system enables flow control through the aerosol generators and all test conditions, including ambient temperature and relative humidity, are automatically recorded. Counter flows minimize particle deposition onto the two windows for the laser beam, which make successive measurements without cleaning of these windows possible. The adapter has successfully been tested for nebulizers, mdis and dpis. In a comparative study with ten nebulizers it was found that these devices differ considerably in droplet size (distribution) of the aerosol cloud for the same 10% aqueous tobramycin solution (volume median diameters ranging from 1.25 to 3.25 microm) when they are used under the conditions recommended by the manufacturers. The droplet size distribution generated by the Sidestream (with PortaNeb compressor) is very constant during nebulization until dry running of the device. Comparative testing of dpis containing spherical pellet type of formulations for the drug (e.g. the AstraZeneca Turbuhaler) with the adapter is fast and simple. But also formulations containing larger carrier material could successfully be measured. Disintegration efficiency of a test inhaler with carrier retainment (acting as a pre-separator) could be measured quite accurately both for a colistin sulfate formulation with 16.7% of a lactose fraction 106-150 microm and for a budesonide formulation with a carrier mixture of Pharmatose 325 and 150 M. Therefore, it is

  5. Photoelectron diffraction from single oriented molecules: Towards ultrafast structure determination of molecules using x-ray free-electron lasers

    NASA Astrophysics Data System (ADS)

    Kazama, Misato; Fujikawa, Takashi; Kishimoto, Naoki; Mizuno, Tomoya; Adachi, Jun-ichi; Yagishita, Akira

    2013-06-01

    We provide a molecular structure determination method, based on multiple-scattering x-ray photoelectron diffraction (XPD) calculations. This method is applied to our XPD data on several molecules having different equilibrium geometries. Then it is confirmed that, by our method, bond lengths and bond angles can be determined with a resolution of less than 0.1 Å and 10∘, respectively. Differently from any other scenario of ultrafast structure determination, we measure the two- or three-dimensional XPD of aligned or oriented molecules in the energy range from 100 to 200 eV with a 4π detection velocity map imaging spectrometer. Thanks to the intense and ultrashort pulse properties of x-ray free-electron lasers, our approach exhibits the most probable method for obtaining ultrafast real-time structural information on small to medium-sized molecules consisting of light elements, i.e., a “molecular movie.”

  6. Large-Optics white light interferometer for laser wavefront test: apparatus and application

    NASA Astrophysics Data System (ADS)

    Luan, Zhu; Liu, Liren; Wang, Lijuan; Liu, De'an

    2008-08-01

    There is transmitting optics of 250mm aperture with about 8 microradians in SILEX system. This is often large aperture and diffraction-limited laser beam in the laser communications. Large-Optics white light interferometer using double-shearing structure has been submitted to analysis the laser wavefront before. Six optical plates of 490 millimeters apertures are manufactured now one of which is also aperture-divided so that the precision of measured wave front is higher than the full aperture design. It is suitable for measurement of minimum diffraction-limited laser wave front and any wavelength. The interference is happened between equal optical path of the reflection and the other. The plates are the basic structures which are precisely parallel or perpendicular needed for either two plates. There are several tools equipped with the interferometer including white light test source and collimators and so on to confirm the precision of several seconds angle. The apparatus and application is explained in detail in this paper. The adjustment is important for the realization of white light test.

  7. Laser wakefield accelerator based light sources: potential applications and requirements

    SciTech Connect

    Albert, F.; Thomas, A. G.; Mangles, S. P.D.; Banerjee, S.; Corde, S.; Flacco, A.; Litos, M.; Neely, D.; Viera, J.; Najmudin, Z.; Bingham, R.; Joshi, C.; Katsouleas, T.

    2015-01-15

    In this article we review the prospects of laser wakefield accelerators as next generation light sources for applications. This work arose as a result of discussions held at the 2013 Laser Plasma Accelerators Workshop. X-ray phase contrast imaging, X-ray absorption spectroscopy, and nuclear resonance fluorescence are highlighted as potential applications for laser-plasma based light sources. We discuss ongoing and future efforts to improve the properties of radiation from plasma betatron emission and Compton scattering using laser wakefield accelerators for these specific applications.

  8. The MYTHEN detector for X-ray powder diffraction experiments at the Swiss Light Source

    PubMed Central

    Bergamaschi, Anna; Cervellino, Antonio; Dinapoli, Roberto; Gozzo, Fabia; Henrich, Beat; Johnson, Ian; Kraft, Philipp; Mozzanica, Aldo; Schmitt, Bernd; Shi, Xintian

    2010-01-01

    The MYTHEN single-photon-counting silicon microstrip detector has been developed at the Swiss Light Source for time-resolved powder diffraction experiments. An upgraded version of the detector has been installed at the SLS powder diffraction station allowing the acquisition of diffraction patterns over 120° in 2θ in fractions of seconds. Thanks to the outstanding performance of the detector and to the calibration procedures developed, the quality of the data obtained is now comparable with that of traditional high-resolution point detectors in terms of FWHM resolution and peak profile shape, with the additional advantage of fast and simultaneous acquisition of the full diffraction pattern. MYTHEN is therefore optimal for time-resolved or dose-critical measurements. The characteristics of the MYTHEN detector together with the calibration procedures implemented for the optimization of the data are described in detail. The refinements of two known standard powders are discussed together with a remarkable application of MYTHEN to organic compounds in relation to the problem of radiation damage. PMID:20724787

  9. Differential near-edge coherent diffractive imaging using a femtosecond high-harmonic XUV light source.

    PubMed

    Weise, Fabian; Neumark, Daniel M; Leone, Stephen R; Gessner, Oliver

    2012-11-19

    Element-specific contrast enhancement in tabletop coherent diffractive imaging (CDI) is demonstrated by employing an ultrafast extreme ultraviolet (XUV) light source with tunable photon energy. By combining two measurements performed at energies below and above the Al L(2,3) absorption edge, the spatial autocorrelation function of a micron-scale double pinhole in a 300 nm thick aluminum foil is retrieved despite a dominant background signal from directly transmitted light across the entire range of detectable diffraction angles. The fringe visibility in the diffraction patterns is 0 below the Al L(2,3) edge, 0.53 ± 0.06 above the edge, and 0.73 ± 0.08 in the differential image that combines the two measurements. The proof-of-principle experiment demonstrates that the variations of XUV optical constants in the vicinity of an inner-shell absorption edge can be utilized to improve the chemical sensitivity and image reconstruction quality of laboratory-based ultrafast imaging experiments.

  10. Multi-wavelength speckle reduction for laser pico-projectors using diffractive optics

    NASA Astrophysics Data System (ADS)

    Thomas, Weston H.

    Personal electronic devices, such as cell phones and tablets, continue to decrease in size while the number of features and add-ons keep increasing. One particular feature of great interest is an integrated projector system. Laser pico-projectors have been considered, but the technology has not been developed enough to warrant integration. With new advancements in diode technology and MEMS devices, laser-based projection is currently being advanced for pico-projectors. A primary problem encountered when using a pico-projector is coherent interference known as speckle. Laser speckle can lead to eye irritation and headaches after prolonged viewing. Diffractive optical elements known as diffusers have been examined as a means to lower speckle contrast. Diffusers are often rotated to achieve temporal averaging of the spatial phase pattern provided by diffuser surface. While diffusers are unable to completely eliminate speckle, they can be utilized to decrease the resultant contrast to provide a more visually acceptable image. This dissertation measures the reduction in speckle contrast achievable through the use of diffractive diffusers. A theoretical Fourier optics model is used to provide the diffuser's stationary and in-motion performance in terms of the resultant contrast level. Contrast measurements of two diffractive diffusers are calculated theoretically and compared with experimental results. In addition, a novel binary diffuser design based on Hadamard matrices will be presented. Using two static in-line Hadamard diffusers eliminates the need for rotation or vibration of the diffuser for temporal averaging. Two Hadamard diffusers were fabricated and contrast values were subsequently measured, showing good agreement with theory and simulated values. Monochromatic speckle contrast values of 0.40 were achieved using the Hadamard diffusers. Finally, color laser projection devices require the use of red, green, and blue laser sources; therefore, using a

  11. Multi-point laser spark generation for internal combustion engines using a spatial light modulator

    NASA Astrophysics Data System (ADS)

    Lyon, Elliott; Kuang, Zheng; Cheng, Hua; Page, Vincent; Shenton, Tom; Dearden, Geoff

    2014-11-01

    This paper reports on a technique demonstrating for the first time successful multi-point laser-induced spark generation, which is variable in three dimensions and derived from a single laser beam. Previous work on laser ignition of internal combustion engines found that simultaneously igniting in more than one location resulted in more stable and faster combustion - a key potential advantage over conventional spark ignition. However, previous approaches could only generate secondary foci at fixed locations. The work reported here is an experimental technique for multi-point laser ignition, in which several sparks with arbitrary spatial location in three dimensions are created by variable diffraction of a pulsed single laser beam source and transmission through an optical plug. The diffractive multi-beam arrays and patterns are generated using a spatial light modulator on which computer generated holograms are displayed. A gratings and lenses algorithm is used to accurately modulate the phase of the input laser beam and create multi-beam output. The underpinning theory, experimental arrangement and results obtained are presented and discussed.

  12. Ultrafast electron diffraction from laser-aligned molecules in the gas phase

    NASA Astrophysics Data System (ADS)

    Yang, Jie

    Ultrafast electron diffraction has emerged since the end of last century, and has become an increasingly important tool for revealing great details of molecular dynamics. In comparison to spectroscopic techniques, ultrafast electron diffraction directly probes time-resolved structure of target molecules, and therefore can potentially provide "molecular movies" of the reactions being studied. These molecular movies are critical for understanding and ultimately controlling the energy conversion pathways and efficiencies of photochemical processes. In this dissertation, I have focused on ultrafast electron diffraction from gas-phase molecules, and have investigated several long-standing challenges that have been preventing researchers from being able to achieve 3-D molecular movies of photochemical reactions. The first challenge is to resolve the full 3-D structure for molecules in the gas phase. The random orientation of molecules in the gas phase smears out the diffraction signal, which results in only 1-D structural information being accessible. The second challenge lies in temporal resolution. In order to resolve coherent nuclear motions on their natural time scale, a temporal resolution of ˜200 femtosecond or better is required. However, due to experimental limitations the shortest temporal resolution that had been achieved was only a few picoseconds in early 2000, by Zewail group from Caltech. The first challenge is tackled by laser-alignment. In the first half of the dissertation, I approach this method both theoretically and experimentally, and demonstrate that by using a short laser pulse to transiently align target molecules in space, 3-D molecular structure can be reconstructed ab-initio from diffraction patterns. The second half of the dissertation presents two experiments, both of which are important steps toward imaging coherent nuclear motions in real time during photochemical reactions. The first experiment simultaneously resolves molecular alignment

  13. X-ray diffraction in the pulsed laser heated diamond anvil cell

    SciTech Connect

    Goncharov, Alexander F.; Prakapenka, Vitali B.; Struzhkin, Viktor V.; Kantor, Innokenty; Rivers, Mark L.; Dalton, D. Allen

    2010-11-19

    We have developed in situ x-ray synchrotron diffraction measurements of samples heated by a pulsed laser in the diamond anvil cell at pressure up to 60 GPa. We used an electronically modulated 2-10 kHz repetition rate, 1064-1075 nm fiber laser with 1-100 {micro}s pulse width synchronized with a gated x-ray detector (Pilatus) and time-resolved radiometric temperature measurements. This enables the time domain measurements as a function of temperature in a microsecond time scale (averaged over many events, typically more than 10,000). X-ray diffraction data, temperature measurements, and finite element calculations with realistic geometric and thermochemical parameters show that in the present experimental configuration, samples 4 {micro}m thick can be continuously temperature monitored (up to 3000 K in our experiments) with the same level of axial and radial temperature uniformities as with continuous heating. We find that this novel technique offers a new and convenient way of fine tuning the maximum sample temperature by changing the pulse width of the laser. This delicate control, which may also prevent chemical reactivity and diffusion, enables accurate measurement of melting curves, phase changes, and thermal equations of state.

  14. X-ray diffraction in the pulsed laser heated diamond anvil cell

    SciTech Connect

    Goncharov, Alexander F.; Struzhkin, Viktor V.; Dalton, D. Allen; Prakapenka, Vitali B.; Kantor, Innokenty; Rivers, Mark L.

    2010-11-15

    We have developed in situ x-ray synchrotron diffraction measurements of samples heated by a pulsed laser in the diamond anvil cell at pressure up to 60 GPa. We used an electronically modulated 2-10 kHz repetition rate, 1064-1075 nm fiber laser with 1-100 {mu}s pulse width synchronized with a gated x-ray detector (Pilatus) and time-resolved radiometric temperature measurements. This enables the time domain measurements as a function of temperature in a microsecond time scale (averaged over many events, typically more than 10 000). X-ray diffraction data, temperature measurements, and finite element calculations with realistic geometric and thermochemical parameters show that in the present experimental configuration, samples 4 {mu}m thick can be continuously temperature monitored (up to 3000 K in our experiments) with the same level of axial and radial temperature uniformities as with continuous heating. We find that this novel technique offers a new and convenient way of fine tuning the maximum sample temperature by changing the pulse width of the laser. This delicate control, which may also prevent chemical reactivity and diffusion, enables accurate measurement of melting curves, phase changes, and thermal equations of state.

  15. X-ray diffraction in the pulsed laser heated diamond anvil cell

    SciTech Connect

    Goncharov, Alexander F.; Prakapenka, Vitali B.; Struzhkin, Viktor V.; Kantor, Innokenty; Rivers, Mark L.; Dalton, D. Allen

    2010-11-03

    We have developed in situ x-ray synchrotron diffraction measurements of samples heated by a pulsed laser in the diamond anvil cell at pressure up to 60 GPa. We used an electronically modulated 2–10 kHz repetition rate, 1064–1075 nm fiber laser with 1–100 μs pulse width synchronized with a gated x-ray detector (Pilatus) and time-resolved radiometric temperature measurements. This enables the time domain measurements as a function of temperature in a microsecond time scale (averaged over many events, typically more than 10,000). X-ray diffraction data, temperature measurements, and finite element calculations with realistic geometric and thermochemical parameters show that in the present experimental configuration, samples 4 μm thick can be continuously temperature monitored (up to 3000 K in our experiments) with the same level of axial and radial temperature uniformities as with continuous heating. We find that this novel technique offers a new and convenient way of fine tuning the maximum sample temperature by changing the pulse width of the laser. This delicate control, which may also prevent chemical reactivity and diffusion, enables accurate measurement of melting curves, phase changes, and thermal equations of state.

  16. Ultrafast self-gating Bragg diffraction of exploding nanocrystals in an X-ray laser.

    PubMed

    Caleman, Carl; Tîmneanu, Nicuşor; Martin, Andrew V; Jönsson, H Olof; Aquila, Andrew; Barty, Anton; Scott, Howard A; White, Thomas A; Chapman, Henry N

    2015-01-26

    In structural determination of crystalline proteins using intense femtosecond X-ray lasers, damage processes lead to loss of structural coherence during the exposure. We use a nonthermal description for the damage dynamics to calculate the ultrafast ionization and the subsequent atomic displacement. These effects degrade the Bragg diffraction on femtosecond time scales and gate the ultrafast imaging. This process is intensity and resolution dependent. At high intensities the signal is gated by the ionization affecting low resolution information first. At lower intensities, atomic displacement dominates the loss of coherence affecting high-resolution information. We find that pulse length is not a limiting factor as long as there is a high enough X-ray flux to measure a diffracted signal.

  17. Nonlinear Raman-Nath diffraction of femtosecond laser pulses in a 2D nonlinear photonic crystal.

    PubMed

    Vyunishev, A M; Arkhipkin, V G; Slabko, V V; Baturin, I S; Akhmatkhanov, A R; Shur, V Ya; Chirkin, A S

    2015-09-01

    We study second-harmonic generation (SHG) of femtosecond laser pulses in a rectangular two-dimensional nonlinear photonic crystal (NLPC). Multiple SH beams were observed in the vicinity of the propagation direction of the fundamental beam. It has been verified that the angular positions of these beams obey the conditions of nonlinear Raman-Nath diffraction (NRND). The measured SH spectra of specific NRND orders consist of narrow peaks that experience a high-frequency spectral shift as the order grows. We derive an analytical expression for the process studied and find the theoretical results to be in good agreement with the experimental data. We estimate the enhancement factor of nonlinear Raman-Nath diffraction in 2D NLPC to be 70. PMID:26368697

  18. Ultrafast self-gating Bragg diffraction of exploding nanocrystals in an X-ray laser.

    PubMed

    Caleman, Carl; Tîmneanu, Nicuşor; Martin, Andrew V; Jönsson, H Olof; Aquila, Andrew; Barty, Anton; Scott, Howard A; White, Thomas A; Chapman, Henry N

    2015-01-26

    In structural determination of crystalline proteins using intense femtosecond X-ray lasers, damage processes lead to loss of structural coherence during the exposure. We use a nonthermal description for the damage dynamics to calculate the ultrafast ionization and the subsequent atomic displacement. These effects degrade the Bragg diffraction on femtosecond time scales and gate the ultrafast imaging. This process is intensity and resolution dependent. At high intensities the signal is gated by the ionization affecting low resolution information first. At lower intensities, atomic displacement dominates the loss of coherence affecting high-resolution information. We find that pulse length is not a limiting factor as long as there is a high enough X-ray flux to measure a diffracted signal. PMID:25835880

  19. Ultrafast laser parallel microdrilling using multiple annular beams generated by a spatial light modulator

    NASA Astrophysics Data System (ADS)

    Kuang, Zheng; Perrie, Walter; Edwardson, Stuart P.; Fearon, Eamonn; Dearden, Geoff

    2014-03-01

    Ultrafast laser parallel microdrilling using diffractive multiple annular beam patterns is demonstrated in this paper. The annular beam was generated by diffractive axicon computer generated holograms (CGHs) using a spatial light modulator. The diameter of the annular beam can be easily adjusted by varying the radius of the smallest ring in the axicon. Multiple annular beams with arbitrary arrangement and multiple annular beam arrays were generated by superimposing an axicon CGH onto a grating and lenses algorithm calculated multi-beam CGH and a binary Dammann grating CGH, respectively. Microholes were drilled through a 0.03 mm thick stainless steel foil using the multiple annular beams. By avoiding huge laser output attenuation and mechanical annular scanning, the processing is ˜200 times faster than the normal single beam processing.

  20. Time-Domain X-ray Diffraction in the Pulsed Laser Heated Diamond Anvil Cell

    NASA Astrophysics Data System (ADS)

    Prakapenka, V.; Goncharov, A. F.; Struzhkin, V.; Kantor, I.; Rivers, M. L.; Dalton, D. A.

    2011-12-01

    We have developed in situ x-ray synchrotron diffraction measurements of samples heated by a pulsed laser in the diamond anvil cell (DAC) at pressure up to 100 GPa and 3500 K. We used an electronically modulated 2-10 kHz repetition rate, 1064-1075 nm fiber laser with 1-100 microseconds pulse width synchronized with a gated x-ray detector (Pilatus) and time resolved radiometric temperature measurements. For the special APS hybrid mode, the measurements were also synchronized with a 500 ns long bunch carrying 88% of the ring current. This setup enables time domain measurements as a function of temperature in a micrometers time scale (averaged over many events, typically more than 10,000). X-ray diffraction data, temperature measurements, and finite element calculations with realistic geometric and thermochemical parameters show that in the present experimental configuration samples 4 micrometers thick can be continuously temperature monitored (up to 3000 K in our experiments) with the same level of axial and radial temperature uniformity as with continuous heating. We find that this novel technique offers a new and convenient way of fine tuning the maximum sample temperature by changing the pulse width of the laser. We will show examples of studies of the melting, thermal equation of state, and chemical reactivity. We acknowledge support from NSF EAR-0842057, DOE/ NNSA (CDAC), and EFree, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award No. DESC0001057. X-ray diffraction measurements were performed at GSECARS (APS) supported by DOE Contract No.W-31-109- Eng-38.

  1. Laser-induced effects in carbon suspensions and diffraction by volume gratings in liquids

    NASA Astrophysics Data System (ADS)

    Chen, Huxiong

    1997-12-01

    Two projects are covered in this thesis. The first project is an investigation of acoustic and chemical effects generated by high power laser pulses in carbon suspensions. Carbon particles absorb energy from the laser pulses and are heated to a few thousand degrees C. The high temperatures initiate reactions between carbon and the surrounding water generating permanent gases. Hydrogen, carbon monoxide, carbon dioxide, and several hydrocarbons have been identified as product gases. With respect to sound wave generation the change in volume of the material owing to thermal and chemical expansion is discussed. A thermodynamic theory governing the generation of the photoacoustic waves from these two mechanism is developed. A comparison between photoacoustic effects caused mainly by the chemical mechanism and those generated by the thermal mechanism is given. The chemical mechanism gives an acoustic signal 2,000 times greater in magnitude than would be generated by purely thermal mechanism (normalized to absorption coefficient). Structural changes of the carbon particle are reported. The originally solid particles first become large hollow particles and then disappear according to electron microscopy. The second project deals with diffraction by volume gratings. A rigorous theory governing non-attentuated planar volume gratings developed by Gaylord and Moharam is utilized. A generalized theory incorporating attentuation along the depth for planar volume gratings with TE incident probe beams is developed. Experiments have been carried out to investigate the diffraction of volume gratings generated by two coherent nanosecond laser pulses in methanol. The magnitude of the change in index of refraction is extracted. Criteria for delineation of different diffraction regimes are discussed. Approximate solutions to the first order coupled-wave equations are given substantiating the criteria.

  2. Modeling focusing characteristics of low Fnumber diffractive optical elements with continuous relief fabricated by laser direct writing.

    PubMed

    Shan, Mingguang; Tan, Jiubin

    2007-12-10

    A theoretical model is established using Rayleigh-Sommerfeld diffraction theory to describe the diffraction focusing characteristics of low F-number diffractive optical elements with continuous relief fabricated by laser direct writing, and continuous-relief diffractive optical elements with a design wavelength of 441.6nm and a F-number of F/4 are fabricated and measured to verify the validity of the diffraction focusing model. The measurements made indicate that the spot size is 1.75mum and the diffraction efficiency is 70.7% at the design wavelength, which coincide well with the theoretical results: a spot size of 1.66mum and a diffraction efficiency of 71.2%.

  3. Visible light surface emitting semiconductor laser

    DOEpatents

    Olbright, Gregory R.; Jewell, Jack L.

    1993-01-01

    A vertical-cavity surface-emitting laser is disclosed comprising a laser cavity sandwiched between two distributed Bragg reflectors. The laser cavity comprises a pair of spacer layers surrounding one or more active, optically emitting quantum-well layers having a bandgap in the visible which serve as the active optically emitting material of the device. The thickness of the laser cavity is m .lambda./2n.sub.eff where m is an integer, .lambda. is the free-space wavelength of the laser radiation and n.sub.eff is the effective index of refraction of the cavity. Electrical pumping of the laser is achieved by heavily doping the bottom mirror and substrate to one conductivity-type and heavily doping regions of the upper mirror with the opposite conductivity type to form a diode structure and applying a suitable voltage to the diode structure. Specific embodiments of the invention for generating red, green, and blue radiation are described.

  4. Diffusion filter eliminates fringe effects of coherent laser light source

    NASA Technical Reports Server (NTRS)

    Olsasky, M. J.

    1970-01-01

    Diffusion filter comprised of small particles in colloidal suspension reduces the coherence of a laser beam used as a photographic light source. Interference patterns which obscure details in photographic film are eliminated, the intensity and collimation are moderately affected.

  5. Development of a Compact Optical-MEMS Scanner with Integrated VCSEL Light Source and Diffractive Optics

    SciTech Connect

    Krygowski, Thomas W.; Reyes, David; Rodgers, M. Steven; Smith, James H.; Warren, Mial; Sweatt, William; Blum-Spahn, Olga; Wendt, Joel R.; Asbill, Randy

    1999-06-30

    In this work the design and initial fabrication results are reported for the components of a compact optical-MEMS laser scanning system. This system integrates a silicon MEMS laser scanner, a Vertical Cavity Surface Emitting Laser (VCSEL) and passive optical components. The MEMS scanner and VCSEL are mounted onto a fused silica substrate which serves as an optical interconnect between the devices. Two Diffractive Optical Elements (DOEs) are etched into the fused silica substrate to focus the VCSEL beam and increase the scan range. The silicon MEMS scanner consists of an actuator that continuously scans the position of a large polysilicon gold-coated shuttle containing a third DOE. Interferometric measurements show that the residual stress in the 500 {micro}m x 1000 {micro}m shuttle is extremely low, with a maximum deflection of only 0.18{micro}m over an 800 {micro}m span for an unmetallized case and a deflection of 0.56{micro}m for the metallized case. A conservative estimate for the scan range is {approximately}{+-}4{degree}, with a spot size of about 0.5 mm, producing 50 resolvable spots. The basic system architecture, optical and MEMS design is reported in this paper, with an emphasis on the design and fabrication of the silicon MEMS scanner portion of the system.

  6. Fraunhofer diffraction of atomic matter waves: electron transfer studies with a laser cooled target.

    PubMed

    van der Poel, M; Nielsen, C V; Gearba, M A; Andersen, N

    2001-09-17

    We have constructed an apparatus combining the experimental techniques of cold target recoil ion momentum spectroscopy and a laser cooled target. We measure angle differential cross sections in Li(+)+Na-->Li+Na(+) electron transfer collisions in the keV energy regime with a momentum resolution of 0.12 a.u. yielding an order of magnitude better angular resolution than previous measurements. We resolve Fraunhofer-type diffraction patterns in the differential cross sections. Good agreement with predictions of the semiclassical impact parameter method is obtained.

  7. Efficient generation of 509 nm light by sum-frequency mixing between two tapered diode lasers

    NASA Astrophysics Data System (ADS)

    Tawfieq, Mahmoud; Jensen, Ole Bjarlin; Hansen, Anders Kragh; Sumpf, Bernd; Paschke, Katrin; Andersen, Peter E.

    2015-03-01

    We demonstrate a concept for visible laser sources based on sum-frequency generation of beam combined tapered diode lasers. In this specific case, a 1.7 W sum-frequency generated green laser at 509 nm is obtained, by frequency adding of 6.17 W from a 978 nm tapered diode laser with 8.06 W from a 1063 nm tapered diode laser, inside a periodically poled MgO doped lithium niobate crystal. This corresponds to an optical to optical conversion efficiency of 12.1%. As an example of potential applications, the generated nearly diffraction-limited green light is used for pumping a Ti:sapphire laser, thus demonstrating good beam quality and power stability. The maximum output powers achieved when pumping the Ti:sapphire laser are 226 mW (CW) and 185 mW (mode-locked) at 1.7 W green pump power. The optical spectrum emitted by the mode-locked Ti:sapphire laser shows a spectral width of about 54 nm (FWHM), indicating less than 20 fs pulse width.

  8. Near-field surface plasmon effects on Au-double-slit diffraction for polychromatic light

    PubMed Central

    2014-01-01

    The surface plasmon effects on near-field diffraction for polychromatic light are studied. An Au-double-slit is used as the model and Fresnel integral is employed to perform the theoretic analysis. The results are illustrated with numerical examples and they show that, compared with the normal double-slit, the plasmon effect changes the spectral shift from redshift to blueshift and also enhances the intensity peak. This effect can be used in optical data transmission or specific spectral selectors. PMID:25386100

  9. An improved light source for laser ranging

    NASA Technical Reports Server (NTRS)

    Hamal, Karel; Richardson, Martin

    1993-01-01

    The development of a new laser material, Cr-doped LiSAF, makes possible the development of a laser source for satellite ranging systems that is more superior in performance capabilities than current Nd:YAG-based laser sources. This new material offers the potential of shorter pulses and more preferable wavelengths (850 and 425 nm) than multiwavelength Nd:YAG systems, leading to superior ranging resolution and greater detection sensitivity. We are embarking on a feasibility study of a two-wavelength, mode-locked laser system based on Cr:LiSAF, providing shorter pulses for improved ranging resolution.

  10. Fluorescent photography of spray droplets using a laser light source

    NASA Technical Reports Server (NTRS)

    Groeneweg, J.; Hiroyasu, H.; Sowls, R.

    1969-01-01

    Monochromatic laser emission transformed by a fluorescent process into droplet emission over a wavelength band provides high light intensities for obtaining adequate time resolution to stop droplet motion in photographic spray studies. Experiments showed that the Q-switched laser-optical harmonic generator combination produced sharp, well-exposed droplet images.

  11. Imaging an aligned polyatomic molecule with laser-induced electron diffraction

    PubMed Central

    Pullen, Michael G.; Wolter, Benjamin; Le, Anh-Thu; Baudisch, Matthias; Hemmer, Michaël; Senftleben, Arne; Schröter, Claus Dieter; Ullrich, Joachim; Moshammer, Robert; Lin, C. D.; Biegert, Jens

    2015-01-01

    Laser-induced electron diffraction is an evolving tabletop method that aims to image ultrafast structural changes in gas-phase polyatomic molecules with sub-Ångström spatial and femtosecond temporal resolutions. Here we demonstrate the retrieval of multiple bond lengths from a polyatomic molecule by simultaneously measuring the C–C and C–H bond lengths in aligned acetylene. Our approach takes the method beyond the hitherto achieved imaging of simple diatomic molecules and is based on the combination of a 160 kHz mid-infrared few-cycle laser source with full three-dimensional electron–ion coincidence detection. Our technique provides an accessible and robust route towards imaging ultrafast processes in complex gas-phase molecules with atto- to femto-second temporal resolution. PMID:26105804

  12. Nanosecond laser pulse heating of a platinum surface studied by pump-probe X-ray diffraction

    NASA Astrophysics Data System (ADS)

    Shayduk, Roman; Vonk, Vedran; Arndt, Björn; Franz, Dirk; Strempfer, Jörg; Francoual, Sonia; Keller, Thomas F.; Spitzbart, Tobias; Stierle, Andreas

    2016-07-01

    We report on the quantitative determination of the transient surface temperature of Pt(110) upon nanosecond laser pulse heating. We find excellent agreement between heat transport theory and the experimentally determined transient surface temperature as obtained from time-resolved X-ray diffraction on timescales from hundred nanoseconds to milliseconds. Exact knowledge of the surface temperature's temporal evolution after laser excitation is crucial for future pump-probe experiments at synchrotron storage rings and X-ray free electron lasers.

  13. Compact diffraction grating laser wavemeter with sub-picometer accuracy and picowatt sensitivity using a webcam imaging sensor.

    PubMed

    White, James D; Scholten, Robert E

    2012-11-01

    We describe a compact laser wavelength measuring instrument based on a small diffraction grating and a consumer-grade webcam. With just 1 pW of optical power, the instrument achieves absolute accuracy of 0.7 pm, sufficient to resolve individual hyperfine transitions of the rubidium absorption spectrum. Unlike interferometric wavemeters, the instrument clearly reveals multimode laser operation, making it particularly suitable for use with external cavity diode lasers and atom cooling and trapping experiments. PMID:23206048

  14. Compact diffraction grating laser wavemeter with sub-picometer accuracy and picowatt sensitivity using a webcam imaging sensor

    NASA Astrophysics Data System (ADS)

    White, James D.; Scholten, Robert E.

    2012-11-01

    We describe a compact laser wavelength measuring instrument based on a small diffraction grating and a consumer-grade webcam. With just 1 pW of optical power, the instrument achieves absolute accuracy of 0.7 pm, sufficient to resolve individual hyperfine transitions of the rubidium absorption spectrum. Unlike interferometric wavemeters, the instrument clearly reveals multimode laser operation, making it particularly suitable for use with external cavity diode lasers and atom cooling and trapping experiments.

  15. Laser Light: Using Laser Refractometry to Determine Concentration.

    ERIC Educational Resources Information Center

    Gauger, Robert

    1995-01-01

    Laser refractometry is a science-technology-based activity that requires students to manipulate a variety of equipment, tools, materials, and critical-thinking skills. Students use a laser to measure the percent of glucose in a solution by calibrating the system, taking measurements, and computing the concentration. (MKR)

  16. Gold nanoparticle-polydimethylsiloxane films reflect light internally by optical diffraction and Mie scattering

    NASA Astrophysics Data System (ADS)

    Dunklin, Jeremy R.; Forcherio, Gregory T.; Roper, D. Keith

    2015-08-01

    Optical properties of polymer films embedded with plasmonic nanoparticles (NPs) are important in many implementations. In this work, optical extinction by polydimethylsiloxane (PDMS) films containing gold (Au) NPs was enhanced at resonance compared to AuNPs in suspensions, Beer-Lambert law, or Mie theory by internal reflection due to optical diffraction in 16 nm AuNP-PDMS films and Mie scattering in 76 nm AuNP-PDMS films. Resonant extinction per AuNP for 16 nm AuNPs with negligible resonant Mie scattering was enhanced up to 1.5-fold at interparticle separation (i.e., Wigner-Seitz radii) comparable to incident wavelength. It was attributable to diffraction through apertures formed by overlapping electric fields of adjacent, resonantly excited AuNPs at Wigner-Seitz radii equal to or less than incident wavelengths. Resonant extinction per AuNP for strongly Mie scattering 76 nm AuNPs was enhanced up to 1.3-fold at Wigner-Seitz radii four or more times greater than incident wavelength. Enhanced light trapping from diffraction and/or scattering is relevant to optoelectronic, biomedical, and catalytic activity of substrates embedded with NPs.

  17. Control of light backscattering in blood during intravenous laser irradiation

    NASA Astrophysics Data System (ADS)

    Melnik, Ivan S.; Popov, V. D.; Rusina, Tatyana V.; Dets, Sergiy M.

    1997-02-01

    One of the most important problems in modern laser medicine is the determination of system response on laser treatment. Reaction of living system is significant during many kinds of laser procedures like surgery, therapy and biostimulation. Our study was aimed to optimize laser exposure using feed-back fiber system for intravenous laser irradiation of blood (ILIB). This system consisted of helium-neon laser (633 nm, 5 mW) with coupled fiber unit, photodetector and PC interface. Photodetector signals produced due to light backscattering were storaged and processed during all blood irradiation procedure. Significant time-dependent variations were observed within 9-15 min after beginning of treatment procedure and were correlated with number of trials, stage and character of disease. The designed feed-back system allows us to register a human blood response on laser irradiation to achieve better cure effect.

  18. Scattering of a Young’s diffractive electromagnetic light wave by quasi-homogeneous medium

    NASA Astrophysics Data System (ADS)

    Li, Jia; Wu, Pinghui; Chang, Liping; Wu, Zhefu

    2015-09-01

    While remaining accurate under the first-order Born approximation and the paraxial assumption, the scattering of a Young’s diffractive electromagnetic light wave by a quasi-homogeneous (QH) medium is specifically addressed in this study. Analytical expressions are derived for spectral density as well as the spectral degree of coherence of the scattered field. As long as the components of the complex amplitude of incident waves are proportional to each other, the resultant scattered light in the far field is proven to satisfy two reciprocity relations, namely, that the spectral density is proportional to the spatial Fourier transformation of the normalized correlation coefficient of the scattering potential, while the spectral degree of coherence is dependent only on the spatial Fourier transformation of the strength of the scattering potential.

  19. Biomodulation of light on cells in laser surgery

    NASA Astrophysics Data System (ADS)

    Liu, Timon C.; Li, Yan; Duan, Rui; Cai, Xiongwei

    2002-04-01

    In laser surgery, it has been observed pulsed 532-nm laser can avoid postoperative purpura, but pulsed 585-nm, 595-nm or 600-nm lasers nonetheless cause purpura when they were used to treat port-wine stains; the XeCl excimer laser (308 nm) can safely and effectively clear psoriasis; both XeCl excimer laser and Ho:YAG laser were used in coronary interventions, but only former was approved by the FDA; open channels after ultraviolet (UV) laser treatment and closed channels with infrared (IR) lasers for transmyocardial laser revascularization; and so on. In this paper, the biological information model of low intensity laser (BIML) is extended to include UVA biomodulation and is used to understand these phenomena. Although the central intensity of the laser beam is so intense that it destroys the tissue, the edge intensity is so low that it can induce biomodulation. Our investigation showed that biomodulation of light on cells might play an important role in the long-term effects of laser surgery.

  20. Spin-to-orbit conversion at acousto-optic diffraction of light: conservation of optical angular momentum.

    PubMed

    Skab, Ihor; Vlokh, Rostyslav

    2012-04-01

    Acousto-optic diffraction of light in optically active cubic crystals is analyzed from the viewpoint of conservation of optical angular momentum. It is shown that the availability of angular momentum in the diffracted optical beam can be necessarily inferred from the requirements of angular momentum conservation law. As follows from our analysis, a circularly polarized diffracted wave should bear an orbital angular momentum. The efficiency of the spin-to-orbit momentum conversion is governed by the efficiency of acousto-optic diffraction.

  1. Combined resistive and laser heating technique for in situ radial X-ray diffraction in the diamond anvil cell at high pressure and temperature.

    PubMed

    Miyagi, Lowell; Kanitpanyacharoen, Waruntorn; Raju, Selva Vennila; Kaercher, Pamela; Knight, Jason; MacDowell, Alastair; Wenk, Hans-Rudolf; Williams, Quentin; Alarcon, Eloisa Zepeda

    2013-02-01

    To extend the range of high-temperature, high-pressure studies within the diamond anvil cell, a Liermann-type diamond anvil cell with radial diffraction geometry (rDAC) was redesigned and developed for synchrotron X-ray diffraction experiments at beamline 12.2.2 of the Advanced Light Source. The rDAC, equipped with graphite heating arrays, allows simultaneous resistive and laser heating while the material is subjected to high pressure. The goals are both to extend the temperature range of external (resistive) heating and to produce environments with lower temperature gradients in a simultaneously resistive- and laser-heated rDAC. Three different geomaterials were used as pilot samples to calibrate and optimize conditions for combined resistive and laser heating. For example, in Run#1, FeO was loaded in a boron-mica gasket and compressed to 11 GPa then gradually resistively heated to 1007 K (1073 K at the diamond side). The laser heating was further applied to FeO to raise temperature to 2273 K. In Run#2, Fe-Ni alloy was compressed to 18 GPa and resistively heated to 1785 K (1973 K at the diamond side). The combined resistive and laser heating was successfully performed again on (Mg0.9Fe0.1)O in Run#3. In this instance, the sample was loaded in a boron-kapton gasket, compressed to 29 GPa, resistive-heated up to 1007 K (1073 K at the diamond side), and further simultaneously laser-heated to achieve a temperature in excess of 2273 K at the sample position. Diffraction patterns obtained from the experiments were deconvoluted using the Rietveld method and quantified for lattice preferred orientation of each material under extreme conditions and during phase transformation.

  2. Combined resistive and laser heating technique for in situ radial X-ray diffraction in the diamond anvil cell at high pressure and temperature

    SciTech Connect

    Miyagi, Lowell; Kanitpanyacharoen, Waruntorn; Kaercher, Pamela; Wenk, Hans-Rudolf; Alarcon, Eloisa Zepeda; Raju, Selva Vennila; Knight, Jason; MacDowell, Alastair; Williams, Quentin

    2013-02-15

    To extend the range of high-temperature, high-pressure studies within the diamond anvil cell, a Liermann-type diamond anvil cell with radial diffraction geometry (rDAC) was redesigned and developed for synchrotron X-ray diffraction experiments at beamline 12.2.2 of the Advanced Light Source. The rDAC, equipped with graphite heating arrays, allows simultaneous resistive and laser heating while the material is subjected to high pressure. The goals are both to extend the temperature range of external (resistive) heating and to produce environments with lower temperature gradients in a simultaneously resistive- and laser-heated rDAC. Three different geomaterials were used as pilot samples to calibrate and optimize conditions for combined resistive and laser heating. For example, in Run1, FeO was loaded in a boron-mica gasket and compressed to 11 GPa then gradually resistively heated to 1007 K (1073 K at the diamond side). The laser heating was further applied to FeO to raise temperature to 2273 K. In Run2, Fe-Ni alloy was compressed to 18 GPa and resistively heated to 1785 K (1973 K at the diamond side). The combined resistive and laser heating was successfully performed again on (Mg{sub 0.9}Fe{sub 0.1})O in Run3. In this instance, the sample was loaded in a boron-kapton gasket, compressed to 29 GPa, resistive-heated up to 1007 K (1073 K at the diamond side), and further simultaneously laser-heated to achieve a temperature in excess of 2273 K at the sample position. Diffraction patterns obtained from the experiments were deconvoluted using the Rietveld method and quantified for lattice preferred orientation of each material under extreme conditions and during phase transformation.

  3. Toward efficient light diffraction and intensity variations by using wide bandwidth surface acoustic wave

    NASA Astrophysics Data System (ADS)

    Lee, Young Ok; Chen, Fu; Lee, Kee Keun

    2016-06-01

    We have developed acoustic-optic (AO) based display units for implementing a handheld hologram display by modulating light deflection through wide bandwidth surface acoustic wave (SAW). The developed AO device consists of a metal layer, a ZnS waveguide layer, SAW inter digital transducers (IDTs), and a screen for display. When RF power with a particular resonant frequency was applied to IDTs, SAW was radiated and interfered with confined beam propagating along ZnS waveguide layer. The AO interacted beam was deflected laterally toward a certain direction depending on Bragg diffraction condition, exited out of the waveguide layer and then directed to the viewing screen placed at a certain distance from the device to form a single pixel. The deflected angles was adjusted by modulating the center frequency of the SAW IDT (SAW grating), the RF power of SAW, and the angles between propagating light beam path along waveguide and radiating SAW. The diffraction efficiency was also characterized in terms of waveguide thickness, SAW RF input power, and aperture length. Coupling of mode (COM) modeling was fulfilled to find optimal device parameters prior to fabrication. All the parameters affecting the deflection angle and efficiency to form a pixel for a three-dimensional (3D) hologram image were characterized and then discussed.

  4. Quantum-mechanical diffraction theory of light from a small hole: Extinction-theorem approach

    NASA Astrophysics Data System (ADS)

    Jung, Jesper; Keller, Ole

    2015-07-01

    In a recent paper [Phys. Rev. A 90, 043830 (2014), 10.1103/PhysRevA.90.043830] it was shown that the so-called aperture response tensor is the central concept in the microscopic quantum theory of light diffraction from a small hole in a flat screen. It was further shown that the quantum mechanical theory of diffraction only requires a preknowledge of the incident field plus the electronic properties of identical screens with and without a hole. Starting from the quantum mechanical expression for the linear conductivity tensor, we study the related causal conductivity tensor paying particular attention to diamagnetic electron dynamics. Using a nonlocal-potential separation assumption, we present a calculation of the diamagnetic causal surface conductivity for a jellium quantum-well screen using a two-dimensional Hartree-Fock model. In the diamagnetic case the difference between the light-unperturbed electron densities for screens with (n0) and without (n∞0) holes are the primary quantities for the diffraction theory. In a central part (Sec. IV) of this article we determine n0 via a quantum-mechanical two-dimensional extinction-theorem approach related to elastic electron scattering from a hole with an electronic selvedge. For heuristic purposes we illustrate aspects of the extinction-theorem theory by applying the approach for an infinitely high potential barrier to the vacuum hole. Finally, we calculate and discuss the aperture response tensor in the small hole limit and in the zeroth-order Born approximation. Our final result for the aperture response tensor establishes the bridge to the anisotropic electric dipole polarizability tensor of the hole. It turns out that the effective optical aperture (hole) size relates closely to the extension of the relevant electronic wave functions scattered from the hole.

  5. Stress-induced rigidification of erythrocytes as determined by laser diffraction and image analysis

    NASA Astrophysics Data System (ADS)

    Wolf, Guido; Bayer, Rainer; Ostuni, Dieter

    1992-07-01

    An apparatus to measure red cell deformability, the laser diffractoscope, is presented. As in ektacytometry, the apparatus generates diffraction patterns using a laser beam that passes through a red blood cell (RBC) suspension in a viscometer. Introducing a CCD camera to record the diffraction pattern and computer-aided image analysis has reduce the measurement error to below 1% (variation coefficient). Employing this apparatus we have studied the effects of mechanical stress on RBC deformability in vitro. We submitted the erythrocytes to different shear stresses of various magnitudes (260 to 2620/s, viscosity of suspending medium 24 cP) and variable duration 1 to 16 min). We demonstrate that a high mechanical stress reduces deformability at low shear rates but does not influence elongation at high shear rates and that the rigidification is related to mechanical stress in a dose-dependent manner. The period of exposure as well as the degree of mechanical stress influences the extent of deformability loss. We also show that RBC rigidification accumulates if mechanical stress is applied repetitively, the cells could not recover from this stress, below a certain threshold (1100/s, 24 cP) shearing does not produce any loss of flexibility, and the decrease of deformability is not accompanied with detectable hemolysis. It is suggested that the shear- induced rigidification is due to rearrangements in the cytoskeleton of the erythrocyte.

  6. The effects of slipage and diffraction in long wavelength operation of a free electron laser

    SciTech Connect

    Zhulin, V.I.; Haselhoff, E.H.; Amersfoort, P.W. van

    1995-01-01

    The Free-Electron Laser user facility FELIX produces picosecond optical pulses in the wavelength range of 5-110 {mu}m. The proposed installation of a new undulator with a larger magnetic period would allow extension towards considerably larger wavelengths. This would result in the production of extremely short, far-infrared pulses, with a duration of a single optical period or even less. In order to investigate the pulse propagation for free-electron lasers operating in the long wavelength limit, a three-dimensional simulation code was developed. Using the FELIX parameters, with the addition of a long-period undulator, the effects of slippage, diffraction losses, changes in the filling factor, as well as the effects of the optical cavity geometry were studied for wavelengths up to 300 {mu}m, with electron pulses in the ps regime. It is shown that slippage effects are less restrictive for long wavelength operation than the increasing losses due to optical beam diffraction.

  7. Optical laser systems at the Linac Coherent Light Source

    DOE PAGESBeta

    Minitti, Michael P.; Robinson, Joseph S.; Coffee, Ryan N.; Edstrom, Steve; Gilevich, Sasha; Glownia, James M.; Granados, Eduardo; Hering, Philippe; Hoffmann, Matthias C.; Miahnahri, Alan; et al

    2015-04-22

    Ultrafast optical lasers play an essential role in exploiting the unique capabilities of recently commissioned X-ray free-electron laser facilities such as the Linac Coherent Light Source (LCLS). Pump–probe experimental techniques reveal ultrafast dynamics in atomic and molecular processes and reveal new insights in chemistry, biology, material science and high-energy-density physics. This manuscript describes the laser systems and experimental methods that enable cutting-edge optical laser/X-ray pump–probe experiments to be performed at LCLS.

  8. Optical laser systems at the Linac Coherent Light Source

    PubMed Central

    Minitti, Michael P.; Robinson, Joseph S.; Coffee, Ryan N.; Edstrom, Steve; Gilevich, Sasha; Glownia, James M.; Granados, Eduardo; Hering, Philippe; Hoffmann, Matthias C.; Miahnahri, Alan; Milathianaki, Despina; Polzin, Wayne; Ratner, Daniel; Tavella, Franz; Vetter, Sharon; Welch, Marc; White, William E.; Fry, Alan R.

    2015-01-01

    Ultrafast optical lasers play an essential role in exploiting the unique capabilities of recently commissioned X-ray free-electron laser facilities such as the Linac Coherent Light Source (LCLS). Pump–probe experimental techniques reveal ultrafast dynamics in atomic and molecular processes and reveal new insights in chemistry, biology, material science and high-energy-density physics. This manuscript describes the laser systems and experimental methods that enable cutting-edge optical laser/X-ray pump–probe experiments to be performed at LCLS. PMID:25931064

  9. Optical laser systems at the Linac Coherent Light Source.

    PubMed

    Minitti, Michael P; Robinson, Joseph S; Coffee, Ryan N; Edstrom, Steve; Gilevich, Sasha; Glownia, James M; Granados, Eduardo; Hering, Philippe; Hoffmann, Matthias C; Miahnahri, Alan; Milathianaki, Despina; Polzin, Wayne; Ratner, Daniel; Tavella, Franz; Vetter, Sharon; Welch, Marc; White, William E; Fry, Alan R

    2015-05-01

    Ultrafast optical lasers play an essential role in exploiting the unique capabilities of recently commissioned X-ray free-electron laser facilities such as the Linac Coherent Light Source (LCLS). Pump-probe experimental techniques reveal ultrafast dynamics in atomic and molecular processes and reveal new insights in chemistry, biology, material science and high-energy-density physics. This manuscript describes the laser systems and experimental methods that enable cutting-edge optical laser/X-ray pump-probe experiments to be performed at LCLS.

  10. X-ray laser-induced electron dynamics observed by femtosecond diffraction from nanocrystals of Buckminsterfullerene.

    PubMed

    Abbey, Brian; Dilanian, Ruben A; Darmanin, Connie; Ryan, Rebecca A; Putkunz, Corey T; Martin, Andrew V; Wood, David; Streltsov, Victor; Jones, Michael W M; Gaffney, Naylyn; Hofmann, Felix; Williams, Garth J; Boutet, Sébastien; Messerschmidt, Marc; Seibert, M Marvin; Williams, Sophie; Curwood, Evan; Balaur, Eugeniu; Peele, Andrew G; Nugent, Keith A; Quiney, Harry M

    2016-09-01

    X-ray free-electron lasers (XFELs) deliver x-ray pulses with a coherent flux that is approximately eight orders of magnitude greater than that available from a modern third-generation synchrotron source. The power density of an XFEL pulse may be so high that it can modify the electronic properties of a sample on a femtosecond time scale. Exploration of the interaction of intense coherent x-ray pulses and matter is both of intrinsic scientific interest and of critical importance to the interpretation of experiments that probe the structures of materials using high-brightness femtosecond XFEL pulses. We report observations of the diffraction of extremely intense 32-fs nanofocused x-ray pulses by a powder sample of crystalline C60. We find that the diffraction pattern at the highest available incident power significantly differs from the one obtained using either third-generation synchrotron sources or XFEL sources operating at low output power and does not correspond to the diffraction pattern expected from any known phase of crystalline C60. We interpret these data as evidence of a long-range, coherent dynamic electronic distortion that is driven by the interaction of the periodic array of C60 molecular targets with intense x-ray pulses of femtosecond duration.

  11. X-ray laser-induced electron dynamics observed by femtosecond diffraction from nanocrystals of Buckminsterfullerene.

    PubMed

    Abbey, Brian; Dilanian, Ruben A; Darmanin, Connie; Ryan, Rebecca A; Putkunz, Corey T; Martin, Andrew V; Wood, David; Streltsov, Victor; Jones, Michael W M; Gaffney, Naylyn; Hofmann, Felix; Williams, Garth J; Boutet, Sébastien; Messerschmidt, Marc; Seibert, M Marvin; Williams, Sophie; Curwood, Evan; Balaur, Eugeniu; Peele, Andrew G; Nugent, Keith A; Quiney, Harry M

    2016-09-01

    X-ray free-electron lasers (XFELs) deliver x-ray pulses with a coherent flux that is approximately eight orders of magnitude greater than that available from a modern third-generation synchrotron source. The power density of an XFEL pulse may be so high that it can modify the electronic properties of a sample on a femtosecond time scale. Exploration of the interaction of intense coherent x-ray pulses and matter is both of intrinsic scientific interest and of critical importance to the interpretation of experiments that probe the structures of materials using high-brightness femtosecond XFEL pulses. We report observations of the diffraction of extremely intense 32-fs nanofocused x-ray pulses by a powder sample of crystalline C60. We find that the diffraction pattern at the highest available incident power significantly differs from the one obtained using either third-generation synchrotron sources or XFEL sources operating at low output power and does not correspond to the diffraction pattern expected from any known phase of crystalline C60. We interpret these data as evidence of a long-range, coherent dynamic electronic distortion that is driven by the interaction of the periodic array of C60 molecular targets with intense x-ray pulses of femtosecond duration. PMID:27626076

  12. Picosecond X-Ray Diffraction from Laser-Shocked Copper and Iron

    SciTech Connect

    Wark, J. S.; Hawreliak, J.; Higginbotham, A.; Rosolankova, K.; Sheppard, J.; Belak, J. F.; Collins, G. W.; Colvin, J. D.; Duchaineau, M.; Eggert, J. H.; Kalantar, D. H.; Lorenzana, H. E.; Remington, B. A.; Rudd, R. E.; Stolken, J. S.; Davies, H. M.; Germann, T. C.; Holian, B. L.; Kadau, K.; Lomdahl, P. S.

    2006-07-28

    In situ X-ray diffraction allows the determination of the structure of transient states of matter. We have used laser-plasma generated X-rays to study how single crystals of metals (copper and iron) react to uniaxial shock compression. We find that copper, as a face-centred-cubic material, allows rapid generation and motion of dislocations, allowing close to hydrostatic conditions to be achieved on sub-nanosecond timescales. Detailed molecular dynamics calculations provide novel information about the process, and point towards methods whereby the dislocation density might be measured during the passage of the shock wave itself. We also report on recent experiments where we have obtained diffraction images from shock-compressed single-crystal iron. The single crystal sample transforms to the hcp phase above a critical pressure, below which it appears to be uniaxially compressed bcc, with no evidence of plasticity. Above the transition threshold, clear evidence for the hcp phase can be seen in the diffraction images, and via a mechanism that is also consistent with recent multi- million atom molecular dynamics simulations that use the Voter- Chen potential. We believe these data to be of import, in that they constitute the first conclusive in situ evidence of the transformed structure of iron during the passage of a shock wave.

  13. Femtosecond Diffractive Imaging with a Soft-X-Ray Free-Electron Laser

    SciTech Connect

    Chapman, Henry N.; Barty, Anton: AUTHOR = Bogan, Michael J.; Boutet, Sebastian; Frank, Matthias; Hau-Riege, Stefan P.; Marchesini, Stefano; Woods, Bruce W.; Bajt, Sasa; Benner, W.Henry; London, Richard A.; Plonjes, Elke; Kuhlmann, Marion; Treusch, Rolf; Dusterer, Stefan; Tschentscher, Thomas; Schneider, Jochen R.; Spiller, Eberhard; Moller, Thomas; Bostedt, Christoph; Hoener, Matthias; Shapiro, David A.; /UC, Davis /SLAC /Uppsala U. /LLNL, Livermore /Uppsala U. /Uppsala U. /SLAC /Uppsala U.

    2010-10-07

    Theory predicts that with an ultrashort and extremely bright coherent X-ray pulse, a single diffraction pattern may be recorded from a large macromolecule, a virus, or a cell before the sample explodes and turns into a plasma. Here we report the first experimental demonstration of this principle using the FLASH soft X-ray free-electron laser. An intense 25 fs, 4 x 10{sup 13} W/cm{sup 2} pulse, containing 10{sup 12} photons at 32 nm wavelength, produced a coherent diffraction pattern from a nano-structured non-periodic object, before destroying it at 60,000 K. A novel X-ray camera assured single photon detection sensitivity by filtering out parasitic scattering and plasma radiation. The reconstructed image, obtained directly from the coherent pattern by phase retrieval through oversampling, shows no measurable damage, and extends to diffraction-limited resolution. A three-dimensional data set may be assembled from such images when copies of a reproducible sample are exposed to the beam one by one.

  14. Femtosecond Diffractive Imaging with a Soft-X-ray Free-Electron Laser

    SciTech Connect

    Chapman, H N; Barty, A; Bogan, M; Boutet, S; Frank, M; Hau-Riege, S P; Marchesini, S; Woods, B; Bajt, S; Benner, W H; London, R; Ploenjes-Palm, E; Kuhlmann, M; Treusch, R; Dusterer, S; Tschentscher, T; Schneider, J; Spiller, E; Moller, T; Bostedt, C; Hoener, M; Shapiro, D; Hodgson, K O; der Spoel, D v; Burmeister, F; Bergh, M; Caleman, C; Huldt, G; Seibert, M; Maia, F; Lee, R; Szoke, A; Timneanu, N; Hajdu, J

    2006-03-13

    Theory predicts that with an ultrashort and extremely bright coherent X-ray pulse, a single diffraction pattern may be recorded from a large macromolecule, a virus, or a cell before the sample explodes and turns into a plasma. Here we report the first experimental demonstration of this principle using the FLASH soft X-ray free-electron laser. An intense 25 fs, 4 x 10{sup 13} W/cm{sup 2} pulse, containing 10{sup 12} photons at 32 nm wavelength, produced a coherent diffraction pattern from a nano-structured non-periodic object, before destroying it at 60,000 K. A novel X-ray camera assured single photon detection sensitivity by filtering out parasitic scattering and plasma radiation. The reconstructed image, obtained directly from the coherent pattern by phase retrieval through oversampling, shows no measurable damage, and extends to diffraction-limited resolution. A three-dimensional data set may be assembled from such images when copies of a reproducible sample are exposed to the beam one by one.

  15. Laser versus intense pulsed light: Competing technologies in dermatology.

    PubMed

    Ross, E Victor

    2006-04-01

    Lasers have been competing with non-laser intense pulsed light (IPL) sources in the cosmetic arena over the past 10 years. Initially IPLs were somewhat cumbersome and accepted by a minority of "serious" practitioners. Recently, however, the popularity of full-face visible light skin rejuvenation, enhanced engineering of IPLs, and favorable cost versus many lasers, have lead to a proliferation of IPL devices. No longer a stepchild in the rejuvenation market, IPLs may overtake lasers as the devices of choice among most physicians. We review the pros and cons of lasers and IPLs within the context of design, cost, and other practical concerns for a typical office-based practice. PMID:16596659

  16. Laser warning receiver to identify the wavelength and angle of arrival of incident laser light

    DOEpatents

    Sinclair; Michael B.; Sweatt, William C.

    2010-03-23

    A laser warning receiver is disclosed which has up to hundreds of individual optical channels each optically oriented to receive laser light from a different angle of arrival. Each optical channel has an optical wedge to define the angle of arrival, and a lens to focus the laser light onto a multi-wavelength photodetector for that channel. Each multi-wavelength photodetector has a number of semiconductor layers which are located in a multi-dielectric stack that concentrates the laser light into one of the semiconductor layers according to wavelength. An electrical signal from the multi-wavelength photodetector can be processed to determine both the angle of arrival and the wavelength of the laser light.

  17. The ARGOS laser system: green light for ground layer adaptive optics at the LBT

    NASA Astrophysics Data System (ADS)

    Raab, Walfried; Rabien, Sebastian; Gässler, Wolfgang; Esposito, Simone; Barl, Lothar; Borelli, Jose; Daysenroth, Matthias; Gemperlein, Hans; Kulas, Martin; Ziegleder, Julian

    2014-07-01

    We report on the development of the laser system of ARGOS, the multiple laser guide star adaptive optics system for the Large Binocular Telescope (LBT). The system uses a total of six high powered, pulsed Nd:YAG lasers frequency-doubled to a wavelength of 532 nm to generate a set of three guide stars above each of the LBT telescopes. The position of each of the LGS constellations on sky as well as the relative position of the individual laser guide stars within this constellation is controlled by a set of steerable mirrors and a fast tip-tilt mirror within the laser system. The entire opto-mechanical system is housed in two hermetically sealed and thermally controlled enclosures on the SX and DX side of the LBT telescope. The laser beams are propagated through two refractive launch telescopes which focus the beams at an altitude of 12 km, creating a constellation of laser guide stars around a 4 arcminute diameter circle by means of Rayleigh scattering. In addition to the GLAO Rayleigh beacon system, ARGOS has also been designed for a possible future upgrade with a hybrid sodium laser - Rayleigh beacon combination, enabling diffraction limited operation. The ARGOS laser system was successfully installed at the LBT in April 2013. Extensive functional tests have been carried out and have verified the operation of the systems according to specifications. The alignment of the laser system with respect to the launch telescope was carried out during two more runs in June and October 2013, followed by the first propagation of laser light on sky in November 2013.

  18. Final Report: Cooling Molecules with Laser Light

    SciTech Connect

    Di Rosa, Michael D.

    2012-05-08

    Certain diatomic molecules are disposed to laser cooling in the way successfully applied to certain atoms and that ushered in a revolution in ultracold atomic physics, an identification first made at Los Alamos and which took root during this program. Despite their manipulation into numerous achievements, atoms are nonetheless mundane denizens of the quantum world. Molecules, on the other hand, with their internal degrees of freedom and rich dynamical interplay, provide considerably more complexity. Two main goals of this program were to demonstrate the feasibility of laser-cooling molecules to the same temperatures as laser-cooled atoms and introduce a means for collecting laser-cooled molecules into dense ensembles, a foundational start of studies and applications of ultracold matter without equivalence in atomic systems.

  19. NASA Now: Lasers and Light: STORRM

    NASA Video Gallery

    Byron Meadows, a laser systems engineer at NASA, describes his work on sensor testing for the Orion Relative Navigation Risk Mitigation, or STORRM, project. Learn why NASA wants to develop technolo...

  20. Progress on the prevention of stray light and diffraction effects on the Thai National Telescope

    NASA Astrophysics Data System (ADS)

    Buisset, Christophe; Prasit, Apirat; Leckngam, Apichat; Lépine, Thierry; Poshyajinda, Saran; Soonthornthum, Boonrucksar; Irawati, Puji; Richichi, Andrea; Sawangwit, Utane; Dhillon, Vik; Hardy, Liam K.

    2015-09-01

    The 2.4-m Thai National Telescope (TNT) is the main facility of the Thai National Observatory located on the Doi Inthanon, Thailand's highest mountain. The first astronomical images obtained at the TNT suffered from diffraction and stray light problems: bright spikes spread from bright stellar images over few arcminutes in the focal plane, and the images taken during observations in bright moon conditions were contaminated by high levels of stray light. We performed targeted investigations to identify the origin of these problems. In a first time, these investigations consisted of analyzing the irradiance distribution of defocused stellar images and of identifying the contributors. We concluded that these bright spikes around the bright stellar images were due to the chamfer and the wavefront error at the mirror edge. We thus installed an annular mask along the edge of the primary mirror that fully suppressed these spikes and we quantified the improvement by observing the double star Sirius. In a second time, we identified the contributors to the stray light by placing a pinhole camera at the TNT focal plane. Then, we designed a new baffle to improve the stray light rejection. The final design of the baffle comprises 21 diaphragms, is painted with an ordinary black paint and was designed, developed and installed on the TNT in less than 8 months. We assessed the improvement on the performance by measuring the variation of the stray light signal before and after installing the baffle in the telescope structure. These steps significantly improved the image quality and enhanced the rejection of the stray light at the focal plane level. In this paper, we present our investigations, we describe the method used to design the TNT baffle, and we present the improvement in quantitative terms.

  1. ERL R&D: Laser and Laser Light Transport

    SciTech Connect

    Sheehy, B.

    2010-01-01

    Operation of the photocathode gun in the ERL requires that a tightly controlled optical pulse train, consisting of temporally and spatially shaped pulses, be delivered at the photocathode in synchrony with the RF field in the gun cavity. The pulse train must also be dynamically variable, in order to tune or ramp up the current in the ERL. A laser was developed especially for this task by Lumera Laser GmbH, of Kaiserslautern Germany, under design supervision and review of the ERL project. Following the final design review, the laser was delivered in August 2009. Preliminary tests certifying its compliance with design specifications have been performed, with further tests planned following the final certification of the ERL laser room in January 2010. The development of the necessary spatial and temporal shaping techniques is an ongoing project: proof of principle experiments have been successfully carried out with a laser of similar pulse width, operating at 532 nm and 81.5 MHz. The next stage is to evaluate the application of these techniques and alternatives, using the operations laser. A transport line has been designed and the propagation of a shaped pulse through it to the photocathode simulated and tested experimentally. As the performance of the complete photocathode drive system is critical for ERL operation, an extensive set of diagnostics will be in place to monitor and maintain its performance. The block diagram in Fig. 1 breaks the optical system down into its basic components, which are discussed.

  2. Laser light stripe measurements assure correct piston assembly

    NASA Astrophysics Data System (ADS)

    Stein, Norbert; Frohn, Heiko

    1993-12-01

    Two VIKON-3D optical inspection systems assure the correct assembly of piston rings and guard rings in a new Volkswagen piston/rod assembly line. Both systems use laser light stripe measurements to locate and identify the relevant parts with high accuracy. The piston ring assembly is checked dynamically in video real time using laser light stripe and parallel projection techniques. In addition structured light is used to verify the correct piston/rod assembly. Both inspection systems are fully integrated into the manufacturing line. All types of pistons assembled can be checked without any mechanical changes to the measurement setup.

  3. A twin-mirrored galvanometer laser light sheet generator

    NASA Technical Reports Server (NTRS)

    Rhodes, David B.; Franke, John M.; Jones, Stephen B.; Leighty, Bradley D.

    1988-01-01

    A galvanometer mirror-based laser light sheet system has been developed for use in the Basic Aerodynamics Research Tunnel at NASA Langley. This system generates and positions single or multiple light sheets over aeronautical research models being tested in the low speed tunnel. This report describes a twin mirrored galvanometer laser light sheet generator and shows typical light sheet arrangements in use. With this system, illumination of smoke entrained in the flow over a delta wing model reveals the vortical flow produced by the separation of the flow at the leading edge of the model. The light sheet system has proven to be very adaptable and easy to use in sizing and positioning light sheets in wind tunnel applications.

  4. Influence of acoustic diffraction on laser-induced stress wave effects in absorbing media

    NASA Astrophysics Data System (ADS)

    Paltauf, Guenther; Frenz, Martin; Schmidt-Kloiber, Heinz

    1996-05-01

    Short pulses of laser radiation are capable of producing strong stress transients in absorbing materials. If the stress waves contain negative components, material can be fractured or even ablated. This study investigates the propagation of thermoelastic stress waves and in particular the occurrence of tensile stresses due to acoustic diffraction in front of a submerged optical fiber. Pulses with a duration of 6 ns from an optical parametric oscillator (OPO) were transmitted through optical quartz fibers into aqueous dye solution or gelatin. The absorption of the samples could be widely varied by tuning the wavelength of the OPO. Stress wave propagation and tensile stress induced cavitation were observed by use of a time gated video camera. Depending on the absorption of the sample, tensile stress induced cavitation could be observed either outside (at high absorption) or inside the laser irradiated volume (at low absorption) in front a submerged fiber tip, the latter at temperatures calculated to be below the boiling point. The experimental findings together with theoretical calculations demonstrate that the limited size of the stress wave source, leading to diffraction of the wave is the reason for the occurrence of tensile stress waves. This was further supported by the results obtained from the comparison of cavitation bubble formation at a rigid boundary (fiber submerged) and at a free boundary (fiber outside the liquid). In medical applications where fiber-transmitted laser pulses are applied, tensile stress can weaken the mechanical strength of the tissue. This may facilitate the onset of tissue ablation but might also cause unwanted side effects, which can occur even far outside the optically heated zone.

  5. Ultrafast electron microscopy and diffraction with laser-driven field emitters

    NASA Astrophysics Data System (ADS)

    Ropers, Claus

    2015-03-01

    Ultrafast structural dynamics in solids and nanostructures can be investigated by an increasing number of sophisticated electron and x-ray diffraction techniques. Electrons are particularly suited for this purpose, exhibiting high scattering cross-sections and allowing for beam control by versatile electrostatic or magnetic lens systems. The capabilities of time-resolved electron imaging techniques critically depend on the employed source of laser-driven ultrashort electron pulses. Nanoscopic sources offer exceptional possibilities for the generation of electron probe pulses with very short durations and high spatial beam coherence. In this talk, I will discuss recent progress in the development of ultrafast electron microscopy and diffraction based on nanoscopic photocathodes. In particular, we implemented ultrafast low-energy electron diffraction (ULEED) and ultrafast transmission electron microscopy (UTEM) driven by nonlinear photoemission from field emission tips. ULEED enables the study of structural changes with high temporal resolution and ultimate surface sensitivity, at sub-keV electron energies. As a first application of this technique, we studied the structural phase transition in a stripe-like polymer superstructure on freestanding monolayer graphene. An advanced UTEM instrument was realized by custom modifications of a standard transmission electron microscope, leading to electron focal spot sizes in the microscope's sample plane of about 10 nm and electron pulse durations of less than 700 fs. Utilizing these features, we investigate the quantum-coherent interaction between the ultrashort electron pulse and the optical near-field of an illuminated nanostructure. Finally, further applications and prospects of ultrafast electron imaging, diffraction and spectroscopy using nanoscale field emitters will be discussed.

  6. Laterally injected light-emitting diode and laser diode

    SciTech Connect

    Miller, Mary A.; Crawford, Mary H.; Allerman, Andrew A.

    2015-06-16

    A p-type superlattice is used to laterally inject holes into an III-nitride multiple quantum well active layer, enabling efficient light extraction from the active area. Laterally-injected light-emitting diodes and laser diodes can enable brighter, more efficient devices that impact a wide range of wavelengths and applications. For UV wavelengths, applications include fluorescence-based biological sensing, epoxy curing, and water purification. For visible devices, applications include solid state lighting and projection systems.

  7. Sound Velocity and Diffraction Intensity Measurements Based on Raman-Nath Theory of the Interaction of Light and Ultrasound

    ERIC Educational Resources Information Center

    Neeson, John F.; Austin, Stephen

    1975-01-01

    Describes a method for the measurement of the velocity of sound in various liquids based on the Raman-Nath theory of light-sound interaction. Utilizes an analog computer program to calculate the intensity of light scattered into various diffraction orders. (CP)

  8. Sub-Diffraction Limited Writing based on Laser Induced Periodic Surface Structures (LIPSS)

    PubMed Central

    He, Xiaolong; Datta, Anurup; Nam, Woongsik; Traverso, Luis M.; Xu, Xianfan

    2016-01-01

    Controlled fabrication of single and multiple nanostructures far below the diffraction limit using a method based on laser induced periodic surface structure (LIPSS) is presented. In typical LIPSS, multiple lines with a certain spatial periodicity, but often not well-aligned, were produced. In this work, well-controlled and aligned nanowires and nanogrooves with widths as small as 40 nm and 60 nm with desired orientation and length are fabricated. Moreover, single nanowire and nanogroove were fabricated based on the same mechanism for forming multiple, periodic structures. Combining numerical modeling and AFM/SEM analyses, it was found these nanostructures were formed through the interference between the incident laser radiation and the surface plasmons, the mechanism for forming LIPSS on a dielectric surface using a high power femtosecond laser. We expect that our method, in particular, the fabrication of single nanowires and nanogrooves could be a promising alternative for fabrication of nanoscale devices due to its simplicity, flexibility, and versatility. PMID:27721428

  9. Sub-Diffraction Limited Writing based on Laser Induced Periodic Surface Structures (LIPSS)

    NASA Astrophysics Data System (ADS)

    He, Xiaolong; Datta, Anurup; Nam, Woongsik; Traverso, Luis M.; Xu, Xianfan

    2016-10-01

    Controlled fabrication of single and multiple nanostructures far below the diffraction limit using a method based on laser induced periodic surface structure (LIPSS) is presented. In typical LIPSS, multiple lines with a certain spatial periodicity, but often not well-aligned, were produced. In this work, well-controlled and aligned nanowires and nanogrooves with widths as small as 40 nm and 60 nm with desired orientation and length are fabricated. Moreover, single nanowire and nanogroove were fabricated based on the same mechanism for forming multiple, periodic structures. Combining numerical modeling and AFM/SEM analyses, it was found these nanostructures were formed through the interference between the incident laser radiation and the surface plasmons, the mechanism for forming LIPSS on a dielectric surface using a high power femtosecond laser. We expect that our method, in particular, the fabrication of single nanowires and nanogrooves could be a promising alternative for fabrication of nanoscale devices due to its simplicity, flexibility, and versatility.

  10. Luminescent light source for laser pumping and laser system containing same

    DOEpatents

    Hamil, Roy A.; Ashley, Carol S.; Brinker, C. Jeffrey; Reed, Scott; Walko, Robert J.

    1994-01-01

    The invention relates to a pumping lamp for use with lasers comprising a porous substrate loaded with a component capable of emitting light upon interaction of the component with exciting radiation and a source of exciting radiation. Preferably, the pumping lamp comprises a source of exciting radiation, such as an electron beam, and an aerogel or xerogel substrate loaded with a component capable of interacting with the exciting radiation, e.g., a phosphor, to produce light, e.g., visible light, of a suitable band width and of a sufficient intensity to generate a laser beam from a laser material.

  11. Stray-light suppression with high-collection efficiency in laser light-scattering experiments

    NASA Technical Reports Server (NTRS)

    Deilamian, K.; Gillaspy, J. D.; Kelleher, D. E.

    1992-01-01

    An optical system is described for collecting a large fraction of fluorescent light emitted isotropically from a cylindrical interaction region. While maintaining an overall detection efficiency of 9 percent, the system rejects, by more than 12 orders of magnitude, incident laser light along a single axis that intersects the interaction region. Such a system is useful for a wide variety of light-scattering experiments in which high-collection efficiency is desirable, but in which light from an incident laser beam must be rejected without resorting to spectral filters.

  12. The 'Magic Light': A Discussion on Laser Ethics.

    PubMed

    Stylianou, Andreas; Talias, Michael A

    2015-08-01

    Innovations in technology and science form novel fields that, although beneficial, introduce new bio-ethical issues. In their short history, lasers have greatly influenced our everyday lives, especially in medicine. This paper focuses particularly on medical and para-medical laser ethics and their origins, and presents the complex relationships within laser ethics through a three-dimensional matrix model. The term 'laser' and the myth of the 'magic light' can be identified as landmarks for laser related ethical issues. These ethical issues are divided into five major groups: (1) media, marketing, and advertising; (2) economic outcomes; (3) user training; (4) the user-patient/client relationship; and (5) other issues. In addition, issues arising from two of the most common applications of lasers, laser eye surgery and laser tattoo removal, are discussed. The aim of this paper is to demonstrate that the use of medical and para-medical lasers has so greatly influenced our lives that the scientific community must initiate an earnest discussion of medical laser ethics.

  13. The 'Magic Light': A Discussion on Laser Ethics.

    PubMed

    Stylianou, Andreas; Talias, Michael A

    2015-08-01

    Innovations in technology and science form novel fields that, although beneficial, introduce new bio-ethical issues. In their short history, lasers have greatly influenced our everyday lives, especially in medicine. This paper focuses particularly on medical and para-medical laser ethics and their origins, and presents the complex relationships within laser ethics through a three-dimensional matrix model. The term 'laser' and the myth of the 'magic light' can be identified as landmarks for laser related ethical issues. These ethical issues are divided into five major groups: (1) media, marketing, and advertising; (2) economic outcomes; (3) user training; (4) the user-patient/client relationship; and (5) other issues. In addition, issues arising from two of the most common applications of lasers, laser eye surgery and laser tattoo removal, are discussed. The aim of this paper is to demonstrate that the use of medical and para-medical lasers has so greatly influenced our lives that the scientific community must initiate an earnest discussion of medical laser ethics. PMID:25027860

  14. Single-Shot Diffractive Imaging with a Table-Top Femtosecond Soft X-Ray Laser-Harmonics Source

    SciTech Connect

    Ravasio, A.; Gauthier, D.; Billon, M.; Caumes, J-P.; Garzella, D.; Geleoc, M.; Gobert, O.; Hergott, J-F.; Pena, A-M.; Perez, H.; Carre, B.; Maia, F. R. N. C.; Bourhis, E.; Gierak, J.; Madouri, A.; Mailly, D.; Schiedt, B.; Fajardo, M.; Gautier, J.; Zeitoun, P.

    2009-07-10

    Coherent x-ray diffractive imaging is a powerful method for studies on nonperiodic structures on the nanoscale. Access to femtosecond dynamics in major physical, chemical, and biological processes requires single-shot diffraction data. Up to now, this has been limited to intense coherent pulses from a free electron laser. Here we show that laser-driven ultrashort x-ray sources offer a comparatively inexpensive alternative. We present measurements of single-shot diffraction patterns from isolated nano-objects with a single 20 fs pulse from a table-top high-harmonic x-ray laser. Images were reconstructed with a resolution of 119 nm from the single shot and 62 nm from multiple shots.

  15. Influence of laser light on bioimplants used in otorhinolaryngology.

    PubMed

    Siedek, Vanessa; Nehls, Kristina; Zur Nieden, Katrin; Leunig, Andreas; Sroka, Ronald

    2014-05-01

    In otorhinolaryngology, dermatology and reconstructive surgery biomaterials as implants and a variety of lasers are used. Laser light applied near to an implant could have the risk to damage these materials. Therefore, their resistance exposed to laser light is of interest. A diode laser emitting at 940 nm and a CO2 laser were used to investigate its effects to the biomaterials Bioverit®, Medpor® and Palacos®, and in addition, an excised implant containing Medpor® and nasal turbinate tissue, excised and fixed in formalin. The macro- and microscopic changes of the material, temperature development during laser energy application in dependency to distance of fibre and material, time of exposure and applied power were investigated. Interaction of diode laser light with Bioverit® (0 mm distance, 360 s, 10 W, 3,600 J) resulted in minimal microscopic effects in direct contact of with the fibre. Using Medpor® (1 mm, 10s, 10 W, 100 J) resulted in melting and perforation. In the case of Palacos® (0.6 mm, 10s, 10 W, 100 J), melting occurred creating a flat excavation. The effect to Medpor® in nasal turbinate (1-2 mm, 10s, 10 W, 100 J) showed tissue denaturation and carbonisation and creation of a hole. The interaction of the CO2 laser with Bioverit® (3 cm, 0.5, 1 and 5 s, 2, 10 or 20 W) induced melting and discolouring resulting finally in a perforating hole. Depending on the material, first damage starts 10 s after an impact of 100 J (threshold value). So interaction between laser energy and biomaterials occurs. This should be carefully considered during clinical laser treatments especially nearby implants.

  16. Comparison between ray-tracing and physical optics for the computation of light absorption in capillaries--the influence of diffraction and interference.

    PubMed

    Qin, Yuan; Michalowski, Andreas; Weber, Rudolf; Yang, Sen; Graf, Thomas; Ni, Xiaowu

    2012-11-19

    Ray-tracing is the commonly used technique to calculate the absorption of light in laser deep-penetration welding or drilling. Since new lasers with high brilliance enable small capillaries with high aspect ratios, diffraction might become important. To examine the applicability of the ray-tracing method, we studied the total absorptance and the absorbed intensity of polarized beams in several capillary geometries. The ray-tracing results are compared with more sophisticated simulations based on physical optics. The comparison shows that the simple ray-tracing is applicable to calculate the total absorptance in triangular grooves and in conical capillaries but not in rectangular grooves. To calculate the distribution of the absorbed intensity ray-tracing fails due to the neglected interference, diffraction, and the effects of beam propagation in the capillaries with sub-wavelength diameter. If diffraction is avoided e.g. with beams smaller than the entrance pupil of the capillary or with very shallow capillaries, the distribution of the absorbed intensity calculated by ray-tracing corresponds to the local average of the interference pattern found by physical optics.

  17. Visible light dynamical diffraction in a 1-D photonic crystal-based interferometer with an extremely thin spacer layer

    NASA Astrophysics Data System (ADS)

    Prudnikov, I. R.

    2016-01-01

    Properties of light diffraction in a Fabry-Pérot-like interferometer composed of two 1-D photonic crystals and a nanometer-thick spacer layer are analytically investigated. It is shown that the resonant enhancement of light wave intensity in such a layer is possible because of light dynamical diffraction from the photonic crystals of the interferometer. Numerical simulations of (i) light reflectivity and transmittance curves of the interferometer having an ultra-thin spacer layer (its thickness changes from less than 1 nm to about 10 nm) and (ii) the resonant distribution of the light wave intensity in the vicinity of the layer are performed. Based on the numerical simulations, potentialities for the determination of the structural parameters (e.g., thicknesses and refraction indexes) of ultra-thin spacer films are discussed. A difference is found to appear in resonant intensity enhancements inside the ultra-thin spacer layers between s- and p-polarized light waves.

  18. Development of diffractive XUV-VUV light extractors for fusion plasma diagnostic

    NASA Astrophysics Data System (ADS)

    Stutman, D.; Caravelli, G.; Delgado-Aparicio, L.; Finkenthal, M.; Tritz, K.; Kaita, R.; Roquemore, L.

    2009-11-01

    The diagnostic and control of next generation MFE and ICF fusion experiments will require optical light extractors capable of withstanding intense plasma and radiation exposure. A solution applicable from the XUV to the infrared is to use free-standing diffractive optics such as transmission gratings or zone plates. Here we present results on XUV-VUV diffractive extractors for the diagnostic of boundary MFE plasmas. For the VUV range we developed Si transmission gratings having 1 μm period, 5 μm thickness, 40% open fraction, 1x2 mm active area, and coated with Ni, while for the XUV range we use SiN gratings having 0.2 μm period, 0.3 μm thickness, 1x1 mm area, and coated with Ta. The grating extractors are spectrally and spatially calibrated in the laboratory using a newly developed extended XUV-VUV source and will be employed for imaging spectrometry on the NSTX experiment. The operational characteristics of the extended source and first space resolved XUV-VUV spectra will be presented. Work supported by DoE Grant DE-FG02-99ER54523 at JHU and Contract DE-AC02-09CH11466 at PU.

  19. Anisotropic Light Diffraction by Ultrasound in Crystals with Strong Acoustic Anisotropy

    NASA Astrophysics Data System (ADS)

    Voloshin, Andrey S.; Balakshy, Vladimir I.

    In modern acousto-optics, crystalline materials are used predominantly for manufacturing acousto-optic instruments. Among these materials, such crystals as paratellurite, tellurium, calomel, TAS and some others occupy a prominent place, which are distinguished by exceptionally large anisotropy of acoustic properties. In this work, the influence of acoustic beam energy walk-off on characteristics of Bragg diffraction of light is studied by the example of tellurium crystal. It is shown that the walk-off can substantially change angular and frequency ranges, resulting in their narrowing or broadening subject to position of the operating point in the Bragg angle frequency characteristic. Coefficients of broadening are introduced for characterization of this effect.

  20. Laser remote sensing of backscattered light from a target sample

    DOEpatents

    Sweatt, William C.; Williams, John D.

    2008-02-26

    A laser remote sensing apparatus comprises a laser to provide collimated excitation light at a wavelength; a sensing optic, comprising at least one optical element having a front receiving surface to focus the received excitation light onto a back surface comprising a target sample and wherein the target sample emits a return light signal that is recollimated by the front receiving surface; a telescope for collecting the recollimated return light signal from the sensing optic; and a detector for detecting and spectrally resolving the return light signal. The back surface further can comprise a substrate that absorbs the target sample from an environment. For example the substrate can be a SERS substrate comprising a roughened metal surface. The return light signal can be a surface-enhanced Raman signal or laser-induced fluorescence signal. For fluorescence applications, the return signal can be enhanced by about 10.sup.5, solely due to recollimation of the fluorescence return signal. For SERS applications, the return signal can be enhanced by 10.sup.9 or more, due both to recollimation and to structuring of the SERS substrate so that the incident laser and Raman scattered fields are in resonance with the surface plasmons of the SERS substrate.

  1. Modular sub-wavelength diffractive light modulator for high-definition holographic displays

    NASA Astrophysics Data System (ADS)

    Stahl, Richard; Rochus, Veronique; Rottenberg, Xavier; Cosemans, Stefan; Haspeslagh, Luc; Severi, Simone; Van der Plas, Geert; Lafruit, Gauthier; Donnay, Stephane

    2013-02-01

    Holography is undoubtedly the ultimate 3D visualization technology, offering true 3D experience with all the natural depth cues, without the undesirable side-effects of current stereoscopic systems (uncomfortable glasses, strained eyes, fatiguing experience). Realization of a high-definition holographic display however requires a number of breakthroughs from existing prototypes. One of the main challenges lies in technology scaling, as holography is based on light diffraction and interference - to achieve wide viewing angles, the light-modulating pixels need to be spaced close to or below the wavelength of the used visible light. Furthermore, achieving high 3D image quality, hundreds of millions of such individually programmable pixels are needed. As a solution, we develop a modular sub-wavelength light modulator, consisting of three main sub-systems: the optical sub-system, comprising a 2D array of sub-wavelength pixels; the driver sub-system for individual pixel control, and the holographic computational engine. Based on conclusions from our state-of-the art studies, numerous experiments and holographic demonstrators, we have focused on reflective phase-modulating MEMS-based system and its scaling beyond 500nm pitch. We have devised a unique binary-programmable phase-modulating pixel architecture realizing vertical pixel displacement of up to 150nm at 500nm by 500nm pixel pitch, while sustaining low operating voltages compatible with CMOS driver circuitry. IMEC SiGe MEMS technology enables integration of the CMOS pixel-line drivers, scan-line drivers and I/O circuits underneath the 2D MEMS array, resulting in a compact and modular single-chip system design. Refresh rates of few hundred frames per second are achieved using our patented segmented driver-array architecture. Integrated circuits implementing parallel holographic computational engines can be added to the module using advanced 3D stacking technology. Herein we further report on our progress in realizing

  2. Breaking the diffraction barrier outside of the optical near-field with bright, collimated light from nanometric apertures.

    PubMed

    Stark, Peter R H; Halleck, Allison E; Larson, Dale N

    2007-11-27

    The optical diffraction limit has been the dominant barrier to achieving higher optical resolution in the fields of microscopy, photolithography, and optical data storage. We present here an approach toward imaging below the diffraction barrier. Through the exposure of photosensitive films placed a finite and known distance away from nanoscale, zero-mode apertures in thin metallic films, we show convincing, physical evidence that the propagating component of light emerging from these apertures shows a very strong degree of collimation well past the maximum extent of the near-field (lambda(0)/4n-lambda(0)/2n). Up to at least 2.5 wavelengths away from the apertures, the transmitted light exhibits subdiffraction limit irradiance patterns. These unexpected results are not explained by standard diffraction theory or nanohole-based "beaming" rationalizations. This method overcomes the diffraction barrier and makes super-resolution fluorescence imaging practical.

  3. Breaking the diffraction barrier outside of the optical near-field with bright, collimated light from nanometric apertures

    PubMed Central

    Stark, Peter R. H.; Halleck, Allison E.; Larson, Dale N.

    2007-01-01

    The optical diffraction limit has been the dominant barrier to achieving higher optical resolution in the fields of microscopy, photolithography, and optical data storage. We present here an approach toward imaging below the diffraction barrier. Through the exposure of photosensitive films placed a finite and known distance away from nanoscale, zero-mode apertures in thin metallic films, we show convincing, physical evidence that the propagating component of light emerging from these apertures shows a very strong degree of collimation well past the maximum extent of the near-field (λ0/4n–λ0/2n). Up to at least 2.5 wavelengths away from the apertures, the transmitted light exhibits subdiffraction limit irradiance patterns. These unexpected results are not explained by standard diffraction theory or nanohole-based “beaming” rationalizations. This method overcomes the diffraction barrier and makes super-resolution fluorescence imaging practical. PMID:18024583

  4. X-ray laser diffraction for structure determination of the rhodopsin-arrestin complex

    PubMed Central

    Zhou, X. Edward; Gao, Xiang; Barty, Anton; Kang, Yanyong; He, Yuanzheng; Liu, Wei; Ishchenko, Andrii; White, Thomas A.; Yefanov, Oleksandr; Han, Gye Won; Xu, Qingping; de Waal, Parker W.; Suino-Powell, Kelly M.; Boutet, Sébastien; Williams, Garth J.; Wang, Meitian; Li, Dianfan; Caffrey, Martin; Chapman, Henry N.; Spence, John C.H.; Fromme, Petra; Weierstall, Uwe; Stevens, Raymond C.; Cherezov, Vadim; Melcher, Karsten; Xu, H. Eric

    2016-01-01

    Serial femtosecond X-ray crystallography (SFX) using an X-ray free electron laser (XFEL) is a recent advancement in structural biology for solving crystal structures of challenging membrane proteins, including G-protein coupled receptors (GPCRs), which often only produce microcrystals. An XFEL delivers highly intense X-ray pulses of femtosecond duration short enough to enable the collection of single diffraction images before significant radiation damage to crystals sets in. Here we report the deposition of the XFEL data and provide further details on crystallization, XFEL data collection and analysis, structure determination, and the validation of the structural model. The rhodopsin-arrestin crystal structure solved with SFX represents the first near-atomic resolution structure of a GPCR-arrestin complex, provides structural insights into understanding of arrestin-mediated GPCR signaling, and demonstrates the great potential of this SFX-XFEL technology for accelerating crystal structure determination of challenging proteins and protein complexes. PMID:27070998

  5. Carrier-envelope phase mapping in laser-induced electron diffraction

    NASA Astrophysics Data System (ADS)

    Geiseler, Henning; Ishii, Nobuhisa; Kaneshima, Keisuke; Geier, Florian; Kanai, Teruto; Tolstikhin, Oleg I.; Morishita, Toru; Itatani, Jiro

    2016-09-01

    We present laser-induced electron diffraction measurements of elastic differential scattering cross sections (DCSs) of a photoelectron on the parent ion for argon, krypton, and xenon, using waveform-controlled few-cycle pulses. Considering only cutoff electrons and employing the adiabatic theory for the analysis enables us to eliminate ambiguities in extracting the DCSs from experimental spectra. Contrary to previous works, which mainly focused on the angular dependence of the DCS, our method allows us to extract also its dependence on the scattering momentum. In the case of xenon, we demonstrate how this method can be used to obtain the complete angular and momentum dependence of the DCS in a range of these variables determined by the pulse. The obtained results are compared to theoretical calculations based on the single-active-electron approximation, which shows a high level of agreement. Further investigations may provide opportunities to study multielectron effects when more advanced theoretical models become available.

  6. Diffractive elements manufactured by grey tone mask and global laser lightning for transportation applications

    NASA Astrophysics Data System (ADS)

    Quentel, F.; Boehlen, K.; Fieret, J.; Holmes, A.; Meyrueis, P.; Raulot, V.

    2011-06-01

    We report on a technology for multi-level microstructures manufacturing. Results are presented in the field of multilevel diffractive optical elements (DOEs) fabrication. The DOEs presented as examples are Fresnel lenses and Fourier computer generated holograms, calculated by means of a conventional Iterative Fourier Transform Algorithm. The DOEs have a typical pixel dimension of 5x5 μm2 and are up to 512 by 512 pixels in size. The fabrication technique is based on polymer laser ablation through a chrome-on-quartz half-tone mask with a demagnifying high NA lens. In our case, the mask is imaged onto the polymer with a 5x, 0.13 NA reduction lens. The experimental results are presented and discussed.

  7. X-ray laser diffraction for structure determination of the rhodopsin-arrestin complex.

    PubMed

    Zhou, X Edward; Gao, Xiang; Barty, Anton; Kang, Yanyong; He, Yuanzheng; Liu, Wei; Ishchenko, Andrii; White, Thomas A; Yefanov, Oleksandr; Han, Gye Won; Xu, Qingping; de Waal, Parker W; Suino-Powell, Kelly M; Boutet, Sébastien; Williams, Garth J; Wang, Meitian; Li, Dianfan; Caffrey, Martin; Chapman, Henry N; Spence, John C H; Fromme, Petra; Weierstall, Uwe; Stevens, Raymond C; Cherezov, Vadim; Melcher, Karsten; Xu, H Eric

    2016-01-01

    Serial femtosecond X-ray crystallography (SFX) using an X-ray free electron laser (XFEL) is a recent advancement in structural biology for solving crystal structures of challenging membrane proteins, including G-protein coupled receptors (GPCRs), which often only produce microcrystals. An XFEL delivers highly intense X-ray pulses of femtosecond duration short enough to enable the collection of single diffraction images before significant radiation damage to crystals sets in. Here we report the deposition of the XFEL data and provide further details on crystallization, XFEL data collection and analysis, structure determination, and the validation of the structural model. The rhodopsin-arrestin crystal structure solved with SFX represents the first near-atomic resolution structure of a GPCR-arrestin complex, provides structural insights into understanding of arrestin-mediated GPCR signaling, and demonstrates the great potential of this SFX-XFEL technology for accelerating crystal structure determination of challenging proteins and protein complexes.

  8. X-ray laser diffraction for structure determination of the rhodopsin-arrestin complex.

    PubMed

    Zhou, X Edward; Gao, Xiang; Barty, Anton; Kang, Yanyong; He, Yuanzheng; Liu, Wei; Ishchenko, Andrii; White, Thomas A; Yefanov, Oleksandr; Han, Gye Won; Xu, Qingping; de Waal, Parker W; Suino-Powell, Kelly M; Boutet, Sébastien; Williams, Garth J; Wang, Meitian; Li, Dianfan; Caffrey, Martin; Chapman, Henry N; Spence, John C H; Fromme, Petra; Weierstall, Uwe; Stevens, Raymond C; Cherezov, Vadim; Melcher, Karsten; Xu, H Eric

    2016-01-01

    Serial femtosecond X-ray crystallography (SFX) using an X-ray free electron laser (XFEL) is a recent advancement in structural biology for solving crystal structures of challenging membrane proteins, including G-protein coupled receptors (GPCRs), which often only produce microcrystals. An XFEL delivers highly intense X-ray pulses of femtosecond duration short enough to enable the collection of single diffraction images before significant radiation damage to crystals sets in. Here we report the deposition of the XFEL data and provide further details on crystallization, XFEL data collection and analysis, structure determination, and the validation of the structural model. The rhodopsin-arrestin crystal structure solved with SFX represents the first near-atomic resolution structure of a GPCR-arrestin complex, provides structural insights into understanding of arrestin-mediated GPCR signaling, and demonstrates the great potential of this SFX-XFEL technology for accelerating crystal structure determination of challenging proteins and protein complexes. PMID:27070998

  9. Laser and Light-Based Aesthetics in Men.

    PubMed

    Green, Jeremy B; Metelitsa, Andrei I; Kaufman, Joely; Keaney, Terrence

    2015-09-01

    Men represent an important evolving segment of the cosmetic market. With the growing acceptability of cosmetic procedures along with societal and workplace pressure to maintain youthfulness, men increasingly seek the advice of aesthetic practitioners. Despite this so-called "Menaissance," there is a paucity of published literature regarding laser and light treatments of male skin. Herein the differences in male cutaneous physiology are addressed, followed by a review of light-based treatment of conditions largely unique to male skin, pseudofolliculitis barbae, and rhinophyma. Next, the publications related to laser treatment of male skin specifically are examined. We conclude with a discussion of personal observations derived from clinical experience with laser and light-based treatments in men.

  10. Laser and Light-Based Aesthetics in Men.

    PubMed

    Green, Jeremy B; Metelitsa, Andrei I; Kaufman, Joely; Keaney, Terrence

    2015-09-01

    Men represent an important evolving segment of the cosmetic market. With the growing acceptability of cosmetic procedures along with societal and workplace pressure to maintain youthfulness, men increasingly seek the advice of aesthetic practitioners. Despite this so-called "Menaissance," there is a paucity of published literature regarding laser and light treatments of male skin. Herein the differences in male cutaneous physiology are addressed, followed by a review of light-based treatment of conditions largely unique to male skin, pseudofolliculitis barbae, and rhinophyma. Next, the publications related to laser treatment of male skin specifically are examined. We conclude with a discussion of personal observations derived from clinical experience with laser and light-based treatments in men. PMID:26355628

  11. Diffraction Revisited: Position of Diffraction Spots upon Rotation of a Transmission Grating

    ERIC Educational Resources Information Center

    Vollmer, Michael

    2005-01-01

    Diffraction gratings are often used in the laboratory to determine the wavelength of laser light. What happens to the spots on the screen if the grating is rotated in this set-up? The answer is nontrivial and instructive.

  12. Toward unsupervised single-shot diffractive imaging of heterogeneous particles using X-ray free-electron lasers.

    PubMed

    Park, Hyung Joo; Loh, N Duane; Sierra, Raymond G; Hampton, Christina Y; Starodub, Dmitri; Martin, Andrew V; Barty, Anton; Aquila, Andrew; Schulz, Joachim; Steinbrener, Jan; Shoeman, Robert L; Lomb, Lukas; Kassemeyer, Stephan; Bostedt, Christoph; Bozek, John; Epp, Sascha W; Erk, Benjamin; Hartmann, Robert; Rolles, Daniel; Rudenko, Artem; Rudek, Benedikt; Foucar, Lutz; Kimmel, Nils; Weidenspointner, Georg; Hauser, Guenter; Holl, Peter; Pedersoli, Emanuele; Liang, Mengning; Hunter, Mark S; Gumprecht, Lars; Coppola, Nicola; Wunderer, Cornelia; Graafsma, Heinz; Maia, Filipe R N C; Ekeberg, Tomas; Hantke, Max; Fleckenstein, Holger; Hirsemann, Helmut; Nass, Karol; Tobias, Herbert J; Farquar, George R; Benner, W Henry; Hau-Riege, Stefan; Reich, Christian; Hartmann, Andreas; Soltau, Heike; Marchesini, Stefano; Bajt, Sasa; Barthelmess, Miriam; Strueder, Lothar; Ullrich, Joachim; Bucksbaum, Philip; Frank, Matthias; Schlichting, Ilme; Chapman, Henry N; Bogan, Michael J; Elser, Veit

    2013-11-18

    Single shot diffraction imaging experiments via X-ray free-electron lasers can generate as many as hundreds of thousands of diffraction patterns of scattering objects. Recovering the real space contrast of a scattering object from these patterns currently requires a reconstruction process with user guidance in a number of steps, introducing severe bottlenecks in data processing. We present a series of measures that replace user guidance with algorithms that reconstruct contrasts in an unsupervised fashion. We demonstrate the feasibility of automating the reconstruction process by generating hundreds of contrasts obtained from soot particle diffraction experiments.

  13. Toward unsupervised single-shot diffractive imaging of heterogeneous particles using X-ray free-electron lasers.

    PubMed

    Park, Hyung Joo; Loh, N Duane; Sierra, Raymond G; Hampton, Christina Y; Starodub, Dmitri; Martin, Andrew V; Barty, Anton; Aquila, Andrew; Schulz, Joachim; Steinbrener, Jan; Shoeman, Robert L; Lomb, Lukas; Kassemeyer, Stephan; Bostedt, Christoph; Bozek, John; Epp, Sascha W; Erk, Benjamin; Hartmann, Robert; Rolles, Daniel; Rudenko, Artem; Rudek, Benedikt; Foucar, Lutz; Kimmel, Nils; Weidenspointner, Georg; Hauser, Guenter; Holl, Peter; Pedersoli, Emanuele; Liang, Mengning; Hunter, Mark S; Gumprecht, Lars; Coppola, Nicola; Wunderer, Cornelia; Graafsma, Heinz; Maia, Filipe R N C; Ekeberg, Tomas; Hantke, Max; Fleckenstein, Holger; Hirsemann, Helmut; Nass, Karol; Tobias, Herbert J; Farquar, George R; Benner, W Henry; Hau-Riege, Stefan; Reich, Christian; Hartmann, Andreas; Soltau, Heike; Marchesini, Stefano; Bajt, Sasa; Barthelmess, Miriam; Strueder, Lothar; Ullrich, Joachim; Bucksbaum, Philip; Frank, Matthias; Schlichting, Ilme; Chapman, Henry N; Bogan, Michael J; Elser, Veit

    2013-11-18

    Single shot diffraction imaging experiments via X-ray free-electron lasers can generate as many as hundreds of thousands of diffraction patterns of scattering objects. Recovering the real space contrast of a scattering object from these patterns currently requires a reconstruction process with user guidance in a number of steps, introducing severe bottlenecks in data processing. We present a series of measures that replace user guidance with algorithms that reconstruct contrasts in an unsupervised fashion. We demonstrate the feasibility of automating the reconstruction process by generating hundreds of contrasts obtained from soot particle diffraction experiments. PMID:24514385

  14. Characterization of inhalation aerosols: a critical evaluation of cascade impactor analysis and laser diffraction technique.

    PubMed

    de Boer, A H; Gjaltema, D; Hagedoorn, P; Frijlink, H W

    2002-12-01

    Cascade impactor analysis is the standard technique for in vitro characterization of aerosol clouds generated by medical aerosol generators. One important reason for using this inertial separation principle is that drug fractions are classified into aerodynamic size ranges that are relevant to the deposition in the respiratory tract. Measurement of these fractions with chemical detection methods enables establishment of the particle size distribution of the drug in the presence of excipients. However, the technique is laborious and time consuming and most of the devices used for inhaler evaluation lack sufficient possibilities for automation. In addition to that, impactors often have to be operated under conditions for which they were not designed and calibrated. Particularly, flow rates through impactors are increased to values at which the flow through the nozzles is highly turbulent. This has an uncontrolled influence on the collection efficiencies and cut-off curves of these nozzles. Moreover, the cut-off value varies with the flow rate through an impactor nozzle. On the other hand, the high air flow resistances of most impactors are rather restricting to the attainable (fixed) inspiratory flow curves through these devices. Especially for breath actuated dry powder inhalers, higher flow rates and flow increase rates may be desirable than can be achieved in combination with a particular type of impactor. In this paper, the applicability of laser diffraction technology is evaluated as a very fast and highly reliable alternative for cascade impactor analysis. With this technique, aerodynamic diameters cannot be measured, but for comparative evaluation and development, comprising most in vitro applications, this is not necessary. Laser diffraction has excellent possibilities for automated recording of data and testing conditions, and the size classes are independent of the flow rate. Practical limitations can be overcome by using a special inhaler adapter which

  15. Near-diffraction-limited,35.4 W laser-diode end-pumped Nd:YVO4 slab laser operating at 1342 nm.

    PubMed

    Yan, Ying; Zhang, Hengli; Liu, Yang; Yu, Xilong; Zhang, Huaijin; He, Jingliang; Xin, Jianguo

    2009-07-15

    A diode stack end-pumped Nd:YVO4 slab laser at 1342 nm with near-diffraction-limited beam quality by using a hybrid resonator was presented. At a pump power of 139.5 W, laser power of 35.4 W was obtained with a conversion efficiency of 25.4% of the laser diode to laser output. The beam quality M2 factors were measured to be 1.2 in the unstable direction and 1.3 in the stable direction at the output power of 29 W. PMID:19823516

  16. Near-diffraction-limited,35.4 W laser-diode end-pumped Nd:YVO4 slab laser operating at 1342 nm.

    PubMed

    Yan, Ying; Zhang, Hengli; Liu, Yang; Yu, Xilong; Zhang, Huaijin; He, Jingliang; Xin, Jianguo

    2009-07-15

    A diode stack end-pumped Nd:YVO4 slab laser at 1342 nm with near-diffraction-limited beam quality by using a hybrid resonator was presented. At a pump power of 139.5 W, laser power of 35.4 W was obtained with a conversion efficiency of 25.4% of the laser diode to laser output. The beam quality M2 factors were measured to be 1.2 in the unstable direction and 1.3 in the stable direction at the output power of 29 W.

  17. Destruction-and-diffraction by X-ray free-electron laser.

    PubMed

    Wang, Jimin

    2016-09-01

    It is common knowledge that macromolecular crystals are damaged by the X-rays they are exposed to during conventional data collection. One of the claims made about the crystallographic data collection now being collected using X-ray free-electron lasers (XFEL) is that they are unaffected by radiation damage. XFEL data sets are assembled by merging data obtained from a very large number of crystals, each of which is exposed to a single femtosecond pulse of radiation, the duration of which is so short that diffraction occurs before the damage done to the crystal has time to become manifest, i.e. "diffraction-before-destruction." However, recent theoretical studies have shown that many of the elemental electronic processes that ultimately result in the destruction of such crystals occur during a single pulse. It is predicted that the amplitudes of atomic scattering factor could be reduced by as much as 75% within the first 5 femtoseconds of such pulses, and that different atoms will respond in different ways. Experimental evidence is provided here that these predictions are correct.

  18. Applications of laser wakefield accelerator-based light sources

    NASA Astrophysics Data System (ADS)

    Albert, Félicie; Thomas, Alec G. R.

    2016-11-01

    Laser-wakefield accelerators (LWFAs) were proposed more than three decades ago, and while they promise to deliver compact, high energy particle accelerators, they will also provide the scientific community with novel light sources. In a LWFA, where an intense laser pulse focused onto a plasma forms an electromagnetic wave in its wake, electrons can be trapped and are now routinely accelerated to GeV energies. From terahertz radiation to gamma-rays, this article reviews light sources from relativistic electrons produced by LWFAs, and discusses their potential applications. Betatron motion, Compton scattering and undulators respectively produce x-rays or gamma-rays by oscillating relativistic electrons in the wakefield behind the laser pulse, a counter-propagating laser field, or a magnetic undulator. Other LWFA-based light sources include bremsstrahlung and terahertz radiation. We first evaluate the performance of each of these light sources, and compare them with more conventional approaches, including radio frequency accelerators or other laser-driven sources. We have then identified applications, which we discuss in details, in a broad range of fields: medical and biological applications, military, defense and industrial applications, and condensed matter and high energy density science.

  19. Generation of Hermite–Gaussian modes of high-power femtosecond laser radiation using binary-phase diffractive optical elements

    NASA Astrophysics Data System (ADS)

    Larkin, A. S.; Pushkarev, D. V.; Degtyarev, S. A.; Khonina, S. N.; Savel'ev, A. B.

    2016-08-01

    We present the results of experiments on generation of Hermite–Gaussian modes up to the third order inclusive using binary-phase diffractive optical elements (DOEs) illuminated by subterawatt femtosecond laser pulses. We perform a compariosn of the mode formation using DOEs designed by the kinoform method and the fractional coding technique, when the DOEs are illuminated by both femtosecond radiation and cw laser radiation at close wavelengths.

  20. Designing Light Beam Transmittance Measuring Tool Using a Laser Pointer

    NASA Astrophysics Data System (ADS)

    Nuroso, H.; Kurniawan, W.; Marwoto, P.

    2016-08-01

    A simple instrument used for measuring light beam transmittance percentage made of window film has been developed. The instrument uses a laser pointer of 405 nm and 650 nm ±10% as a light source. Its accuracy approaches 80%. Transmittance data was found by comparing the light beam before and after passing the window film. The light intensity measuring unit was deleted by splitting the light source into two beams through a beam splitter. The light beam was changed into resistance by a NORP12 LDR sensor designed at a circuit of voltage divider rule of Khirchoff's laws. This conversion system will produce light beam intensity received by the sensor to become an equal voltage. This voltage will, then, be presented on the computer screen in the form of a real time graph via a 2.0 USB data transfer.

  1. Control of Laser High-Harmonic Generation with Counterpropagating Light

    NASA Astrophysics Data System (ADS)

    Voronov, S. L.; Kohl, I.; Madsen, J. B.; Simmons, J.; Terry, N.; Titensor, J.; Wang, Q.; Peatross, J.

    2001-09-01

    Relatively weak counterpropagating light is shown to disrupt the emission of laser high-harmonic generation. Harmonic orders ranging from the teens to the low thirties produced by a 30-femtosecond pulse in a narrow argon jet are ``shut down'' with a contrast as high as 2 orders of magnitude by a chirped 1-picosecond counterpropagating laser pulse (60 times less intense). Alternatively, under poor phase-matching conditions, the counterpropagating light boosts harmonic production by similar contrast through quasiphase matching where out-of-phase emission is suppressed.

  2. Study of optical Laue diffraction

    SciTech Connect

    Chakravarthy, Giridhar E-mail: aloksharan@email.com; Allam, Srinivasa Rao E-mail: aloksharan@email.com; Satyanarayana, S. V. M. E-mail: aloksharan@email.com; Sharan, Alok E-mail: aloksharan@email.com

    2014-10-15

    We present the study of the optical diffraction pattern of one and two-dimensional gratings with defects, designed using desktop pc and printed on OHP sheet using laser printer. Gratings so prepared, using novel low cost technique provides good visual aid in teaching. Diffraction pattern of the monochromatic light (632.8nm) from the grating so designed is similar to that of x-ray diffraction pattern of crystal lattice with point defects in one and two-dimensions. Here both optical and x-ray diffractions are Fraunhofer. The information about the crystalline lattice structure and the defect size can be known.

  3. microARPES and nanoARPES at diffraction-limited light sources: opportunities and performance gains.

    PubMed

    Rotenberg, Eli; Bostwick, Aaron

    2014-09-01

    The scientific opportunities for microARPES and nanoARPES techniques are discussed, and the benefits to these techniques at diffraction-limited light sources are presented, in particular the impact on spectromicroscopic ARPES (angle-resolved photoemission spectroscopy) of upgrading the Advanced Light Source to diffraction-limited performance. The most important consideration is whether the space-charge broadening, impacting the energy and momentum resolution, will limit the possible benefits for ARPES. Calculations of energy broadening due to space-charge effects will be presented over a wide range of parameters, and optimum conditions for ARPES will be discussed. The conclusion is that spectromicroscopic ARPES will greatly benefit from the advent of diffraction-limited light sources; space-charge broadening effects will not be a limiting factor. PMID:25177993

  4. Photonic spatial reformatting of stellar light for diffraction-limited spectroscopy

    NASA Astrophysics Data System (ADS)

    Harris, R. J.; MacLachlan, D. G.; Choudhury, D.; Morris, T. J.; Gendron, E.; Basden, A. G.; Brown, G.; Allington-Smith, J. R.; Thomson, R. R.

    2015-06-01

    The spectral resolution of a dispersive spectrograph is dependent on the width of the entrance slit. This means that astronomical spectrographs trade-off throughput with spectral resolving power. Recently, optical guided-wave transitions known as photonic lanterns have been proposed to circumvent this trade-off, by enabling the efficient reformatting of multimode light into a pseudo-slit which is highly multimode in one axis, but diffraction-limited in the other. Here, we demonstrate the successful reformatting of a telescope point spread function into such a slit using a three-dimensional integrated optical waveguide device, which we name the photonic dicer. Using the CANARY adaptive optics (AO) demonstrator on the William Herschel Telescope, and light centred at 1530 nm with a 160 nm full width at half-maximum, the device shows a transmission of between 10 and 20 per cent depending upon the type of AO correction applied. Most of the loss is due to the overfilling of the input aperture in poor and moderate seeing. Taking this into account, the photonic device itself has a transmission of 57 ± 4 per cent. We show how a fully-optimized device can be used with AO to provide efficient spectroscopy at high spectral resolution.

  5. Combined front and back diffraction gratings for broad band light trapping in thin film solar cell.

    PubMed

    Meng, Xianqin; Drouard, Emmanuel; Gomard, Guillaume; Peretti, Romain; Fave, Alain; Seassal, Christian

    2012-09-10

    In this paper, we present the integration of combined front and back 1D and 2D diffraction gratings with different periods, within thin film photovoltaic solar cells based on crystalline silicon layers. The grating structures have been designed considering both the need for incident light absorption enhancement and the technological feasibility. Long wavelength absorption is increased thanks to the long period (750 nm) back grating, while the incident light reflection is reduced by using a short period (250 nm) front grating. The simulated short circuit current in a solar cell combining a front and a back grating structures with a 1.2 µm thick c-Si layer, together with the back electrode and TCO layers, is increased up to 30.3 mA/cm2, compared to 18.4 mA/cm2 for a reference stack, as simulated using the AM1.5G solar spectrum intensity distribution from 300 nm to 1100 nm, and under normal incidence.

  6. 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.

  7. Light beam diffraction on inhomogeneous holographic photonic PDLC structures under the influence of spatially non-uniform electric field

    NASA Astrophysics Data System (ADS)

    Semkin, A. O.; Sharangovich, S. N.

    2016-08-01

    In this work the theoretical model of two-dimensional Bragg diffraction of quasimonochromatic light beams on amplitude- and phase- inhomogeneous holographic photonic PDLC structures under the impact of spatially non-uniform electric field is proposed. The selfconsistent solutions for the light diffraction on PDLC structure with uniform amplitude and quasi-quadratic profiles are obtained for the case of influence of linearly varying electric field. The possibility to compensate the PDLC structure response inhomogeneity by the impact of non-unifrom external field is shown.

  8. Visible-light photocatalytic degradation of methylene blue with laser-induced Ag/ZnO nanoparticles

    NASA Astrophysics Data System (ADS)

    Whang, Thou-Jen; Hsieh, Mu-Tao; Chen, Huang-Han

    2012-01-01

    The preparation of Ag doped ZnO nanoparticles conducted through the method of laser-induction is presented in this work. The Ag/ZnO nanoparticles attained from various weight percentages of added AgNO3 relative to ZnO were applied under visible-light irradiation for evaluating the heterogeneous photocatalytic degradations of methylene blue (MB) solutions. It was shown that the catalytic behavior of Ag/ZnO nanoparticles in the visible-light range is notably improved through the Ag deposition onto ZnO nanoparticles by the method of laser-induction with a maximum effectiveness of 92% degradation. The properties of the nanoparticles were characterized by the employments of UV-vis spectroscopy (UV-vis), X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), and selected-area electron diffraction (SAED).

  9. A large aperture laser triggered intensified charge coupled device using second-harmonic laser light triggering

    NASA Astrophysics Data System (ADS)

    Yamauchi, Toshihiko; Dimock, Dirck

    1997-06-01

    For application to a ruby laser Thomson scattering system, we have developed a laser triggered intensified charge coupled device (CCD) with 80 mm aperture, two stages of intensification, and 80 ns gating. To improve the dynamic range, the CCD is cooled and read out slowly (1 s). To obtain a good extinction ratio (>1.1×107), the zoom electrode of the first intensifier is gated using a ˜10 kV laser triggered spark gap. The stability of this spark gap has been greatly improved by frequency doubling the laser trigger light.

  10. Planar laser light scattering technique for measurement of nonspherical particles

    NASA Astrophysics Data System (ADS)

    Kim, Hyun Woo; Choi, Man Soo; Jeong, Dae Hwa; Lee, Hyo Hyung

    2004-09-01

    Small particles are one of the biggest sources that cause loss in semiconductor and flat panel display industry. Therefore, it is important to control them during their manufacturing process. To achieve this goal, exact measurement of particles is first required. Laser light scattering is the most widely used technique for diagnosis of particles because it does not disturb flow field and enables real time and spatially resolved analysis. Measurement of nonspherical aggregates comprised of small primary particles is difficult compared with spherical particles because they have very complex morphology. In addition, most researches on aggregates using light scattering are limited to point measurement, which requires much time to inspect large area and is difficult to observe unsteady phenomenon. Motivated by this, we have developed a laser light scattering method for simultaneous measurement of spatial distributions of aggregate size and morphology. Silica aggregates that were generated in Methane/air premixed flame were used as test particles. Multiangular planar light scattering measurement was carried out using a sheet beam of Ar ion laser and an intensified charge coupled device (ICCD) camera as a light source and a detector, respectively. The result was interpreted based on the Rayleigh-Debye-Gans scattering theory for fractal aggregates to obtain the mean radius of gyration and fractal dimension that are the parameters characterizing aggregate size and morphology. The suitability of our new technique was confirmed by experiment using conventional light scattering.

  11. The efficiency of photovoltaic cells exposed to pulsed laser light

    NASA Technical Reports Server (NTRS)

    Lowe, R. A.; Landis, G. A.; Jenkins, P.

    1993-01-01

    Future space missions may use laser power beaming systems with a free electron laser (FEL) to transmit light to a photovoltaic array receiver. To investigate the efficiency of solar cells with pulsed laser light, several types of GaAs, Si, CuInSe2, and GaSb cells were tested with the simulated pulse format of the induction and radio frequency (RF) FEL. The induction pulse format was simulated with an 800-watt average power copper vapor laser and the RF format with a frequency-doubled mode-locked Nd:YAG laser. Averaged current vs bias voltage measurements for each cell were taken at various optical power levels and the efficiency measured at the maximum power point. Experimental results show that the conversion efficiency for the cells tested is highly dependent on cell minority carrier lifetime, the width and frequency of the pulses, load impedance, and the average incident power. Three main effects were found to decrease the efficiency of solar cells exposed to simulated FEL illumination: cell series resistance, LC 'ringing', and output inductance. Improvements in efficiency were achieved by modifying the frequency response of the cell to match the spectral energy content of the laser pulse with external passive components.

  12. Strategies for in situ laser heating in the diamond anvil cell at an X-ray diffraction beamline.

    PubMed

    Petitgirard, Sylvain; Salamat, Ashkan; Beck, Pierre; Weck, Gunnar; Bouvier, Pierre

    2014-01-01

    An overview of several innovations regarding in situ laser-heating techniques in the diamond anvil cell at the high-pressure beamline ID27 of the European Synchrotron Radiation Facility is presented. Pyrometry measurements have been adapted to allow simultaneous double-sided temperature measurements with the installation of two additional online laser systems: a CO2 and a pulsed Nd:YAG laser system. This reiteration of laser-heating advancements at ID27 is designed to pave the way for a new generation of state-of-the-art experiments that demand the need for synchrotron diffraction techniques. Experimental examples are provided for each major development. The capabilities of the double pyrometer have been tested with the Nd:YAG continuous-wave lasers but also in a time-resolved configuration using the nanosecond-pulsed Nd:YAG laser on a Fe sample up to 180 GPa and 2900 K. The combination of time-resolved X-ray diffraction with in situ CO2 laser heating is shown with the crystallization of a high-pressure phase of the naturally found pyrite mineral MnS2 (11 GPa, 1100-1650 K). PMID:24365921

  13. Laser light passage through restored and carious posterior teeth.

    PubMed

    Chandler, N P; Pitt Ford, T R; Monteith, B D

    2014-08-01

    Laser Doppler flowmetry (LDF) has been used to investigate pulpal blood flow as a means of pulp vitality testing. Transmission of laser light from the tooth surface to the pulp space may be influenced by caries and restorations. One hundred and twenty-two first and second molars that had caries into dentine, restorations or significant loss of coronal tissue were sectioned in half axio-bucco-lingually. The two sections were illuminated with a laser from their buccal and lingual aspects 2 mm coronal to the amelocemental junction. Light reaching the pulp space was recorded. Buccal and lingual illumination sites were equally effective for 67 teeth (55%). Buccal sites alone were effective for 35 teeth (29%), despite over one-third of these surfaces being restored or featuring enamel or dentine caries. A lingual position alone was effective for 20 teeth (16%). Caries affected light transmission, but for over half the teeth, the pulp could be illuminated from all four probe positions. No effect was found when the influence of mesial and distal restorations on transmission into the corresponding tooth section was examined. The pulp spaces of most (84%) restored, and carious posterior teeth could be illuminated by laser light from their buccal aspect and these teeth could potentially be vitality tested using LDF.

  14. Rate-equation approach to atomic-laser light statistics

    SciTech Connect

    Chusseau, Laurent; Arnaud, Jacques; Philippe, Fabrice

    2002-11-01

    We consider three- and four-level atomic lasers that are either incoherently (unidirectionally) or coherently (bidirectionally) pumped, the single-mode cavity being resonant with the laser transition. The intracavity Fano factor and the photocurrent spectral density are evaluated on the basis of rate equations. According to that approach, fluctuations are caused by jumps in active and detecting atoms. The algebra is simple. Whenever a comparison is made, the expressions obtained coincide with the previous results. The conditions under which the output light exhibits sub-Poissonian statistics are considered in detail. Analytical results, based on linearization, are verified by comparison with Monte Carlo simulations. An essentially exhaustive investigation of sub-Poissonian light generation by three- and four-level lasers has been performed. Only special forms were reported earlier.

  15. A synchronous strobed laser light sheet for rotor flow visualization

    NASA Astrophysics Data System (ADS)

    Leighty, Bradley D.; Rhodes, David B.; Franke, John M.; Jones, Stephen B.

    1991-05-01

    A synchronous strobed laser light sheet generator was designed and used for flow visualization of a helicopter rotor model. The laser light sheet strobe circuit was designed to allow selectable blade position viewing, strobe duration, and multiple pulses per revolution for rotors having 2 to 9 blades. A slip-sync mode permits slow motion visualization of the flow field over complete rotations of the rotor. The design was tested at NASA Langley Research Center's 14 by 22 foot subsonic tunnel where the flow was seeded with propylene glycol smoke. Between runs, a calibration grid board was placed in the plane of the laser sheet and recorded with the video camera at the position used to record the flow field. The system was used to make 2-dimensional flow field cuts of a four-bladed rotor operating at wind tunnel speeds up to 79.25 meters per second (260 feet per second).

  16. Towards Laser Cooling Trapped Ions with Telecom Light

    NASA Astrophysics Data System (ADS)

    Dungan, Kristina; Becker, Patrick; Donoghue, Liz; Liu, Jackie; Olmschenk, Steven

    2015-05-01

    Quantum information has many potential applications in communication, atomic clocks, and the precision measurement of fundamental constants. Trapped ions are excellent candidates for applications in quantum information because of their isolation from external perturbations, and the precise control afforded by laser cooling and manipulation of the quantum state. For many applications in quantum communication, it would be advantageous to interface ions with telecom light. We present progress towards laser cooling and trapping of doubly-ionized lanthanum, which should require only infrared, telecom-compatible light. Additionally, we present progress on optimization of a second-harmonic generation cavity for laser cooling and trapping barium ions, for future sympathetic cooling experiments. This research is supported by the Army Research Office, Research Corporation for Science Advancement, and Denison University.

  17. Laser Particle Diffraction: A Novel Approach to Quantify In-Situ Suspended Sediment Particle Size Class Concentrations

    NASA Astrophysics Data System (ADS)

    Freeman, G. W.; Hubbart, J. A.; Chinnasamy, P.; Bulliner, E. A.; Schulz, J.

    2010-12-01

    Hydrologic modification exacted by development can variably increase or decreases diffuse pollution loads, and sediment particle class concentrations. For example, larger particle classes may originate primarily from agricultural and localized riparian development or in-stream hydrogeomorphological processes, while smaller particle size class concentrations may increase in urban environments. These distinctions are critical since fine sediments can transport greater quantities of adsorbed chemicals, nutrients and pollutants, fill interstitial spaces of gravel in spawning beds, and detrimentally affect aquatic biota (e.g. invertebrates and fish). Laser Diffraction (LD) instruments measure optical scattering with specially constructed detectors to detect light diffraction effects of particles of individual size classes. The Streamside Laser In-Situ Scattering and Transmissometry (LISST, Sequoia Scientific, Inc) LD instrument was designed for monitoring suspended sediment in shallow rivers, streams, and ponds sensing particle sizes ranging from 1.9 to 387 um (accuracy ± 10 to 20%). Multiple on-going studies in central Missouri, USA are utilizing LD instruments to better understand anthropogenic diffuse sediment pollution. Three LD units were deployed in a central Missouri stream during spring 2010. In an Urban environment, after a single precipitation event the largest particle class bin (356.79 um) comprised almost 50% of the total concentration of suspended sediments in pre-event flow conditions, whereas in the post-precipitation flow event conditions it comprised nearly 44%, a 12.5% difference. The smallest particle class (2.06 um) concentrations in pre and post-precipitation event conditions was 0.8 and 3.4% respectively reflecting more than 450% increased concentration in post flow conditions after a 13.2 mm (0.52 in) precipitation event. During the month of March 2010 average total concentration of sediment (μl/l) in forested, agricultural, and urban

  18. Light source employing laser-produced plasma

    SciTech Connect

    Tao, Yezheng; Tillack, Mark S

    2013-09-17

    A system and a method of generating radiation and/or particle emissions are disclosed. In at least some embodiments, the system includes at least one laser source that generates a first pulse and a second pulse in temporal succession, and a target, where the target (or at least a portion the target) becomes a plasma upon being exposed to the first pulse. The plasma expand after the exposure to the first pulse, the expanded plasma is then exposed to the second pulse, and at least one of a radiation emission and a particle emission occurs after the exposure to the second pulse. In at least some embodiments, the target is a solid piece of material, and/or a time period between the first and second pulses is less than 1 microsecond (e.g., 840 ns).

  19. New method of space debris cleaning based on light negative force: tractor laser

    NASA Astrophysics Data System (ADS)

    Sun, Qiongge; Gao, Long; Li, Chen

    2016-01-01

    This paper presents a new way of space debris removal and protection, that is, using tractor laser, which based on light negative force, to achieve space debris cleaning and shielded. Tractor laser is traceable from the theory of optical tweezers, accompanied with non-diffraction beam. These kind of optical beams have the force named negative force pointing to optical source, this will bring the object along the trajectory of laser beam moving to the optical source. The negative force leads to the new method to convey and sampling the space micro-objects. In this paper, the application of tractor laser in the space debris collection and protection of 1cm is studied. The application of the several tractor beams in the space debris and sample collection is discussed. The proposed method can reduce the requirements of the laser to the satellite platform, and realize the collection of space debris, make the establishment of the space garbage station possible, and help to study the spatial non contact sample transmission and reduce the risk of space missions.

  20. Real-time detection of focal position of workpiece surface during laser processing using diffractive beam samplers

    NASA Astrophysics Data System (ADS)

    Cao, Binh Xuan; Hoang, PhuongLe; Ahn, Sanghoon; Kim, Jeng-o.; Sohn, Hyonkee; Noh, Jiwhan

    2016-11-01

    The real-time fabrication of microgrooves on a curved surface using a laser beam, without preprogramming their shapes into the machining instructions, is a major challenge in laser processing owing to limitations associated with the real-time detection of the focal position. A new approach using a sampled fraction of the beam from a diffractive beam sampler (DBS) is therefore presented in order to overcome this limitation. By considering the sampled fraction of the beam an analysis of the results allows for precise positioning of the specimen for focal-point identification. This allows for the determination of the focus for a broad variety of laser types and laser powers, thereby providing stringent focusing conditions with high numerical apertures. This approach is easy to implement, inexpensive, independent of the roughness or granularity of the workpieces, and more importantly does not require auxiliary lasers and displacement sensors for real-time measurement during the fabrication process.

  1. Coherent diffraction imaging analysis of shape-controlled nanoparticles with focused hard X-ray free-electron laser pulses.

    PubMed

    Takahashi, Yukio; Suzuki, Akihiro; Zettsu, Nobuyuki; Oroguchi, Tomotaka; Takayama, Yuki; Sekiguchi, Yuki; Kobayashi, Amane; Yamamoto, Masaki; Nakasako, Masayoshi

    2013-01-01

    We report the first demonstration of the coherent diffraction imaging analysis of nanoparticles using focused hard X-ray free-electron laser pulses, allowing us to analyze the size distribution of particles as well as the electron density projection of individual particles. We measured 1000 single-shot coherent X-ray diffraction patterns of shape-controlled Ag nanocubes and Au/Ag nanoboxes and estimated the edge length from the speckle size of the coherent diffraction patterns. We then reconstructed the two-dimensional electron density projection with sub-10 nm resolution from selected coherent diffraction patterns. This method enables the simultaneous analysis of the size distribution of synthesized nanoparticles and the structures of particles at nanoscale resolution to address correlations between individual structures of components and the statistical properties in heterogeneous systems such as nanoparticles and cells.

  2. Perovskite Materials for Light-Emitting Diodes and Lasers.

    PubMed

    Veldhuis, Sjoerd A; Boix, Pablo P; Yantara, Natalia; Li, Mingjie; Sum, Tze Chien; Mathews, Nripan; Mhaisalkar, Subodh G

    2016-08-01

    Organic-inorganic hybrid perovskites have cemented their position as an exceptional class of optoelectronic materials thanks to record photovoltaic efficiencies of 22.1%, as well as promising demonstrations of light-emitting diodes, lasers, and light-emitting transistors. Perovskite materials with photoluminescence quantum yields close to 100% and perovskite light-emitting diodes with external quantum efficiencies of 8% and current efficiencies of 43 cd A(-1) have been achieved. Although perovskite light-emitting devices are yet to become industrially relevant, in merely two years these devices have achieved the brightness and efficiencies that organic light-emitting diodes accomplished in two decades. Further advances will rely decisively on the multitude of compositional, structural variants that enable the formation of lower-dimensionality layered and three-dimensional perovskites, nanostructures, charge-transport materials, and device processing with architectural innovations. Here, the rapid advancements in perovskite light-emitting devices and lasers are reviewed. The key challenges in materials development, device fabrication, operational stability are addressed, and an outlook is presented that will address market viability of perovskite light-emitting devices.

  3. Perovskite Materials for Light-Emitting Diodes and Lasers.

    PubMed

    Veldhuis, Sjoerd A; Boix, Pablo P; Yantara, Natalia; Li, Mingjie; Sum, Tze Chien; Mathews, Nripan; Mhaisalkar, Subodh G

    2016-08-01

    Organic-inorganic hybrid perovskites have cemented their position as an exceptional class of optoelectronic materials thanks to record photovoltaic efficiencies of 22.1%, as well as promising demonstrations of light-emitting diodes, lasers, and light-emitting transistors. Perovskite materials with photoluminescence quantum yields close to 100% and perovskite light-emitting diodes with external quantum efficiencies of 8% and current efficiencies of 43 cd A(-1) have been achieved. Although perovskite light-emitting devices are yet to become industrially relevant, in merely two years these devices have achieved the brightness and efficiencies that organic light-emitting diodes accomplished in two decades. Further advances will rely decisively on the multitude of compositional, structural variants that enable the formation of lower-dimensionality layered and three-dimensional perovskites, nanostructures, charge-transport materials, and device processing with architectural innovations. Here, the rapid advancements in perovskite light-emitting devices and lasers are reviewed. The key challenges in materials development, device fabrication, operational stability are addressed, and an outlook is presented that will address market viability of perovskite light-emitting devices. PMID:27214091

  4. Fifth-Generation Free-Electron Laser Light Sources

    SciTech Connect

    Pellegrini, Claudio

    2011-03-02

    During the past few years, the Linac Coherent Light Source (LCLS) and the Free-Electron Laser in Hamburg (FLASH) have demonstrated the outstanding capability of free-electron lasers (FELs) as sources of coherent radiation in the soft and hard x-ray region. The high intensity, tens of GW, short pulses (few to less than 100 femtoseconds, and the unique transverse coherence properties are opening a new window to study the structure and dynamics of atomic and molecular systems. The LCLS, FLASH, and the other FELs now under construction are only the beginning of the development of these light sources. The next generations will reach new levels of performance: terawatt, atto-second, ultra-small line-width, high repetition rate, full longitudinal and transverse coherence. These future developments and the R&D needed to successfully build and operate the next generation of FEL light sources will be discussed.

  5. Probing liquid surface waves, liquid properties and liquid films with light diffraction

    NASA Astrophysics Data System (ADS)

    Barik, Tarun Kr; Chaudhuri, Partha Roy; Roy, Anushree; Kar, Sayan

    2006-06-01

    Surface waves on liquids act as a dynamical phase grating for incident light. In this paper, we revisit the classical method of probing such waves (wavelengths of the order of mm) as well as inherent properties of liquids and liquid films on liquids, using optical diffraction. A combination of simulation and experiment is proposed to trace out the surface wave profiles in various situations (e.g. for one or more vertical, slightly immersed, electrically driven exciters). Subsequently, the surface tension and the spatial damping coefficient (related to viscosity) of a variety of liquids are measured carefully in order to gauge the efficiency of measuring liquid properties using this optical probe. The final set of results deal with liquid films where dispersion relations, surface and interface modes, interfacial tension and related issues are investigated in some detail, both theoretically and experimentally. On the whole, our observations and analysis seem to support the claim that this simple, low cost apparatus is capable of providing a wealth of information on liquids and liquid surface waves in a non-destructive way.

  6. High throughput imaging of blood smears using white light diffraction phase microscopy

    NASA Astrophysics Data System (ADS)

    Majeed, Hassaan; Kandel, Mikhail E.; Bhaduri, Basanta; Han, Kevin; Luo, Zelun; Tangella, Krishnarao; Popescu, Gabriel

    2015-03-01

    While automated blood cell counters have made great progress in detecting abnormalities in blood, the lack of specificity for a particular disease, limited information on single cell morphology and intrinsic uncertainly due to high throughput in these instruments often necessitates detailed inspection in the form of a peripheral blood smear. Such tests are relatively time consuming and frequently rely on medical professionals tally counting specific cell types. These assays rely on the contrast generated by chemical stains, with the signal intensity strongly related to staining and preparation techniques, frustrating machine learning algorithms that require consistent quantities to denote the features in question. Instead we opt to use quantitative phase imaging, understanding that the resulting image is entirely due to the structure (intrinsic contrast) rather than the complex interplay of stain and sample. We present here our first steps to automate peripheral blood smear scanning, in particular a method to generate the quantitative phase image of an entire blood smear at high throughput using white light diffraction phase microscopy (wDPM), a single shot and common path interferometric imaging technique.

  7. Cryogenic coherent X-ray diffraction imaging of biological samples at SACLA: a correlative approach with cryo-electron and light microscopy.

    PubMed

    Takayama, Yuki; Yonekura, Koji

    2016-03-01

    Coherent X-ray diffraction imaging at cryogenic temperature (cryo-CXDI) allows the analysis of internal structures of unstained, non-crystalline, whole biological samples in micrometre to sub-micrometre dimensions. Targets include cells and cell organelles. This approach involves preparing frozen-hydrated samples under controlled humidity, transferring the samples to a cryo-stage inside a vacuum chamber of a diffractometer, and then exposing the samples to coherent X-rays. Since 2012, cryo-coherent diffraction imaging (CDI) experiments have been carried out with the X-ray free-electron laser (XFEL) at the SPring-8 Ångstrom Compact free-electron LAser (SACLA) facility in Japan. Complementary use of cryo-electron microscopy and/or light microscopy is highly beneficial for both pre-checking samples and studying the integrity or nature of the sample. This article reports the authors' experience in cryo-XFEL-CDI of biological cells and organelles at SACLA, and describes an attempt towards reliable and higher-resolution reconstructions, including signal enhancement with strong scatterers and Patterson-search phasing. PMID:26919369

  8. Cryogenic coherent X-ray diffraction imaging of biological samples at SACLA: a correlative approach with cryo-electron and light microscopy.

    PubMed

    Takayama, Yuki; Yonekura, Koji

    2016-03-01

    Coherent X-ray diffraction imaging at cryogenic temperature (cryo-CXDI) allows the analysis of internal structures of unstained, non-crystalline, whole biological samples in micrometre to sub-micrometre dimensions. Targets include cells and cell organelles. This approach involves preparing frozen-hydrated samples under controlled humidity, transferring the samples to a cryo-stage inside a vacuum chamber of a diffractometer, and then exposing the samples to coherent X-rays. Since 2012, cryo-coherent diffraction imaging (CDI) experiments have been carried out with the X-ray free-electron laser (XFEL) at the SPring-8 Ångstrom Compact free-electron LAser (SACLA) facility in Japan. Complementary use of cryo-electron microscopy and/or light microscopy is highly beneficial for both pre-checking samples and studying the integrity or nature of the sample. This article reports the authors' experience in cryo-XFEL-CDI of biological cells and organelles at SACLA, and describes an attempt towards reliable and higher-resolution reconstructions, including signal enhancement with strong scatterers and Patterson-search phasing.

  9. Single-frequency blue light generation by single-pass sum-frequency generation in a coupled ring cavity tapered laser

    NASA Astrophysics Data System (ADS)

    Bjarlin Jensen, Ole; Michael Petersen, Paul

    2013-09-01

    A generic approach for generation of tunable single frequency light is presented. 340 mW of near diffraction limited, single-frequency, and tunable blue light around 459 nm is generated by sum-frequency generation (SFG) between two tunable tapered diode lasers. One diode laser is operated in a ring cavity and another tapered diode laser is single-passed through a nonlinear crystal which is contained in the coupled ring cavity. Using this method, the single-pass conversion efficiency is more than 25%. In contrast to SFG in an external cavity, the system is entirely self-stabilized with no electronic locking.

  10. Optical fiber diameter measurement by the diffraction method with digital processing of the light scattering indicatrix

    NASA Astrophysics Data System (ADS)

    Kokodii, N. G.; Natarova, A. O.

    2016-07-01

    Relations between the position of the first diffraction minima and the fiber diameter are derived based on the solution of the problem of electromagnetic wave diffraction on a transparent fiber with a circular cross section. The obtained formulas are used to measure the fiber diameter. The diffraction pattern is recorded with a digital camera. The obtained image is digitally processed to determine the positions of the first two scattering indicatrix minima.

  11. Laser, light, and energy devices for cellulite and lipodystrophy.

    PubMed

    Peterson, Jennifer D; Goldman, Mitchel P

    2011-07-01

    Cellulite affects all races, and it is estimated that 85% of women older than 20 years have some degree of cellulite. Many currently accepted cellulite therapies target deficiencies in lymphatic drainage and microvascular circulation. Devices using radiofrequency, laser, and light-based energies, alone or in combination and coupled frequently with tissue manipulation, are available for improving cellulite. Laser assisted liposuction may improve cellulite appearance. Although improvement using these devices is temporary, it may last several months. Patients who want smoother skin with less visible cellulite can undergo a series of treatments and then return for additional treatments as necessary.

  12. Let there be light--the laser in dentistry.

    PubMed

    Mercer, C

    1992-06-20

    A damp and dull London day in March somewhat contradicted the title of the meeting of the Odontology Section of the RSM, Let there be light--the laser in dentistry, but there was no doubt, once inside, that the organisers had, with perfect timing, caught the interest of the profession as a Barnes Room packed to capacity was greeted by the president of the section, Margaret Seward. Rather apologetically, she confessed that the film Goldfinger was unavailable, but promised us equal fascination with a galaxy of international experts to guide us through a maze of new developments in laser dentistry.

  13. Critical Evaluation of Particle Size Distribution Models Using Soil Data Obtained with a Laser Diffraction Method

    PubMed Central

    Weipeng, Wang; Jianli, Liu; Bingzi, Zhao; Jiabao, Zhang; Xiaopeng, Li; Yifan, Yan

    2015-01-01

    Mathematical descriptions of classical particle size distribution (PSD) data are often used to estimate soil hydraulic properties. Laser diffraction methods (LDM) now provide more detailed PSD measurements, but deriving a function to characterize the entire range of particle sizes is a major challenge. The aim of this study was to compare the performance of eighteen PSD functions for fitting LDM data sets from a wide range of soil textures. These models include five lognormal models, five logistic models, four van Genuchten models, two Fredlund models, a logarithmic model, and an Andersson model. The fits were evaluated using Akaike’s information criterion (AIC), adjusted R2, and root-mean-square error (RMSE). The results indicated that the Fredlund models (FRED3 and FRED4) had the best performance for most of the soils studied, followed by one logistic growth function extension model (MLOG3) and three lognormal models (ONLG3, ORLG3, and SHCA3). The performance of most PSD models was better for soils with higher silt content and poorer for soils with higher clay and sand content. The FRED4 model best described the PSD of clay, silty clay, clay loam, silty clay loam, silty loam, loam, and sandy loam, whereas FRED3, MLOG3, ONLG3, ORLG3, and SHCA3 showed better performance for most soils studied. PMID:25927441

  14. Response characteristics of laser diffraction particle size analyzers - Optical sample volume extent and lens effects

    NASA Technical Reports Server (NTRS)

    Hirleman, E. D.; Oechsle, V.; Chigier, N. A.

    1984-01-01

    The response characteristics of laser diffraction particle sizing instruments were studied theoretically and experimentally. In particular, the extent of optical sample volume and the effects of receiving lens properties were investigated in detail. The experimental work was performed with a particle size analyzer using a calibration reticle containing a two-dimensional array of opaque circular disks on a glass substrate. The calibration slide simulated the forward-scattering characteristics of a Rosin-Rammler droplet size distribution. The reticle was analyzed with collection lenses of 63 mm, 100 mm, and 300 mm focal lengths using scattering inversion software that determined best-fit Rosin-Rammler size distribution parameters. The data differed from the predicted response for the reticle by about 10 percent. A set of calibration factor for the detector elements was determined that corrected for the nonideal response of the instrument. The response of the instrument was also measured as a function of reticle position, and the results confirmed a theoretical optical sample volume model presented here.

  15. X-ray laser diffraction for structure determination of the rhodopsin-arrestin complex

    DOE PAGESBeta

    Zhou, X. Edward; Gao, Xiang; Barty, Anton; Kang, Yanyong; He, Yuanzheng; Liu, Wei; Ishchenko, Andrii; White, Thomas A.; Yefanov, Oleksandr; Han, Gye Won; et al

    2016-04-12

    Here, serial femtosecond X-ray crystallography (SFX) using an X-ray free electron laser (XFEL) is a recent advancement in structural biology for solving crystal structures of challenging membrane proteins, including G-protein coupled receptors (GPCRs), which often only produce microcrystals. An XFEL delivers highly intense X-ray pulses of femtosecond duration short enough to enable the collection of single diffraction images before significant radiation damage to crystals sets in. Here we report the deposition of the XFEL data and provide further details on crystallization, XFEL data collection and analysis, structure determination, and the validation of the structural model. The rhodopsin-arrestin crystal structure solvedmore » with SFX represents the first near-atomic resolution structure of a GPCR-arrestin complex, provides structural insights into understanding of arrestin-mediated GPCR signaling, and demonstrates the great potential of this SFX-XFEL technology for accelerating crystal structure determination of challenging proteins and protein complexes.« less

  16. Multilevel diffractive optical element manufacture by excimer laser ablation and halftone masks

    NASA Astrophysics Data System (ADS)

    Quentel, Francois; Fieret, Jim; Holmes, Andrew S.; Paineau, Sylvain

    2001-06-01

    A novel method is presented to manufacture multilevel diffractive optical elements (DOEs) in polymer by single- step KrF excimer laser ablation using a halftone mask. The DOEs have a typical pixel dimension of 5 micrometers and are up to 512 by 512 pixels in size. The DOEs presented are Fresnel lenses and Fourier computer generated holograms, calculated by means of a conventional iterative Fourier transform algorithm. The halftone mask is built up as an array of 5 micrometers -square pixels, each containing a rectangular or L- shaped window on an opaque background. The mask is imaged onto the polymer with a 5x, 0.13 NA reduction lens. The pixels are not resolved by the lens, so they behave simply as attenuators, allowing spatial variation of the ablation rate via the window size. The advantages of halftone mask technology over other methods, such as pixel-by-pixel ablation and multi-mask overlay, are that it is very fast regardless of DOE size, and that no high-precision motion stages and alignment are required. The challenges are that the halftone mask is specific to the etch curve of the polymer used, that precise calibration of each grey-level is required, and that the halftone mask must be calculated specifically for the imaging lens used. This paper describes the design procedures for multilevel DOEs and halftone masks, the calibration of the various levels, and some preliminary DOE test results.

  17. Stimulation of the cochlea using green laser light

    NASA Astrophysics Data System (ADS)

    Wenzel, G. I.; Balster, S.; Lim, H. H.; Zhang, K.; Reich, U.; Lubatschowski, H.; Ertmer, W.; Lenarz, T.; Reuter, G.

    2009-02-01

    The success of conventional hearing aids and electrical cochlear implants have generally been limited to hearing in quiet situations, in part due to a lack of localized (i.e., frequency specificity) sensorineural activation and subsequent impaired speech discrimination in noise. Laser light is a source of energy that can be focused in a controlled manner and may provide more localized activation of the inner ear, the cochlea. Compound action potentials have been elicited using 2.12 µm laser pulses through activation of auditory nerve fibers (Izzo et al. 2006). Laser stimulation (813 nm) of the cochlea has shown to induce basilar membrane motion and cochlear microphonic potentials (Fridberger et al. 2006). We sought to assess if visible light (green, 532 nm, 10 ns pulses) could be used to consistently activate the cochlea. The laser parameters were selected based on our initial attempt to induce an optoacoustic effect as the energy transfer mechanism to the cochlea. Click evoked auditory brainstem responses (AABRs) were recorded preoperatively in ketamine-anesthetized guinea pigs to confirm normal hearing. The bulla and then the cochlea were exposed. Optically evoked ABRs (OABR) were recorded in response to laser stimulation with a 50 µm optical fiber (532 nm, 10 ns pulses, 500 repetitions, 10 pulses/s; Nd:YAG laser) at the round window (RW) directed towards the basilar membrane (BM). OABRs similar in morphology to acoustically evoked ABRs, except for shorter latencies, were obtained for stimulation through the RW with energy levels between 1.7-30 µJ/pulse. The OABRs increased with increasing energy level reaching a saturation level around 13-15 µJ/pulse. Furthermore the responses remained consistent across stimulation over time, including stimulation at 13 µJ/pulse for over 30 minutes, indicating minimal or no damage within the cochlea with this type of laser stimulation. Overall we have demonstrated that laser light stimulation with 532 nm has

  18. The high frequency characteristics of laser reflection and visible light during solid state disk laser welding

    NASA Astrophysics Data System (ADS)

    Gao, Xiangdong; You, Deyong; Katayama, Seiji

    2015-07-01

    Optical properties are related to weld quality during laser welding. Visible light radiation generated from optical-induced plasma and laser reflection is considered a key element reflecting weld quality. An in-depth analysis of the high-frequency component of optical signals is conducted. A combination of a photoelectric sensor and an optical filter helped to obtain visible light reflection and laser reflection in the welding process. Two groups of optical signals were sampled at a high sampling rate (250 kHz) using an oscilloscope. Frequencies in the ranges 1-10 kHz and 10-125 kHz were investigated respectively. Experimental results showed that there was an obvious correlation between the high-frequency signal and the laser power, while the high-frequency signal was not sensitive to changes in welding speed. In particular, when the defocus position was changed, only a high frequency of the visible light signal was observed, while the high frequency of the laser reflection signal remained unchanged. The basic correlation between optical features and welding status during the laser welding process is specified, which helps to provide a new research focus for investigating the stability of welding status.

  19. Degeneration of Fraunhofer diffraction on bacterial colonies due to their light focusing properties examined in the digital holographic microscope system.

    PubMed

    Buzalewicz, Igor; Liżewski, Kamil; Kujawińska, Małgorzata; Podbielska, Halina

    2013-11-01

    The degeneration of Fraunhofer diffraction conditions in the optical system with converging spherical wave illumination for bacteria species identification based on diffraction patterns is analyzed by digital holographic methods. The obtained results have shown that the colonies of analyzed bacteria species act as biological lenses with the time-dependent light focusing properties, which are characterized and monitored by means of phase retrieval from sequentially captured digital holograms. This significantly affects the location of Fraunhofer patterns observation plane, which is continuously shifted across optical axis in time.

  20. Design of fiber optic probes for laser light scattering

    NASA Technical Reports Server (NTRS)

    Dhadwal, Harbans S.; Chu, Benjamin

    1989-01-01

    A quantitative analysis is presented of the role of optical fibers in laser light scattering. Design of a general fiber optic/microlens probe by means of ray tracing is described. Several different geometries employing an optical fiber of the type used in lightwave communications and a graded index microlens are considered. Experimental results using a nonimaging fiber optic detector probe show that due to geometrical limitations of single mode fibers, a probe using a multimode optical fiber has better performance, for both static and dynamic measurements of the scattered light intensity, compared with a probe using a single mode fiber. Fiber optic detector probes are shown to be more efficient at data collection when compared with conventional approaches to measurements of the scattered laser light. Integration of fiber optic detector probes into a fiber optic spectrometer offers considerable miniaturization of conventional light scattering spectrometers, which can be made arbitrarily small. In addition static and dynamic measurements of scattered light can be made within the scattering cell and consequently very close to the scattering center.

  1. X-Ray Diffraction from Isolated and Strongly Aligned Gas-Phase Molecules with a Free-Electron Laser

    NASA Astrophysics Data System (ADS)

    Küpper, Jochen; Stern, Stephan; Holmegaard, Lotte; Filsinger, Frank; Rouzée, Arnaud; Rudenko, Artem; Johnsson, Per; Martin, Andrew V.; Adolph, Marcus; Aquila, Andrew; Bajt, Saša; Barty, Anton; Bostedt, Christoph; Bozek, John; Caleman, Carl; Coffee, Ryan; Coppola, Nicola; Delmas, Tjark; Epp, Sascha; Erk, Benjamin; Foucar, Lutz; Gorkhover, Tais; Gumprecht, Lars; Hartmann, Andreas; Hartmann, Robert; Hauser, Günter; Holl, Peter; Hömke, Andre; Kimmel, Nils; Krasniqi, Faton; Kühnel, Kai-Uwe; Maurer, Jochen; Messerschmidt, Marc; Moshammer, Robert; Reich, Christian; Rudek, Benedikt; Santra, Robin; Schlichting, Ilme; Schmidt, Carlo; Schorb, Sebastian; Schulz, Joachim; Soltau, Heike; Spence, John C. H.; Starodub, Dmitri; Strüder, Lothar; Thøgersen, Jan; Vrakking, Marc J. J.; Weidenspointner, Georg; White, Thomas A.; Wunderer, Cornelia; Meijer, Gerard; Ullrich, Joachim; Stapelfeldt, Henrik; Rolles, Daniel; Chapman, Henry N.

    2014-02-01

    We report experimental results on x-ray diffraction of quantum-state-selected and strongly aligned ensembles of the prototypical asymmetric rotor molecule 2,5-diiodobenzonitrile using the Linac Coherent Light Source. The experiments demonstrate first steps toward a new approach to diffractive imaging of distinct structures of individual, isolated gas-phase molecules. We confirm several key ingredients of single molecule diffraction experiments: the abilities to detect and count individual scattered x-ray photons in single shot diffraction data, to deliver state-selected, e.g., structural-isomer-selected, ensembles of molecules to the x-ray interaction volume, and to strongly align the scattering molecules. Our approach, using ultrashort x-ray pulses, is suitable to study ultrafast dynamics of isolated molecules.

  2. Laser-activated remote phosphor light engine for projection applications

    NASA Astrophysics Data System (ADS)

    Daniels, Martin; Mehl, Oliver; Hartwig, Ulrich

    2015-09-01

    Recent developments in blue emitting laser diodes enable attractive solutions in projection applications using phosphors for efficient light conversion with very high luminance levels. Various commercially available projectors incorporating this technology have entered the market in the past years. While luminous flux levels are still comparable to lamp-based systems, lifetime expectations of classical lamp systems are exceeded by far. OSRAM GmbH has been exploring this technology for several years and has introduced the PHASER® brand name (Phosphor + laser). State-of-the-art is a rotating phosphor wheel excited by blue laser diodes to deliver the necessary primary colors, either sequentially for single-imager projection engines, or simultaneously for 3-panel systems. The PHASER® technology enables flux and luminance scaling, which allows for smaller imagers and therefore cost-efficient projection solutions. The resulting overall efficiency and ANSI lumen specification at the projection screen of these systems is significantly determined by the target color gamut and the light transmission efficiency of the projection system. With increasing power and flux level demand, thermal issues, especially phosphor conversion related, dominate the opto-mechanical system design requirements. These flux levels are a great challenge for all components of an SSL-projection system (SSL:solid-state lighting). OSRAḾs PHASER® light engine platform is constantly expanded towards higher luminous flux levels as well as higher luminance levels for various applications. Recent experiments employ blue laser pump powers of multiple 100 Watts to excite various phosphors resulting in luminous flux levels of more than 40 klm.

  3. Development of a versatile laser light scattering instrument

    NASA Technical Reports Server (NTRS)

    Meyer, William V.; Ansari, Rafat R.

    1992-01-01

    NASA Lewis Research Center is providing and coordinating the technology for placing a compact Laser Light Scattering (LLS) instrument in a microgravity environment. This will be accomplished by defining and assessing user requirements for microgravity experiments, coordinating needed technological developments, and filling technical gaps. This effort is striving to brassboard and evaluate a miniature multi-angle LLS instrument. The progress of the program is reported.

  4. The light-matter interaction of a single semiconducting AlGaN nanowire and noble metal Au nanoparticles in the sub-diffraction limit.

    PubMed

    Sivadasan, A K; Madapu, Kishore K; Dhara, Sandip

    2016-08-24

    Near field scanning optical microscopy (NSOM) is not only a tool for imaging of sub-diffraction limited objects but also a prominent characteristic tool for understanding the intrinsic properties of nanostructures. In order to understand light-matter interactions in the near field regime using a NSOM technique with an excitation of 532 nm (2.33 eV), we selected an isolated single semiconducting AlGaN nanowire (NW) of diameter ∼120 nm grown via a vapor liquid solid (VLS) mechanism along with a metallic Au nanoparticle (NP) catalyst. The role of electronic transitions from different native defect related energy states of AlGaN is discussed in understanding the NSOM images for the semiconducting NW. The effect of strong surface plasmon resonance absorption of an excitation laser on the NSOM images for Au NPs, involved in the VLS growth mechanism of NWs, is also observed. PMID:27511614

  5. The light-matter interaction of a single semiconducting AlGaN nanowire and noble metal Au nanoparticles in the sub-diffraction limit.

    PubMed

    Sivadasan, A K; Madapu, Kishore K; Dhara, Sandip

    2016-08-24

    Near field scanning optical microscopy (NSOM) is not only a tool for imaging of sub-diffraction limited objects but also a prominent characteristic tool for understanding the intrinsic properties of nanostructures. In order to understand light-matter interactions in the near field regime using a NSOM technique with an excitation of 532 nm (2.33 eV), we selected an isolated single semiconducting AlGaN nanowire (NW) of diameter ∼120 nm grown via a vapor liquid solid (VLS) mechanism along with a metallic Au nanoparticle (NP) catalyst. The role of electronic transitions from different native defect related energy states of AlGaN is discussed in understanding the NSOM images for the semiconducting NW. The effect of strong surface plasmon resonance absorption of an excitation laser on the NSOM images for Au NPs, involved in the VLS growth mechanism of NWs, is also observed.

  6. Coherent diffraction of single Rice Dwarf virus particles using hard X-rays at the Linac Coherent Light Source.

    PubMed

    Munke, Anna; Andreasson, Jakob; Aquila, Andrew; Awel, Salah; Ayyer, Kartik; Barty, Anton; Bean, Richard J; Berntsen, Peter; Bielecki, Johan; Boutet, Sébastien; Bucher, Maximilian; Chapman, Henry N; Daurer, Benedikt J; DeMirci, Hasan; Elser, Veit; Fromme, Petra; Hajdu, Janos; Hantke, Max F; Higashiura, Akifumi; Hogue, Brenda G; Hosseinizadeh, Ahmad; Kim, Yoonhee; Kirian, Richard A; Reddy, Hemanth K N; Lan, Ti-Yen; Larsson, Daniel S D; Liu, Haiguang; Loh, N Duane; Maia, Filipe R N C; Mancuso, Adrian P; Mühlig, Kerstin; Nakagawa, Atsushi; Nam, Daewoong; Nelson, Garrett; Nettelblad, Carl; Okamoto, Kenta; Ourmazd, Abbas; Rose, Max; van der Schot, Gijs; Schwander, Peter; Seibert, M Marvin; Sellberg, Jonas A; Sierra, Raymond G; Song, Changyong; Svenda, Martin; Timneanu, Nicusor; Vartanyants, Ivan A; Westphal, Daniel; Wiedorn, Max O; Williams, Garth J; Xavier, Paulraj Lourdu; Yoon, Chun Hong; Zook, James

    2016-01-01

    Single particle diffractive imaging data from Rice Dwarf Virus (RDV) were recorded using the Coherent X-ray Imaging (CXI) instrument at the Linac Coherent Light Source (LCLS). RDV was chosen as it is a well-characterized model system, useful for proof-of-principle experiments, system optimization and algorithm development. RDV, an icosahedral virus of about 70 nm in diameter, was aerosolized and injected into the approximately 0.1 μm diameter focused hard X-ray beam at the CXI instrument of LCLS. Diffraction patterns from RDV with signal to 5.9 Ångström were recorded. The diffraction data are available through the Coherent X-ray Imaging Data Bank (CXIDB) as a resource for algorithm development, the contents of which are described here.

  7. Coherent diffraction of single Rice Dwarf virus particles using hard X-rays at the Linac Coherent Light Source.

    PubMed

    Munke, Anna; Andreasson, Jakob; Aquila, Andrew; Awel, Salah; Ayyer, Kartik; Barty, Anton; Bean, Richard J; Berntsen, Peter; Bielecki, Johan; Boutet, Sébastien; Bucher, Maximilian; Chapman, Henry N; Daurer, Benedikt J; DeMirci, Hasan; Elser, Veit; Fromme, Petra; Hajdu, Janos; Hantke, Max F; Higashiura, Akifumi; Hogue, Brenda G; Hosseinizadeh, Ahmad; Kim, Yoonhee; Kirian, Richard A; Reddy, Hemanth K N; Lan, Ti-Yen; Larsson, Daniel S D; Liu, Haiguang; Loh, N Duane; Maia, Filipe R N C; Mancuso, Adrian P; Mühlig, Kerstin; Nakagawa, Atsushi; Nam, Daewoong; Nelson, Garrett; Nettelblad, Carl; Okamoto, Kenta; Ourmazd, Abbas; Rose, Max; van der Schot, Gijs; Schwander, Peter; Seibert, M Marvin; Sellberg, Jonas A; Sierra, Raymond G; Song, Changyong; Svenda, Martin; Timneanu, Nicusor; Vartanyants, Ivan A; Westphal, Daniel; Wiedorn, Max O; Williams, Garth J; Xavier, Paulraj Lourdu; Yoon, Chun Hong; Zook, James

    2016-01-01

    Single particle diffractive imaging data from Rice Dwarf Virus (RDV) were recorded using the Coherent X-ray Imaging (CXI) instrument at the Linac Coherent Light Source (LCLS). RDV was chosen as it is a well-characterized model system, useful for proof-of-principle experiments, system optimization and algorithm development. RDV, an icosahedral virus of about 70 nm in diameter, was aerosolized and injected into the approximately 0.1 μm diameter focused hard X-ray beam at the CXI instrument of LCLS. Diffraction patterns from RDV with signal to 5.9 Ångström were recorded. The diffraction data are available through the Coherent X-ray Imaging Data Bank (CXIDB) as a resource for algorithm development, the contents of which are described here. PMID:27478984

  8. Crystallization and preliminary X-ray diffraction analysis of the peripheral light-harvesting complex LH2 from Marichromatium purpuratum.

    PubMed

    Cranston, Laura J; Roszak, Aleksander W; Cogdell, Richard J

    2014-06-01

    LH2 from the purple photosynthetic bacterium Marichromatium (formerly known as Chromatium) purpuratum is an integral membrane pigment-protein complex that is involved in harvesting light energy and transferring it to the LH1-RC `core' complex. The purified LH2 complex was crystallized using the sitting-drop vapour-diffusion method at 294 K. The crystals diffracted to a resolution of 6 Å using synchrotron radiation and belonged to the tetragonal space group I4, with unit-cell parameters a=b=109.36, c=80.45 Å. The data appeared to be twinned, producing apparent diffraction symmetry I422. The tetragonal symmetry of the unit cell and diffraction for the crystals of the LH2 complex from this species reveal that this complex is an octamer.

  9. Crystallization and preliminary X-ray diffraction analysis of the peripheral light-harvesting complex LH2 from Marichromatium purpuratum

    PubMed Central

    Cranston, Laura J.; Roszak, Aleksander W.; Cogdell, Richard J.

    2014-01-01

    LH2 from the purple photosynthetic bacterium Marichromatium (formerly known as Chromatium) purpuratum is an integral membrane pigment–protein complex that is involved in harvesting light energy and transferring it to the LH1–RC ‘core’ complex. The purified LH2 complex was crystallized using the sitting-drop vapour-diffusion method at 294 K. The crystals diffracted to a resolution of 6 Å using synchrotron radiation and belonged to the tetragonal space group I4, with unit-cell parameters a = b = 109.36, c = 80.45 Å. The data appeared to be twinned, producing apparent diffraction symmetry I422. The tetragonal symmetry of the unit cell and diffraction for the crystals of the LH2 complex from this species reveal that this complex is an octamer. PMID:24915099

  10. Coherent diffraction of single Rice Dwarf virus particles using hard X-rays at the Linac Coherent Light Source

    PubMed Central

    Munke, Anna; Andreasson, Jakob; Aquila, Andrew; Awel, Salah; Ayyer, Kartik; Barty, Anton; Bean, Richard J.; Berntsen, Peter; Bielecki, Johan; Boutet, Sébastien; Bucher, Maximilian; Chapman, Henry N.; Daurer, Benedikt J.; DeMirci, Hasan; Elser, Veit; Fromme, Petra; Hajdu, Janos; Hantke, Max F.; Higashiura, Akifumi; Hogue, Brenda G.; Hosseinizadeh, Ahmad; Kim, Yoonhee; Kirian, Richard A.; Reddy, Hemanth K.N.; Lan, Ti-Yen; Larsson, Daniel S.D.; Liu, Haiguang; Loh, N. Duane; Maia, Filipe R.N.C.; Mancuso, Adrian P.; Mühlig, Kerstin; Nakagawa, Atsushi; Nam, Daewoong; Nelson, Garrett; Nettelblad, Carl; Okamoto, Kenta; Ourmazd, Abbas; Rose, Max; van der Schot, Gijs; Schwander, Peter; Seibert, M. Marvin; Sellberg, Jonas A.; Sierra, Raymond G.; Song, Changyong; Svenda, Martin; Timneanu, Nicusor; Vartanyants, Ivan A.; Westphal, Daniel; Wiedorn, Max O.; Williams, Garth J.; Xavier, Paulraj Lourdu; Yoon, Chun Hong; Zook, James

    2016-01-01

    Single particle diffractive imaging data from Rice Dwarf Virus (RDV) were recorded using the Coherent X-ray Imaging (CXI) instrument at the Linac Coherent Light Source (LCLS). RDV was chosen as it is a well-characterized model system, useful for proof-of-principle experiments, system optimization and algorithm development. RDV, an icosahedral virus of about 70 nm in diameter, was aerosolized and injected into the approximately 0.1 μm diameter focused hard X-ray beam at the CXI instrument of LCLS. Diffraction patterns from RDV with signal to 5.9 Ångström were recorded. The diffraction data are available through the Coherent X-ray Imaging Data Bank (CXIDB) as a resource for algorithm development, the contents of which are described here. PMID:27478984

  11. Rietveld X-ray diffraction analysis of nanostructured rutile films of titania prepared by pulsed laser deposition

    SciTech Connect

    Murugesan, S.; Kuppusami, P.; Mohandas, E.

    2010-01-15

    Rietveld powder X-ray diffraction analysis of the rutile films of titanium oxide prepared by pulsed laser deposition was carried out. The crystallite size increased with increase of substrate temperature, while the strain showed a reverse trend. The films synthesized at temperature {>=}573 K showed that the crystal structure was almost close to that of bulk rutile structure. The influence of the substrate temperature on the lattice parameters and oxygen coordinates were also studied in the present work.

  12. Three-dimensional coherent diffraction imaging of Mie-scattering spheres by laser single-orientation measurement

    NASA Astrophysics Data System (ADS)

    Zhang, Jian; Fan, Jia-Dong; Zhang, Jian-Hua; Sun, Zhi-Bin; Huang, Qing-Jie; Jiang, Huai-Dong

    2015-09-01

    Three-dimensional imaging with single orientation is a potential and novel technique. We successfully demonstrate that three-dimensional (3D) structure can be determined by a single orientation diffraction measurement for a phase object of double-layer Mie-scattering silica spheres on a Si3N4 membrane. Coherent diffraction pattern at high numerical aperture was acquired with an optical laser, and the oversampled pattern was projected from a planar detector onto the Ewald sphere. The double-layered spheres are reconstructed from the spherical diffraction pattern and a 2D curvature-corrected pattern, which improve convergence speed and stability of reconstruction. Project supported by the Major State Basic Research Development Program of China (Grant No. 2014CB910401) and the National Natural Science Foundation of China (Grant Nos. 31430031, 21390414, and U1332118).

  13. Micromachining of polydimethylsiloxane induced by laser plasma EUV light

    NASA Astrophysics Data System (ADS)

    Torii, S.; Makimura, T.; Okazaki, K.; Nakamura, D.; Takahashi, A.; Okada, T.; Niino, H.; Murakami, K.

    2011-06-01

    Polydimethylsiloxane (PDMS) is fundamental materials in the field of biotechnology. Because of its biocompatibility, microfabricated PDMS sheets are applied to micro-reactors and microchips for cell culture. Conventionally, the microstructures were fabricated by means of cast or imprint using molds, however it is difficult to fabricate the structures at high aspect ratios such as through-holes/vertical channels. The fabrication of the high-aspect structures would enable us to stack sheets to realize 3D fluidic circuits. In order to achieve the micromachining, direct photo-ablation by short wavelength light is promising. In the previous works, we investigated ablation of transparent materials such as silica glass and poly(methyl methacrylate) induced by irradiation with laser plasma EUV light. We achieved smooth and fine nanomachining. In this work, we applied our technique to PDMS micromachining. We condensed the EUV light onto PDMS surfaces at high power density up to 108 W/cm2 using a Au coated ellipsoidal mirror. We found that PDMS sheet was ablated at a rate up to 440 nm/shot. It should be emphasized that through hole with a diameter of 1 μm was fabricated in a PDMS sheet with a thickness of 4 μm. Thus we demonstrated the micromachining of PDMS sheets using laser plasma EUV light.

  14. Laser light scattering as a probe of fractal colloid aggregates

    NASA Technical Reports Server (NTRS)

    Weitz, David A.; Lin, M. Y.

    1989-01-01

    The extensive use of laser light scattering is reviewed, both static and dynamic, in the study of colloid aggregation. Static light scattering enables the study of the fractal structure of the aggregates, while dynamic light scattering enables the study of aggregation kinetics. In addition, both techniques can be combined to demonstrate the universality of the aggregation process. Colloidal aggregates are now well understood and therefore represent an excellent experimental system to use in the study of the physical properties of fractal objects. However, the ultimate size of fractal aggregates is fundamentally limited by gravitational acceleration which will destroy the fractal structure as the size of the aggregates increases. This represents a great opportunity for spaceborne experimentation, where the reduced g will enable the growth of fractal structures of sufficient size for many interesting studies of their physical properties.

  15. Hybrid approach for structural modeling of biological systems from X-ray free electron laser diffraction patterns.

    PubMed

    Tokuhisa, Atsushi; Jonic, Slavica; Tama, Florence; Miyashita, Osamu

    2016-06-01

    We present a new hybrid approach for structural modeling using X-ray free electron laser (XFEL) diffraction patterns from non-crystalline biological samples. Reconstruction of a 3D structure requires a large number of diffraction patterns; however, in the current XFEL experiments with biological systems, the analysis often relies on a small number of 2D diffraction patterns. In this study, we explore the strategies to identify plausible 3D structural models by combining the 2D analysis of such diffraction patterns with computational modeling (normal mode analysis or molecular dynamics simulations). As the first step toward such hybrid modeling, we established a protocol to assess the agreement between the model structure and the target XFEL diffraction pattern and showed that XFEL data can be used to study the conformational transitions of biological molecules. We tested the proposed algorithms using data of three biomolecular complexes of different sizes (elongation factor 2, CCM virus, and ribosome) and examined the experimental conditions that are required to perform such studies, in particular the XFEL beam intensity requirements. The results indicate that the current beam intensity is close to a strength that enables us to study conformational transitions of macromolecules, such as ribosomes. The proposed algorithm can be combined with molecular mechanics approaches, such as molecular dynamics simulations and normal mode analysis, to generate a large number of candidate structures to perform hybrid structural modeling. PMID:26972893

  16. Hybrid approach for structural modeling of biological systems from X-ray free electron laser diffraction patterns.

    PubMed

    Tokuhisa, Atsushi; Jonic, Slavica; Tama, Florence; Miyashita, Osamu

    2016-06-01

    We present a new hybrid approach for structural modeling using X-ray free electron laser (XFEL) diffraction patterns from non-crystalline biological samples. Reconstruction of a 3D structure requires a large number of diffraction patterns; however, in the current XFEL experiments with biological systems, the analysis often relies on a small number of 2D diffraction patterns. In this study, we explore the strategies to identify plausible 3D structural models by combining the 2D analysis of such diffraction patterns with computational modeling (normal mode analysis or molecular dynamics simulations). As the first step toward such hybrid modeling, we established a protocol to assess the agreement between the model structure and the target XFEL diffraction pattern and showed that XFEL data can be used to study the conformational transitions of biological molecules. We tested the proposed algorithms using data of three biomolecular complexes of different sizes (elongation factor 2, CCM virus, and ribosome) and examined the experimental conditions that are required to perform such studies, in particular the XFEL beam intensity requirements. The results indicate that the current beam intensity is close to a strength that enables us to study conformational transitions of macromolecules, such as ribosomes. The proposed algorithm can be combined with molecular mechanics approaches, such as molecular dynamics simulations and normal mode analysis, to generate a large number of candidate structures to perform hybrid structural modeling.

  17. Fast in situ phase and stress analysis during laser surface treatment: a synchrotron x-ray diffraction approach.

    PubMed

    Kostov, V; Gibmeier, J; Wilde, F; Staron, P; Rössler, R; Wanner, A

    2012-11-01

    An in situ stress analysis by means of synchrotron x-ray diffraction was carried out during laser surface hardening of steel. A single exposure set-up that based on a special arrangement of two fast silicon strip line detectors was established, allowing for fast stress analysis according to the sin(2)ψ x-ray analysis method. For the in situ experiments a process chamber was designed and manufactured, which is described in detail. First measurements were carried out at the HZG undulator imaging beamline (IBL, beamline P05) at the synchrotron storage ring PETRA III, DESY, Hamburg (Germany). The laser processing was carried out using a 6 kW high power diode laser system. Two different laser optics were compared, a Gaussian optic with a focus spot of ø 3 mm and a homogenizing optic with a rectangular spot dimension of 8 × 8 mm(2). The laser processing was carried out using spot hardening at a heating-/cooling rate of 1000 K/s and was controlled via pyrometric temperature measurement using a control temperature of 1150 °C. The set-up being established during the measuring campaign allowed for this first realization data collection rates of 10Hz. The data evaluation procedure applied enables the separation of thermal from elastic strains and gains unprecedented insight into the laser hardening process.

  18. 5.5 W near-diffraction-limited power from resonant leaky-wave coupled phase-locked arrays of quantum cascade lasers

    NASA Astrophysics Data System (ADS)

    Kirch, J. D.; Chang, C.-C.; Boyle, C.; Mawst, L. J.; Lindberg, D.; Earles, T.; Botez, D.

    2015-02-01

    Five, 8.36 μm-emitting quantum-cascade lasers (QCLs) have been monolithically phase-locked in the in-phase array mode via resonant leaky-wave coupling. The structure is fabricated by etch and regrowth which provides large index steps (Δn = 0.10) between antiguided-array elements and interelement regions. Such high index contrast photonic-crystal (PC) lasers have more than an order of magnitude higher index contrast than PC-distributed feedback lasers previously used for coherent beam combining in QCLs. Absorption loss to metal layers inserted in the interelement regions provides a wide (˜1.0 μm) range in interelement width over which the resonant in-phase mode is strongly favored to lase. Room-temperature, in-phase-mode operation with ˜2.2 kA/cm2 threshold-current density is obtained from 105 μm-wide aperture devices. The far-field beam pattern has lobewidths 1.65× diffraction limit (D.L.) and 82% of the light in the main lobe, up to 1.8× threshold. Peak pulsed near-D.L. power of 5.5 W is obtained, with 4.5 W emitted in the main lobe. Means of how to increase the device internal efficiency are discussed.

  19. 5.5 W near-diffraction-limited power from resonant leaky-wave coupled phase-locked arrays of quantum cascade lasers

    SciTech Connect

    Kirch, J. D.; Chang, C.-C.; Boyle, C.; Mawst, L. J.; Botez, D.; Lindberg, D.; Earles, T.

    2015-02-09

    Five, 8.36 μm-emitting quantum-cascade lasers (QCLs) have been monolithically phase-locked in the in-phase array mode via resonant leaky-wave coupling. The structure is fabricated by etch and regrowth which provides large index steps (Δn = 0.10) between antiguided-array elements and interelement regions. Such high index contrast photonic-crystal (PC) lasers have more than an order of magnitude higher index contrast than PC-distributed feedback lasers previously used for coherent beam combining in QCLs. Absorption loss to metal layers inserted in the interelement regions provides a wide (∼1.0 μm) range in interelement width over which the resonant in-phase mode is strongly favored to lase. Room-temperature, in-phase-mode operation with ∼2.2 kA/cm{sup 2} threshold-current density is obtained from 105 μm-wide aperture devices. The far-field beam pattern has lobewidths 1.65× diffraction limit (D.L.) and 82% of the light in the main lobe, up to 1.8× threshold. Peak pulsed near-D.L. power of 5.5 W is obtained, with 4.5 W emitted in the main lobe. Means of how to increase the device internal efficiency are discussed.

  20. Laser light triggered-activated carbon nanosystem for cancer therapy.

    PubMed

    Chu, Maoquan; Peng, Jinliang; Zhao, Jiajia; Liang, Shanlu; Shao, Yuxiang; Wu, Qiang

    2013-02-01

    Among carbon-based nanomaterials, activated carbon (AC) may be an ideal candidate as a carrier for tumor therapeutic agents. Here we found a new property of nanoscale activated carbon (NAC) with narrow size distribution, namely the rapid conversion of light to thermal energy both in vitro and in vivo. An aqueous suspension of 200 μL of NAC (1 mg/mL) exhibited a rapid temperature increase of more than 35 °C after irradiation for 20 min with a 655-nm laser; this was within the temperature range for effective tumor treatment. We demonstrated that lung cancer cells (H-1299) incubated with bamboo nano-AC (BNAC) were killed with high efficiency after laser irradiation. In addition, mouse tumors with sizes smaller than the laser spot that had been injected with BNAC disappeared after irradiation. For tumors larger than the laser spot area, the incorporation of the photosensitizer ZnPc obviously increased the tumor growth inhibition efficiency of BNAC. BNAC-ZnPc was found to exhibit a synergistic effect when photothermal and photodynamic therapies were administered in combination. These results indicated that NAC can be used for high efficiency cancer phototherapy.

  1. UV-laser-based longitudinal illuminated diffuser (LID) incorporating diffractive and Lambertian reflectance for the disinfection of beverages

    NASA Astrophysics Data System (ADS)

    Lizotte, Todd

    2010-08-01

    A novel laser beam shaping system was designed to demonstrate the potential of using high power UV laser sources for large scale disinfection of liquids used in the production of food products, such as juices, beer, milk and other beverage types. The design incorporates a patented assembly of optical components including a diffractive beam splitting/shaping element and a faceted pyramidal or conically shaped Lambertian diffuser made from a compression molded PTFE compounds. When properly sintered to an appropriate density, as an example between 1.10 and 1.40 grams per cubic centimeter, the compressed PTFE compounds show a ~99% reflectance at wavelengths ranging from 300 nm to 1500 nm, and a ~98.5% refection of wavelengths from 250 nm to 2000 nm [1]. The unique diffuser configuration also benefits from the fact that the PTFE compounds do not degrade when exposed to ultraviolet radiation as do barium sulfate materials and silver or aluminized mirror coatings [2]. These components are contained within a hermetically sealed quartz tube. Once assembled a laser beam is directed through one end of the tube. This window takes the form of a computer generated diffractive splitter or other diffractive shaper element to split the laser beam into a series of spot beamlets, circular rings or other geometric shapes. As each of the split beamlets or rings cascade downward, they illuminate various points along the tapered PTFE cone or faceted pyramidal form. As they strike the surface they each diffuse in a Lambertian reflectance pattern creating a pseudo-uniform circumferential illuminator along the length of the quartz tube enclosing the assembly. The compact tubular structure termed Longitudinal Illuminated Diffuser (LID) provides a unique UV disinfection source that can be placed within a centrifugal reactor or a pipe based reactor chamber. This paper will review the overall design principle, key component design parameters, preliminary analytic and bench operational testing

  2. Light-curing polymers for laser plasma generation

    NASA Astrophysics Data System (ADS)

    Loktionov, E. Y.; Protasov, Y. S.; Protasov, Y. Y.; Telekh, V. D.

    2015-07-01

    Solid rather than liquid media are used in pulsed laser plasma generators despite sophisticated transportation and dosing system need for a long-term operation. Liquid media could be more preferable due to transfer and dosing (down to 10-14 L) being well developed, but plasma generation of those results in intense droplet formation and kinetic energy losses. Combination of liquids transportation advantages and solids plasma generation efficiency might resolve this trade-off. Liquid-to-solid transition can be induced by cooling down to sublimation temperature, thermo-, photo- or electron induced polymerization (curing). Light cured polymers seem to be very useful as active media for plasma generators, since they can be solidified very fast (ca. 30 ms) just before impact. We considered experimentally several UV- curing polymer and mixtures ablation regimes and supply schemes for laser plasma generation. The best results were obtained for liquid polymer at high-power pulsed irradiation matching curing optimum wavelength.

  3. Overcoming the diffraction limit using multiple light scattering in a highly disordered medium.

    PubMed

    Choi, Youngwoon; Yang, Taeseok Daniel; Fang-Yen, Christopher; Kang, Pilsung; Lee, Kyoung Jin; Dasari, Ramachandra R; Feld, Michael S; Choi, Wonshik

    2011-07-01

    We report that disordered media made of randomly distributed nanoparticles can be used to overcome the diffraction limit of a conventional imaging system. By developing a method to extract the original image information from the multiple scattering induced by the turbid media, we dramatically increase a numerical aperture of the imaging system. As a result, the resolution is enhanced by more than 5 times over the diffraction limit, and the field of view is extended over the physical area of the camera. Our technique lays the foundation to use a turbid medium as a far-field superlens.

  4. Spectrum of reflected light by self-focusing of light in a laser plasma

    SciTech Connect

    Gorbunov, L.M.

    1983-05-01

    The spectrum of the radiation reflected by a laser-produced plasma is considered. In this situation, self-focusing occurs and a region of low density (caviton) is formed. It is shown that the process leads to a considerable broadening of the spectrum on the ''red'' side, and to the appearance of a line structure in the spectrum. The results can explain data for the reflected light spectrum (L. M. Gorbunov et al., FIAN Preprint No. 126 (1979)) as being due to the nonstationary self-focusing of light in a laser-produced plasma that has recently been observed (V. L. Artsimovich et al., FIAN Preprint No. 252 (1981); Sov. Phys. Doklady 27, 618 (1982)).

  5. Laser biostimulation of patients suffering from multiple sclerosis in respect to the biological influence of laser light

    NASA Astrophysics Data System (ADS)

    Peszynski-Drews, Cezary; Klimek, Andrzej; Sopinski, Marek; Obrzejta, Dominik

    2003-10-01

    The authors discuss the results, obtained so far during three years' clinical examination, of laser therapy in the treatment of patients suffering from multiple sclerosis. They regard both the results of former laboratory experiments and so far discovered mechanisms of biological influence of laser light as an objective explanation of high effectiveness of laser therapy in the csae of this so far incurable disease. They discuss wide range of biological mechanisms of laser therapy, examined so far on different levels (cell, tissue, organ), allowing the explanation of beneficial influence of laser light in pathogenetically different morbidities.

  6. Ultrabright Laser-based MeV-class Light Source

    SciTech Connect

    Albert, F; Anderson, G; Anderson, S; Bayramian, A; Berry, B; Betts, S; Dawson, J; Ebbers, C; Gibson, D; Hagmann, C; Hall, J; Hartemann, F; Hartouni, E; Heebner, J; Hernandez, J; Johnson, M; Messerly, M; McNabb, D; Phan, H; Pruet, J; Semenov, V; Shverdin, M; Sridharan, A; Tremaine, A; Siders, C W; Barty, C J

    2008-04-02

    We report first light from a novel, new source of 10-ps 0.776-MeV gamma-ray pulses known as T-REX (Thomson-Radiated Extreme X-rays). The MeV-class radiation produced by TREX is unique in the world with respect to its brightness, spectral purity, tunability, pulse duration and laser-like beam character. With T-REX, one can use photons to efficiently probe and excite the isotope-dependent resonant structure of atomic nucleus. This ability will be enabling to an entirely new class of isotope-specific, high resolution imaging and detection capabilities.

  7. Laser light-scattering diagnostic of blood protein solutions

    NASA Astrophysics Data System (ADS)

    Petrova, Galina P.; Petrusevich, Yurii M.; Ten, Dmitrii I.; Boiko, A. V.; Fadyukova, Olga E.

    2003-11-01

    Molecular methods of diagnostics of widespread diseases including vascular pathology on the base static and dynamic laser light scattering in serum blood solution are testified. The alterations of molecular parameters of blood serum of animal species (rats) after experimentally induced cerebral ischemia (hypoxia) and haemorrhagic stroke relative to controls were studied. It was obtained that effective mass of scattering particles in blood serum solutions is diminished for haemorrhagic and ischemic rats in comparison to control. The relative protein concentrations in blood serum also change both after false operation and in case of induced ischemia.

  8. Reflectives: Phosphors and lasers - shedding light on rare earths

    SciTech Connect

    Tonneson, L.C.; Fox, G.J.

    1996-04-01

    The first powder electroluminescent phosphor was introduced in 1936. Today, phosphors, particularly those made of high-purity rare earths, have found their way into a variety of products: industrial, commercial, and consumer, alike. The fluorescent lamp industry which remains the leading market for the use of high-purity rare earths, lit the way for the future of rare earths in the optical, x-ray, and display screen applications. Light combined with rare earth materials is also a successful recipe for reflectivity needed in filtering applications such as optics, lasers, and conductors. This article discusses the applications and markets for phosphors and rare earths.

  9. Laser diode end-pumped continuous-wave laser operation at 1339 nm in Nd : GGG with nearly diffraction-limited beam quality

    NASA Astrophysics Data System (ADS)

    Lin, Zhi; Wang, Yi; Xu, Bin; Cheng, Yongjie; Chen, Nan; Xu, Huiying; Cai, Zhiping

    2015-08-01

    We report on the laser diode end-pumped continuous-wave laser operation of a Nd : GGG single crystal at 1339 nm in a plane parallel laser cavity configuration, for the first time to our knowledge. A simultaneous tri-wavelength laser at 1324, 1331 and 1337 nm is obtained at first with a maximum output power up to 1.66 W in a free-running laser operation with a slope efficiency of about 27.6% with respect to the absorbed pump power. By inserting a 0.1 mm glass etalon into the laser cavity and finely tilting it to a suitable angle, a single wavelength lasing at 1339 nm can be realized with a maximum output power of 0.58 W and slope efficiency of about 12.9%. The output power stability is simply estimated to be about 4.1% and the output beam quality is measured to be as near the diffraction limit as 1.33 and 1.16 in x and y directions, respectively.

  10. Microstructured Air Cavities as High-Index Contrast Substrates with Strong Diffraction for Light-Emitting Diodes.

    PubMed

    Moon, Yoon-Jong; Moon, Daeyoung; Jang, Jeonghwan; Na, Jin-Young; Song, Jung-Hwan; Seo, Min-Kyo; Kim, Sunghee; Bae, Dukkyu; Park, Eun Hyun; Park, Yongjo; Kim, Sun-Kyung; Yoon, Euijoon

    2016-05-11

    Two-dimensional high-index-contrast dielectric gratings exhibit unconventional transmission and reflection due to their morphologies. For light-emitting devices, these characteristics help guided modes defeat total internal reflections, thereby enhancing the outcoupling efficiency into an ambient medium. However, the outcoupling ability is typically impeded by the limited index contrast given by pattern media. Here, we report strong-diffraction, high-index-contrast cavity engineered substrates (CESs) in which hexagonally arranged hemispherical air cavities are covered with a 80 nm thick crystallized alumina shell. Wavelength-resolved diffraction measurements and Fourier analysis on GaN-grown CESs reveal that the high-index-contrast air/alumina core/shell patterns lead to dramatic excitation of the low-order diffraction modes. Large-area (1075 × 750 μm(2)) blue-emitting InGaN/GaN light-emitting diodes (LEDs) fabricated on a 3 μm pitch CES exhibit ∼39% enhancement in the optical power compared to state-of-the-art, patterned-sapphire-substrate LEDs, while preserving all of the electrical metrics that are relevant to LED devices. Full-vectorial simulations quantitatively demonstrate the enhanced optical power of CES LEDs and show a progressive increase in the extraction efficiency as the air cavity volume is expanded. This trend in light extraction is observed for both lateral- and flip-chip-geometry LEDs. Measurements of far-field profiles indicate a substantial beaming effect for CES LEDs, despite their few-micron-pitch pattern. Near-to-far-field transformation simulations and polarization analysis demonstrate that the improved extraction efficiency of CES LEDs is ascribed to the increase in emissions via the top escape route and to the extraction of transverse-magnetic polarized light.

  11. Optical-diffraction method for determining crystal orientation

    DOEpatents

    Sopori, B.L.

    1982-05-07

    Disclosed is an optical diffraction technique for characterizing the three-dimensional orientation of a crystal sample. An arbitrary surface of the crystal sample is texture etched so as to generate a pseudo-periodic diffraction grating on the surface. A laser light beam is then directed onto the etched surface, and the reflected light forms a farfield diffraction pattern in reflection. Parameters of the diffraction pattern, such as the geometry and angular dispersion of the diffracted beam are then related to grating shape of the etched surface which is in turn related to crystal orientation. This technique may be used for examining polycrystalline silicon for use in solar cells.

  12. Reverse color sequence in the diffraction of white light by the wing of the male butterfly Pierella luna (Nymphalidae: Satyrinae).

    PubMed

    Vigneron, Jean Pol; Simonis, Priscilla; Aiello, Annette; Bay, Annick; Windsor, Donald M; Colomer, Jean-François; Rassart, Marie

    2010-08-01

    The butterfly Pierella luna (Nymphalidae) shows an intriguing rainbow iridescence effect: the forewings of the male, when illuminated along the axis from the body to the wing tip, decompose a white light beam as a diffraction grating would do. Violet light, however, emerges along a grazing angle, near the wing surface, while the other colors, from blue to red, exit respectively at angles progressively closer to the direction perpendicular to the wing plane. This sequence is the reverse of the usual decomposition of light by a grating with a periodicity parallel to the wing surface. It is shown that this effect is produced by a macroscopic deformation of the entire scale, which curls in such a way that it forms a "vertical" grating, perpendicular to the wing surface, and functions in transmission instead of reflection.

  13. Synchronization of video recording and laser pulses including background light suppression

    NASA Technical Reports Server (NTRS)

    Kalshoven, Jr., James E. (Inventor); Tierney, Jr., Michael (Inventor); Dabney, Philip W. (Inventor)

    2004-01-01

    An apparatus for and a method of triggering a pulsed light source, in particular a laser light source, for predictable capture of the source by video equipment. A frame synchronization signal is derived from the video signal of a camera to trigger the laser and position the resulting laser light pulse in the appropriate field of the video frame and during the opening of the electronic shutter, if such shutter is included in the camera. Positioning of the laser pulse in the proper video field allows, after recording, for the viewing of the laser light image with a video monitor using the pause mode on a standard cassette-type VCR. This invention also allows for fine positioning of the laser pulse to fall within the electronic shutter opening. For cameras with externally controllable electronic shutters, the invention provides for background light suppression by increasing shutter speed during the frame in which the laser light image is captured. This results in the laser light appearing in one frame in which the background scene is suppressed with the laser light being uneffected, while in all other frames, the shutter speed is slower, allowing for the normal recording of the background scene. This invention also allows for arbitrary (manual or external) triggering of the laser with full video synchronization and background light suppression.

  14. Deep ultraviolet light-emitting and laser diodes

    NASA Astrophysics Data System (ADS)

    Khan, Asif; Asif, Fatima; Muhtadi, Sakib

    2016-02-01

    Nearly all the air-water purification/polymer curing systems and bio-medical instruments require 250-300 nm wavelength ultraviolet light for which mercury lamps are primarily used. As a potential replacement for these hazardous mercury lamps, several global research teams are developing AlGaN based Deep Ultraviolet (DUV) light emitting diodes (LEDs) and DUV LED Lamps and Laser Diodes over Sapphire and AlN substrates. In this paper, we review the current research focus and the latest device results. In addition to the current results we also discuss a new quasipseudomorphic device design approach. This approach which is much easier to integrate in a commercial production setting was successfully used to demonstrate UVC devices on Sapphire substrates with performance levels equal to or better than the conventional relaxed device designs.

  15. Laser and light-based treatment options for hidradenitis suppurativa.

    PubMed

    Hamzavi, Iltefat H; Griffith, James L; Riyaz, Farhaad; Hessam, Schapoor; Bechara, Falk G

    2015-11-01

    Hidradenitis suppurativa (HS) is a chronic inflammatory disease that commonly develops painful, deep dermal abscesses and chronic, draining sinus tracts. Classically, pharmacologic and surgical therapies have been effective for reducing lesion activity and inflammation, but provide only modest success in the prevention of future recurrences and disease progression. Adjunctive therapies, such as laser and light-based therapies, have become more commonly used in the management of HS. These therapies work to reduce the occurrence of painful HS flare-ups by decreasing the number of hair follicles, sebaceous glands, and bacteria in affected areas, and by ablatively debulking chronic lesions. The best results are seen when treatment is individualized, taking disease severity into consideration when selecting specific energy-based approaches. This article will discuss various light-based therapies and the evidence supporting their use in the management of HS.

  16. 7 Å Resolution in Protein 2-Dimentional-Crystal X-Ray Diffraction at Linac Coherent Light Source

    SciTech Connect

    Pedrini, Bill; Tsai, Ching-Ju; Capitani, Guido; Padeste, Celestino; Hunter, Mark; Zatsepin, Nadia A.; Barty, Anton; Benner, Henry; Boutet, Sebastien; Feld, Geoffrey K.; Hau-Riege, Stefan; Kirian, Rick; Kupitz, Christopher; Messerschmidt, Marc; Ogren, John I.; Pardini, Tommaso; Segelke, Brent; Williams, Garth J.; Spence , John C.; Abela, Rafael; Coleman, Matthew A.; Evans, James E.; Schertler, Gebhard; Frank, Matthias; Li, Xiao-Dan

    2014-06-09

    Membrane proteins arranged as two-dimensional (2D) crystals in the lipid en- vironment provide close-to-physiological structural information, which is essential for understanding the molecular mechanisms of protein function. X-ray diffraction from individual 2D crystals did not represent a suitable investigation tool because of radiation damage. The recent availability of ultrashort pulses from X-ray Free Electron Lasers (X-FELs) has now provided a mean to outrun the damage. Here we report on measurements performed at the LCLS X-FEL on bacteriorhodopsin 2D crystals mounted on a solid support and kept at room temperature. By merg- ing data from about a dozen of single crystal diffraction images, we unambiguously identified the diffraction peaks to a resolution of 7 °A, thus improving the observable resolution with respect to that achievable from a single pattern alone. This indicates that a larger dataset will allow for reliable quantification of peak intensities, and in turn a corresponding increase of resolution. The presented results pave the way to further X-FEL studies on 2D crystals, which may include pump-probe experiments at subpicosecond time resolution.

  17. Single-pulse enhanced coherent diffraction imaging of bacteria with an X-ray free-electron laser

    PubMed Central

    Fan, Jiadong; Sun, Zhibin; Wang, Yaling; Park, Jaehyun; Kim, Sunam; Gallagher-Jones, Marcus; Kim, Yoonhee; Song, Changyong; Yao, Shengkun; Zhang, Jian; Zhang, Jianhua; Duan, Xiulan; Tono, Kensuke; Yabashi, Makina; Ishikawa, Tetsuya; Fan, Chunhai; Zhao, Yuliang; Chai, Zhifang; Gao, Xueyun; Earnest, Thomas; Jiang, Huaidong

    2016-01-01

    High-resolution imaging offers one of the most promising approaches for exploring and understanding the structure and function of biomaterials and biological systems. X-ray free-electron lasers (XFELs) combined with coherent diffraction imaging can theoretically provide high-resolution spatial information regarding biological materials using a single XFEL pulse. Currently, the application of this method suffers from the low scattering cross-section of biomaterials and X-ray damage to the sample. However, XFELs can provide pulses of such short duration that the data can be collected using the “diffract and destroy” approach before the effects of radiation damage on the data become significant. These experiments combine the use of enhanced coherent diffraction imaging with single-shot XFEL radiation to investigate the cellular architecture of Staphylococcus aureus with and without labeling by gold (Au) nanoclusters. The resolution of the images reconstructed from these diffraction patterns were twice as high or more for gold-labeled samples, demonstrating that this enhancement method provides a promising approach for the high-resolution imaging of biomaterials and biological systems. PMID:27659203

  18. Single-pulse enhanced coherent diffraction imaging of bacteria with an X-ray free-electron laser

    NASA Astrophysics Data System (ADS)

    Fan, Jiadong; Sun, Zhibin; Wang, Yaling; Park, Jaehyun; Kim, Sunam; Gallagher-Jones, Marcus; Kim, Yoonhee; Song, Changyong; Yao, Shengkun; Zhang, Jian; Zhang, Jianhua; Duan, Xiulan; Tono, Kensuke; Yabashi, Makina; Ishikawa, Tetsuya; Fan, Chunhai; Zhao, Yuliang; Chai, Zhifang; Gao, Xueyun; Earnest, Thomas; Jiang, Huaidong

    2016-09-01

    High-resolution imaging offers one of the most promising approaches for exploring and understanding the structure and function of biomaterials and biological systems. X-ray free-electron lasers (XFELs) combined with coherent diffraction imaging can theoretically provide high-resolution spatial information regarding biological materials using a single XFEL pulse. Currently, the application of this method suffers from the low scattering cross-section of biomaterials and X-ray damage to the sample. However, XFELs can provide pulses of such short duration that the data can be collected using the “diffract and destroy” approach before the effects of radiation damage on the data become significant. These experiments combine the use of enhanced coherent diffraction imaging with single-shot XFEL radiation to investigate the cellular architecture of Staphylococcus aureus with and without labeling by gold (Au) nanoclusters. The resolution of the images reconstructed from these diffraction patterns were twice as high or more for gold-labeled samples, demonstrating that this enhancement method provides a promising approach for the high-resolution imaging of biomaterials and biological systems.

  19. Tunable diffraction grating using ultraviolet-light-induced spatial phase modulation in dual-frequency liquid crystal

    SciTech Connect

    Lin, P.-T.; Liang Xiao; Ren Hongwen; Wu, S.-T.

    2004-08-16

    An electrically tunable diffraction phase grating using ultraviolet (UV)-light-induced spatial dielectric modulation of a dual-frequency liquid crystal (DFLC) cell is demonstrated. A photomask with transparent and opaque stripes was used for fabricating the grating. In the UV-exposed stripes, the negative dielectric anisotropy ({delta}{epsilon}) tolane compound of the DFLC mixture is partially polymerized resulting in a decreased threshold voltage as compared to that of the unexposed region. Upon applying a constant voltage, the phase difference between the adjacent pixels is produced. The first-order diffraction efficiency reaches {approx}60% which agrees well with the simulation results. Due to the dual-frequency addressing at 30 V{sub rms}, the response time of the DFLC phase grating was measured to be {approx}1 ms at room temperature.

  20. Tunable diffraction grating using ultraviolet-light-induced spatial phase modulation in dual-frequency liquid crystal

    NASA Astrophysics Data System (ADS)

    Lin, Pao-Tai; Liang, Xiao; Ren, Hongwen; Wu, Shin-Tson

    2004-08-01

    An electrically tunable diffraction phase grating using ultraviolet (UV)-light-induced spatial dielectric modulation of a dual-frequency liquid crystal (DFLC) cell is demonstrated. A photomask with transparent and opaque stripes was used for fabricating the grating. In the UV-exposed stripes, the negative dielectric anisotropy (Δɛ) tolane compound of the DFLC mixture is partially polymerized resulting in a decreased threshold voltage as compared to that of the unexposed region. Upon applying a constant voltage, the phase difference between the adjacent pixels is produced. The first-order diffraction efficiency reaches ˜60% which agrees well with the simulation results. Due to the dual-frequency addressing at 30Vrms, the response time of the DFLC phase grating was measured to be ˜1ms at room temperature.

  1. Nanosecond x-Ray diffraction from polycrystalline and amorphous materials in a pinhole camera geometry suitable for laser shock compression experiments

    SciTech Connect

    Hawreliak, J.; Lorenzana, H. E.; Remington, B. A.; Lukezic, S.; Wark, J. S.

    2007-08-15

    Nanosecond pulses of quasimonochromatic x-rays emitted from the K shell of ions within a laser-produced plasma are of sufficient spectral brightness to allow single-shot recording of powder diffraction patterns from thin foils of order millimeter diameter. Strong diffraction signals have been observed in a cylindrical pinhole camera arrangement from both polycrystalline and amorphous foils, and the experimental arrangement and foil dimensions are such that they allow for laser shocking or quasi-isentropic loading of the foil during the diffraction process.

  2. Nanosecond x-ray diffraction from polycrystalline and amorphous materials in a pinhole camera geometry suitable for laser shock compression experiments.

    PubMed

    Hawreliak, J; Lorenzana, H E; Remington, B A; Lukezic, S; Wark, J S

    2007-08-01

    Nanosecond pulses of quasimonochromatic x-rays emitted from the K shell of ions within a laser-produced plasma are of sufficient spectral brightness to allow single-shot recording of powder diffraction patterns from thin foils of order millimeter diameter. Strong diffraction signals have been observed in a cylindrical pinhole camera arrangement from both polycrystalline and amorphous foils, and the experimental arrangement and foil dimensions are such that they allow for laser shocking or quasi-isentropic loading of the foil during the diffraction process.

  3. Diffractive Combiner of Single-Mode Pump Laser-Diode Beams

    NASA Technical Reports Server (NTRS)

    Liu, Duncan; Wilson, Daniel; Qiu, Yueming; Forouhar, Siamak

    2007-01-01

    An optical beam combiner now under development would make it possible to use the outputs of multiple single-mode laser diodes to pump a neodymium: yttrium aluminum garnet (Nd:YAG) nonplanar ring oscillator (NPRO) laser while ensuring that the laser operates at only a single desired frequency. Heretofore, an Nd:YAG NPRO like the present one has been pumped by a single multimode laser-diode beam delivered via an optical fiber. It would be desirable to use multiple pump laser diodes to increase reliability beyond that obtainable from a single pump laser diode. However, as explained below, simplistically coupling multiple multimode laser-diode beams through a fiber-optic combiner would entail a significant reduction in coupling efficiency, and lasing would occur at one or more other frequencies in addition to the single desired frequency. Figure 1 schematically illustrates the principle of operation of a laser-diode-pumped Nd:YAG NPRO. The laser beam path is confined in a Nd:YAG crystal by means of total internal reflections on the three back facets and a partial-reflection coating on the front facet. The wavelength of the pump beam - 808 nm - is the wavelength most strongly absorbed by the Nd:YAG crystal. The crystal can lase at a wavelength of either 1,064 nm or 1,319 nm - which one depending on the optical coating on the front facet. A thermal lens effect induced by the pump beam enables stable lasing in the lowest-order transverse electromagnetic mode (the TEM00 mode). The frequency of this laser is very stable because of the mechanical stability of the laser crystal and the unidirectional nature of the lasing. The unidirectionality is a result of the combined effects of (1) a Faraday rotation induced by an externally applied magnetic field and (2) polarization associated with non-normal incidence and reflection on the front facet.

  4. Application of diffraction tomography theory to determine size and shape of spheroidal particles from light scattering

    NASA Astrophysics Data System (ADS)

    Ding, Chizhu; Yang, Kecheng; Li, Wei; Guo, Wenping; Zhang, Xiaohui; Xia, Min

    2014-10-01

    Discerning the geometry of spheroidal scatterers of micron order is an important topic in identifying marine microbes. Optical diffraction tomography theory indicates that under the first-order Born approximation for weak scattering, scattering amplitude in the far zone and scattering potential of the scatterer have a Fourier relationship. In this paper, we describe a method based on diffraction tomography theory and determine the size and the shape of spheroidal scatterers by reconstructing the distribution of scattering potential from angular resolved scattered field. As a demonstration of this method, the scattering from spheroidal particles with equal-volume-sphere radii of 0.5429, 1.00, and 2.00 μm and an aspect ratio that varies from 0.4 to 1.5 was modeled by using T-matrix theory and used as test data. Simulation results show that in the case of low contrast, size and shape determination can be achieved with sub-wavelength precision.

  5. Performance of ferroelectric liquid crystal spatial light modulators for polarization and color diffractive elements

    NASA Astrophysics Data System (ADS)

    Moreno, Ignacio; García-Martínez, P.; Sánchez-López, M. M.; Martínez-García, A.; Martínez, J. L.

    2009-08-01

    In this work we applied a ferroelectric liquid crystal on silicon (FLCoS) display for implementing monochrome and color diffractive optical elements (DOE). We first apply a reverse engineering process specifically adapted to characterize the optical parameters of a commercial FLCoS display, specifically the phase shift and the tilt angle. We then analyze the performance of the device for implementing a binary polarization diffraction grating (PDG), and how it adopts the form of either a binary amplitude grating or a binary phase grating as particular cases when the polarization states emerging from the display are projected to an analyzer. As a final experiment, we have applied the FLCoS display to generate RGB improved dynamic color binary-phase Fourier computer-generated holograms (CGHs). We have electronically synchronized the properly scaled image addressed to the display with a color filter wheel with RGB filters. Experimental results show an excellent chromatic compensation of the color image reconstruction.

  6. Orbital motion of spherical microparticles trapped in diffraction patterns of circularly polarized light

    SciTech Connect

    Adachi, Hiroto; Akahoshi, Shin; Miyakawa, Kenji

    2007-06-15

    We investigate arrays and rotation of spherical microparticles trapped by focusing a circularly polarized Gaussian beam just above the top coverslip-water interface. Particles are trapped in various patterns due to a Fresnel diffraction, such as rings and close-packed structures. We find that rings of particles orbit around the beam axis, whereas close-packed arrays spin in the opposite sense on the beam axis. The sense of the orbiting, as well as that of the spinning, is determined by the input circular polarization handedness. The results are interpreted on the assumption that the spin angular momentum carried by a circularly polarized beam is converted into the orbital angular momentum in the optical process by which the focused Gaussian beam's shape is transformed due to diffraction.

  7. Super-luminescent jet light generated by femtosecond laser pulses

    PubMed Central

    Xu, Zhijun; Zhu, Xiaonong; Yu, Yang; Zhang, Nan; Zhao, Jiefeng

    2014-01-01

    Phenomena of nonlinear light-matter interaction that occur during the propagation of intense ultrashort laser pulses in continuous media have been extensively studied in ultrafast optical science. In this vibrant research field, conversion of the input laser beam into optical filament(s) is commonly encountered. Here, we demonstrate generation of distinctive single or double super-luminescent optical jet beams as a result of strong spatial-temporal nonlinear interaction between focused 50 fs millijoule laser pulses and their induced micro air plasma. Such jet-like optical beams, being slightly divergent and coexisting with severely distorted conical emission of colored speckles, are largely different from optical filaments, and obtainable when the focal lens of proper f-number is slightly tilted or shifted. Once being collimated, the jet beams can propagate over a long distance in air. These beams not only reveal a potentially useful approach to coherent optical wave generation, but also may find applications in remote sensing. PMID:24463611

  8. Fluvial suspended sediment characteristics by high-resolution, surrogate metrics of turbidity, laser-diffraction, acoustic backscatter, and acoustic attenuation

    NASA Astrophysics Data System (ADS)

    Landers, Mark Newton

    Sedimentation is a primary and growing environmental, engineering, and agricultural issue around the world. However, collection of the data needed to develop solutions to sedimentation issues has declined by about three-fourths since 1983. Suspended-sediment surrogates have the potential to obtain sediment data using methods that are more accurate, of higher spatial and temporal resolution, and with less manually intensive, costly, and hazardous methods. The improved quality of sediment data from high-resolution surrogates may inform improved understanding and solutions to sedimentation problems. The field experiments for this research include physical samples of suspended sediment collected concurrently with surrogate metrics from instruments including 1.2, 1.5, and 3.0 megahertz frequency acoustic doppler current profilers, a nephelometric turbidity sensor, and a laser-diffraction particle size analyzer. This comprehensive data set was collected over five storms in 2009 and 2010 at Yellow River near Atlanta, Georgia. Fluvial suspended sediment characteristics in this study can be determined by high-resolution surrogate parameters of turbidity, laser-diffraction and acoustics with model errors 33% to 49% lower than traditional methods using streamflow alone. Hysteresis in sediment-turbidity relations for single storm events was observed and quantitatively related to PSD changes of less than 10 microns in the fine silt to clay size range. Suspended sediment particle size detection (PSD) is significantly correlated with ratios of measured acoustic attenuation at different frequencies; however the data do not fit the theoretical relations. Using both relative acoustic backscatter (RB) and acoustic attenuation as explanatory variables results in a significantly improved model of suspended sediment compared with traditional sonar equations using only RB. High resolution PSD data from laser diffraction provide uniquely valuable information; however the size detection

  9. a Light-Weight Laser Scanner for Uav Applications

    NASA Astrophysics Data System (ADS)

    Tommaselli, A. M. G.; Torres, F. M.

    2016-06-01

    Unmanned Aerial Vehicles (UAV) have been recognized as a tool for geospatial data acquisition due to their flexibility and favourable cost benefit ratio. The practical use of laser scanning devices on-board UAVs is also developing with new experimental and commercial systems. This paper describes a light-weight laser scanning system composed of an IbeoLux scanner, an Inertial Navigation System Span-IGM-S1, from Novatel, a Raspberry PI portable computer, which records data from both systems and an octopter UAV. The performance of this light-weight system was assessed both for accuracy and with respect to point density, using Ground Control Points (GCP) as reference. Two flights were performed with the UAV octopter carrying the equipment. In the first trial, the flight height was 100 m with six strips over a parking area. The second trial was carried out over an urban park with some buildings and artificial targets serving as reference Ground Control Points. In this experiment a flight height of 70 m was chosen to improve target response. Accuracy was assessed based on control points the coordinates of which were measured in the field. Results showed that vertical accuracy with this prototype is around 30 cm, which is acceptable for forest applications but this accuracy can be improved using further refinements in direct georeferencing and in the system calibration.

  10. A Theoretical Light Scattering Model of Nanoparticle Laser Tweezers

    NASA Technical Reports Server (NTRS)

    Lock, James A.

    2003-01-01

    Accomplishments this reporting period include: 1. derived, programmed, checked, and tested the Mie light scattering theory formulas for the radiation trapping force for both the on-axis and off-axis geometry of the trapping beam plus trapped spherical particle; 2. verified that the computed radiation trapping force for a freely propagating focused Gaussian laser beam incident on a spherical particle agrees with previous published calculations; 3. compared the small particle size and large particle size limits of the Mie calculation with the results of Rayleigh scattering theory and ray scattering theory, respectively and verified that the comparison is correct for Rayleigh scattering theory but found that ray theory omits an important light scattering effect included in the Mie theory treatment; 4. generalized the calculation of the radiation trapping force on a spherical particle in the on-axis geometry from a freely propagating focused Gaussian laser beam to the realistic situation of a Gaussian beam truncated and focused by a high numerical aperture oil-immersion microscope objective lens and aberrated by the interface between the microscope cover slip and the liquid-filled sample volume; and 5. compared the calculated radiation trapping force for this geometry with the results of previously published experiments and found that the agreement is better than when using previously developed theories.

  11. Thermal mechanisms of laser marking in transparent polymers with light-absorbing microparticles

    NASA Astrophysics Data System (ADS)

    Zelenska, K. S.; Zelensky, S. E.; Poperenko, L. V.; Kanev, K.; Mizeikis, V.; Gnatyuk, V. A.

    2016-01-01

    Interaction of highly viscous polystyrene suspensions of light-absorbing microparticles with pulsed radiation of a Q-switched YAG:Nd3+ laser is investigated. Absorption of laser radiation by the suspended microparticles causes thermal decomposition (pyrolysis) of the polymer in the vicinity of the overheated particles. Laser-induced incandescence (LII) of light-absorbing microparticles under irradiation by a sequence of laser pulses is observed. The mechanism of laser marking includes formation of light-absorbing and scattering centers by accumulation of carbonaceous and gaseous products of pyrolysis.

  12. The dynamics of soil aggregate breakdown in water in response to landuse as measured with laser diffraction technique

    NASA Astrophysics Data System (ADS)

    Oyedele, D. J.; Pini, R.; Sparvoli, E.; Scatena, M.

    2012-04-01

    The Mastersizer 2000G (Malvern Instruments) Diffraction Instrument was used to assess and quantify the breakdown of soil aggregates and compute wet aggregate stability indices. The study was aimed at evolving a novel rapid method of determining soil aggregate stability. Bulk surface (0-15 cm) soil samples were collected under 5 different land uses in the Teaching and Resrach Farm of Obafemi Awolowo University, Ile-Ife, Nigeria. About 0.5g of the soils aggregates (0.5 -1 mm diameter) were evaluated in the laser diffractometer with the stirrer operated at 500 rpm and the pump at 1800 rpm. The different size aggregates and particles of sand silt and clay were quantified periodically. Water stable aggregates greater than 250 µm (WSA>250), water stable aggregates less than 250 µm (WSA<250), water dispersible clay index (WDI), and mean volume diameter (MVD) among others were computed from the laser diffraction data. The values were compared with the classical Yoder wet sieving technique. The WSA>250 was significantly higher on the soils under Forest (FR), Cacao (CC), Teak (TK) and Oil Palm (OP) plantations, while it was significantly lowest under no-tillage (NT) and continuous cultivation (CT). The pasture (PD) was not significantly different from either the cultivated and the non-cultivated soils. Conversely, the WSA<250 and water dispersible clay index was highest in the cultivated soils (CT and NT) and lowest in the non-cultivated soils (FR, TK, CC and OP) while the PD was in-between. The MVD also followed a similar trend as the WSA>250. The wet sieving water stable aggregates index (WSI>250) was significantly correlated with WSA>250 (r = 0.75), MVD (r = 0.75), WDI (r = -0.68) and WSA<250 (r = - 0.73). All the laser diffraction measured aggregation indices were significantly correlated with the organic matter contents of the soils. Thus the laser diffraction promises a rapid and comprehensive method of evaluation of soil aggregate stability.

  13. Self-diffraction of ultrashort laser pulses under resonant excitation of excitons in a colloidal solution of CdSe/ZnS quantum dots

    NASA Astrophysics Data System (ADS)

    Dneprovskii, V. S.; Kozlova, M. V.; Smirnov, A. M.

    2013-10-01

    We report self-diffraction processes of two types under resonant excitation of the fundamental electron - hole (exciton) transition in a strongly absorbing colloidal solution of CdSe/ZnS quantum dots (QDs) by high-power picosecond laser pulses. In the first case the absorption saturation (bleaching) at the exciton transition frequency and the Stark shift of exciton absorption line lead to the formation of a transparency channel and self-diffraction of the laser beam from the thus induced round diaphragm. In the second case, self-diffraction of two laser beams, intersecting in a cell with a colloidal QD solution, occurs on the diffraction grating induced by these beams. The physical processes responsible for the nonlinear optical properties of CdSe/ZnS QDs and the found selfaction effects are analysed.

  14. Self-diffraction of ultrashort laser pulses under resonant excitation of excitons in a colloidal solution of CdSe/ZnS quantum dots

    SciTech Connect

    Dneprovskii, V S; Kozlova, M V; Smirnov, A M

    2013-10-31

    We report self-diffraction processes of two types under resonant excitation of the fundamental electron – hole (exciton) transition in a strongly absorbing colloidal solution of CdSe/ZnS quantum dots (QDs) by high-power picosecond laser pulses. In the first case the absorption saturation (bleaching) at the exciton transition frequency and the Stark shift of exciton absorption line lead to the formation of a transparency channel and self-diffraction of the laser beam from the thus induced round diaphragm. In the second case, self-diffraction of two laser beams, intersecting in a cell with a colloidal QD solution, occurs on the diffraction grating induced by these beams. The physical processes responsible for the nonlinear optical properties of CdSe/ZnS QDs and the found selfaction effects are analysed. (nonlinear optical phenomena)

  15. Monitoring aggregate disintegration with laser diffraction: A tool for studying soils as sediments

    NASA Astrophysics Data System (ADS)

    Mason, Joseph; Kasmerchak, Chase; Liang, Mengyu

    2016-04-01

    One of the more important characteristics of soil that becomes hillslope, fluvial, or aeolian sediment is the presences of aggregates, which disintegrate at varying rates and to varying degrees during transport. Laser diffraction particle size analyzers allow monitoring of aggregate disintegration as a sample of soil or sediment suspended in water is circulated continuously through the measurement cell (Bieganowski et al., 2010, Clay Minerals 45-23-34; Mason et al., Catena 87:107-118). Mason et al. (2011) applied this approach to aeolian sedimentary aggregates (e.g. clay pellets eroded from dry lakebeds), immersing dry samples in DI water and circulating them through a Malvern Mastersizer 2000 particle size analyzer for three hours while repeated size distribution (SD) measurements were made. A final measurement was made after sonication and treatment with Na-metaphosphate. In that study, most samples approached a steady SD within three hours, which included both primary mineral grains and persistent aggregates. The disintegration process could be modeled with a first-order rate law representing the disintegration of a single population of aggregates. A wide range of model parameters were observed among the samples studied, and it was suggested that they could be useful in predicting the behavior of these aggregates, under rainfall impact and during slopewash or fluvial transport. Addition of Ca++ to the suspension altered aggregate behavior in some but not all cases. We applied the same method to dry, unground material from upper horizons of soils sampled along a bioclimatic gradient in northern Minnesota, USA, all formed in lithologically similar glacigenic sediment. These ranged from Alfisols (Luvisols) formed under forest since the last deglaciation, to Alfisols under forest that more recently replaced grassland, and Mollisols (Chernozems) that formed entirely under grassland vegetation. Few of these soil samples approached a steady SD within three hours, and

  16. Formation of crownlike and related nanostructures on thin supported gold films irradiated by single diffraction-limited nanosecond laser pulses.

    PubMed

    Kulchin, Yu N; Vitrik, O B; Kuchmizhak, A A; Emel'yanov, V I; Ionin, A A; Kudryashov, S I; Makarov, S V

    2014-08-01

    A type of laser-induced surface relief nanostructure-the nanocrown-on thin metallic films was studied both experimentally and theoretically. The nanocrowns, representing a thin corrugated rim of resolidified melt and resembling well-known impact-induced water-crown splashes, were produced by single diffraction-limited nanosecond laser pulses on thin gold films of variable thickness on low-melting copper and high-melting tungsten substrates, providing different transient melting and adhesion conditions for these films. The proposed model of the nanocrown formation, based on a hydrodynamical (thermocapillary Marangoni) surface instability and described by a Kuramoto-Sivashinsky equation, envisions key steps of the nanocrown appearance and gives qualitative predictions of the acquired nanocrown parameters. PMID:25215830

  17. Simple optical system for manufacturing point diffraction interferometer plates in titanium films using a low intensity CW laser beam

    NASA Astrophysics Data System (ADS)

    Aguilar, Juan C.; Aguilar, J. Félix; Berriel-Valdos, L. R.

    2014-11-01

    We propose an optical system for making pinholes in titanium films for applications in point diffraction interferometry. The optical system for fabrication is easy to implement and to align and, as a result of this, it is possible to obtain pinholes in the range of 1 to 8 μm of diameter. The technique is based on laser ablation and, since we use a green laser, the spot produced by the focus of the optical system can be observed. Also, the damage over the titanium film can be monitored with the aid of a microscope objective lens in real time. The new technique is described and the resulting plates with the pinholes are shown. A successful application of the plates in interferometry is presented as well.

  18. Formation of crownlike and related nanostructures on thin supported gold films irradiated by single diffraction-limited nanosecond laser pulses.

    PubMed

    Kulchin, Yu N; Vitrik, O B; Kuchmizhak, A A; Emel'yanov, V I; Ionin, A A; Kudryashov, S I; Makarov, S V

    2014-08-01

    A type of laser-induced surface relief nanostructure-the nanocrown-on thin metallic films was studied both experimentally and theoretically. The nanocrowns, representing a thin corrugated rim of resolidified melt and resembling well-known impact-induced water-crown splashes, were produced by single diffraction-limited nanosecond laser pulses on thin gold films of variable thickness on low-melting copper and high-melting tungsten substrates, providing different transient melting and adhesion conditions for these films. The proposed model of the nanocrown formation, based on a hydrodynamical (thermocapillary Marangoni) surface instability and described by a Kuramoto-Sivashinsky equation, envisions key steps of the nanocrown appearance and gives qualitative predictions of the acquired nanocrown parameters.

  19. Wavefront correction for near diffraction-limited focal spot on a 6×100 J/1-ns laser facility

    NASA Astrophysics Data System (ADS)

    Fuchs, Julien; Wattellier, Benoit F.; Zou, Ji P.; Chanteloup, Jean-Christophe; Bandulet, H.; Michel, P.; Labaune, C.; Depierreux, S.; Kudryashov, Alexis V.; Aleksandrov, Alexander G.

    2003-10-01

    We have implemented on one beam of the LULI six-beam high-energy (6×100 J, 1 ns) Nd:glass laser facility a closed-loop Adaptive Optics (AO) system to compensate for thermal distortions onto the wave front. Using the AO system composed of a dielectric coated deformable mirror and of a wave front sensor, we are able to improve the wave front quality in order to obtain a focal spot close to the diffraction limit. This allows not only to improve the reproducibility of the experiments but also to increase by at least two orders of magnitude the peak intensity as compared with what usual laser smoothing techniques can achieve.

  20. Plasma heating rate in very intense laser light

    SciTech Connect

    Rashid, S.M.S.

    1982-01-01

    An exact Volkov state solution of the minimally coupled dirac equation is used to calculate the transition rate dR of an electron scattering via a stationary ion in the presence of a very intense laser field. A consistent picture of the scattering is presented in which the electrons' initial and final states are quasi-free states. Accordingly, a modified transition rate dR and a modified Maxwell-Boltzmann distribution are developed. They are used to calculate the heating rate W of a quasi-free plasma in the presence of very intense laser light. In order to simplify the expression for the heating rate W, an important transformation, which changes an infinite sum over Bessel functions into a finite integral, is introdced. It is then shown that the leading term of the heating rate W is similar to the expression of Osborn (with corrections) for intensity I < 10/sup 16/ Watts/cm/sup 2/ Watts/cm/sup 2/ and k/sub B/T < Ike V. A new correction factor is defined to show the effect of very intense laser field when the intensity I > 10/sup 16/ Watts/cm/sup 2/. For k/sub B/T > Ike V, a spin-dependent term of order k/sub B/T/mc/sup 2/ is also discovered. This represents a new term not previously known. It is shown that the effect of this term on the heating rate is substantial and that it is possible to measure its effect with present-day laser systems.

  1. The photoelectric effect and study of the diffraction of light: Two new experiments in UNILabs virtual and remote laboratories network

    NASA Astrophysics Data System (ADS)

    Pedro Sánchez, Juan; Sáenz, Jacobo; de la Torre, Luis; Carreras, Carmen; Yuste, Manuel; Heradio, Rubén; Dormido, Sebastián

    2016-05-01

    This work describes two experiments: "study of the diffraction of light: Fraunhofer approximation" and "the photoelectric effect". Both of them count with a virtual, simulated, version of the experiment as well as with a real one which can be operated remotely. The two previous virtual and remote labs (built using Easy Java(script) Simulations) are integrated in UNILabs, a network of online interactive laboratories based on the free Learning Management System Moodle. In this web environment, students can find not only the virtual and remote labs but also manuals with related theory, the user interface description for each application, and so on.

  2. Rapid production of large-area deep sub-wavelength hybrid structures by femtosecond laser light-field tailoring

    SciTech Connect

    Wang, Lei; Chen, Qi-Dai E-mail: hbsun@jlu.edu.cn; Yang, Rui; Xu, Bin-Bin; Wang, Hai-Yu; Yang, Hai; Huo, Cheng-Song; Tu, Hai-Ling; Sun, Hong-Bo E-mail: hbsun@jlu.edu.cn

    2014-01-20

    The goal of creation of large-area deep sub-wavelength nanostructures by femtosecond laser irradiation onto various materials is being hindered by the limited coherence length. Here, we report solution of the problem by light field tailoring of the incident beam with a phase mask, which serves generation of wavelets. Direct interference between the wavelets, here the first-order diffracted beams, and interference between a wavelet and its induced waves such as surface plasmon polariton are responsible for creation of microgratings and superimposed nanogratings, respectively. The principle of wavelets interference enables extension of uniformly induced hybrid structures containing deep sub-wavelength nanofeatures to macro-dimension.

  3. Spectrum of laser light scattered by nanoparticles in an ablation-induced cavitation bubble

    NASA Astrophysics Data System (ADS)

    Takeuchi, Masato; Sasaki, Koichi

    2016-04-01

    The spectrum of the laser light scattered by nanoparticles in a cavitation bubble, which was induced by laser ablation of a titanium target in water, was measured using a triple-grating spectrograph. The scattered laser light observed at 100 \\upmu s after laser ablation had no wavelength-shifted component, suggesting that nanoparticles at this delay time were metallic. The wavelength-shifted component was observed in the spectrum at a delay time of 200 \\upmu s, suggesting the formation of oxidized nanoparticles. However, we observed no peaks in the spectrum of the scattered laser light in the present in situ laser-light scattering experiment. On the other hand, we observed clear peaks in the Raman spectrum of synthesized nanoparticles. The experimental results suggest slow crystallization of nanoparticles in liquid in liquid-phase laser ablation.

  4. The trickle before the torrent-diffraction data from X-ray lasers.

    PubMed

    Maia, Filipe R N C; Hajdu, Janos

    2016-01-01

    Today Scientific Data launched a collection of publications describing data from X-ray free-electron lasers under the theme 'Structural Biology Applications of X-ray Lasers'. The papers cover data on nanocrystals, single virus particles, isolated cell organelles, and living cells. All data are deposited with the Coherent X-ray Imaging Data Bank (CXIDB) and available to the scientific community to develop ideas, tools and procedures to meet challenges with the expected torrents of data from new X-ray lasers, capable of producing billion exposures per day. PMID:27479637

  5. The trickle before the torrent-diffraction data from X-ray lasers.

    PubMed

    Maia, Filipe R N C; Hajdu, Janos

    2016-08-01

    Today Scientific Data launched a collection of publications describing data from X-ray free-electron lasers under the theme 'Structural Biology Applications of X-ray Lasers'. The papers cover data on nanocrystals, single virus particles, isolated cell organelles, and living cells. All data are deposited with the Coherent X-ray Imaging Data Bank (CXIDB) and available to the scientific community to develop ideas, tools and procedures to meet challenges with the expected torrents of data from new X-ray lasers, capable of producing billion exposures per day.

  6. A geometry for sub-nanosecond X-ray diffraction from laser-shocked polycrystalline foils

    SciTech Connect

    Wark, Justin; Higginbotham, Andrew; Kimminau, Giles; Murphy, William; Nagler, Bob; Whitcher, Thomas; Hawreliak, James; Kalantar, Dan; Butterfield, Martin; El-Dasher, Bassem; McNaney, James; Milathianaki, Despina; Lorenzana, Hector; Remington, Bruce; Davies, Huw; Thornton, Lee; Park, Nigel; Lukezic, Stan

    2007-12-12

    In situ picosecond X-ray diffraction has proved to be a useful tool in furthering our understanding of the response of shocked crystals at the lattice level. To date the vast majority of this work has used single crystals as the shocked samples, owing to their diffraction efficiency, although the study of the response of polycrystalline samples is clearly of interest for many applications. We present here the results of experiments to develop sub-nanosecond powder/polycrystalline diffraction using a cylindrical pinhole camera. By allowing the incident X-ray beam to impinge on the sample at non-normal angles, the response of grains making a variety of angles to the shock propagation direction can potentially be interrogated.

  7. Light pipe design method and stepper experimentation for interference effects reduction in laser illumination

    NASA Astrophysics Data System (ADS)

    Poyet, Jean-Michel; Lutz, Yves

    2016-07-01

    The use of light pipes is an efficient and low-cost technique to get a homogeneous illumination for laser-gated viewing systems. However, this technique suffers from drawbacks when used with coherent sources like solid-state lasers. Compacting light pipe-based laser illuminators involves working with small light pipe sections, and experiments show that interference fringes appear on the laser illumination profiles. The principle of light pipe homogenization has been reviewed using geometrical optics to understand the phenomenon better, and a pragmatic light pipe design method, based on laser-gated viewing system parameters, is proposed. Another original solution based on optical stepper is studied to reduce both interference fringes and speckle noise to increase the homogeneity of laser illumination profiles.

  8. Modeling laser beam diffraction and propagation by the mode-expansion method.

    PubMed

    Snyder, James J

    2007-08-01

    In the mode-expansion method for modeling propagation of a diffracted beam, the beam at the aperture can be expanded as a weighted set of orthogonal modes. The parameters of the expansion modes are chosen to maximize the weighting coefficient of the lowest-order mode. As the beam propagates, its field distribution can be reconstructed from the set of weighting coefficients and the Gouy phase of the lowest-order mode. We have developed a simple procedure to implement the mode-expansion method for propagation through an arbitrary ABCD matrix, and we have demonstrated that it is accurate in comparison with direct calculations of diffraction integrals and much faster.

  9. The Measurement of the Speed of Light Using a Laser Pointer.

    ERIC Educational Resources Information Center

    Mak, Se-yuen; Yip, Din-yan

    2000-01-01

    Presents a method for measuring the speed of light using a laser pointer with adjustable focus as the signal carrier, a signal generator to modulate the light beam, and a student oscilloscope to detect the phase shift. (Author/CCM)

  10. Vectorial algorithm for the computation of light propagation equation based on Huygens' principle using the scalar theory of diffraction

    NASA Astrophysics Data System (ADS)

    Morucci, Stephane; Noirard, Pierre; Grossetie, Jean-Claude

    1996-03-01

    In digital holography, computation of holograms is often reduced to calculations of fast Fourier transforms if the distance between the object plane and the hologram plane is large enough. Two classical approximations for solving this problem include a binomial series expansion of the distance and an elimination of the so-called inclination factor. We present here a vectorial algorithm which computes the discrete form of the light propagation equation obtained by the Huygens' principle for a bidimensional object. None of the approximations mentioned above have been used. This enables the computation of a diffraction pattern at any distance compatible with the scalar theory of diffraction. This vectorial algorithm has been implemented on workstations, on a Convex C-220 and on a Cray YMP computer. We focus our attention on the computing granularity of the problem and we present processing times and the associated performances for bidimensional images. Various holograms are computed and compared with those obtained by two traditional methods, namely, Fresnel transforms and the resolution of the rigorous scalar diffraction equation using discrete convolutions. We then consider the 3D case and modifications are proposed in order to parallelize this algorithm.

  11. Measuring Slit Width and Separation in a Diffraction Experiment

    ERIC Educational Resources Information Center

    Gan, K. K.; Law, A. T.

    2009-01-01

    We present a procedure for measuring slit width and separation in single- and double-slit diffraction experiments. Intensity spectra of diffracted laser light are measured with an optical sensor (PIN diode). Slit widths and separations are extracted by fitting to the measured spectra. We present a simple fitting procedure to account for the…

  12. Macromolecular structures probed by combining single-shot free-electron laser diffraction with synchrotron coherent X-ray imaging.

    PubMed

    Gallagher-Jones, Marcus; Bessho, Yoshitaka; Kim, Sunam; Park, Jaehyun; Kim, Sangsoo; Nam, Daewoong; Kim, Chan; Kim, Yoonhee; Noh, Do Young; Miyashita, Osamu; Tama, Florence; Joti, Yasumasa; Kameshima, Takashi; Hatsui, Takaki; Tono, Kensuke; Kohmura, Yoshiki; Yabashi, Makina; Hasnain, S Samar; Ishikawa, Tetsuya; Song, Changyong

    2014-01-01

    Nanostructures formed from biological macromolecular complexes utilizing the self-assembly properties of smaller building blocks such as DNA and RNA hold promise for many applications, including sensing and drug delivery. New tools are required for their structural characterization. Intense, femtosecond X-ray pulses from X-ray free-electron lasers enable single-shot imaging allowing for instantaneous views of nanostructures at ambient temperatures. When combined judiciously with synchrotron X-rays of a complimentary nature, suitable for observing steady-state features, it is possible to perform ab initio structural investigation. Here we demonstrate a successful combination of femtosecond X-ray single-shot diffraction with an X-ray free-electron laser and coherent diffraction imaging with synchrotron X-rays to provide an insight into the nanostructure formation of a biological macromolecular complex: RNA interference microsponges. This newly introduced multimodal analysis with coherent X-rays can be applied to unveil nano-scale structural motifs from functional nanomaterials or biological nanocomplexes, without requiring a priori knowledge.

  13. Macromolecular structures probed by combining single-shot free-electron laser diffraction with synchrotron coherent X-ray imaging.

    PubMed

    Gallagher-Jones, Marcus; Bessho, Yoshitaka; Kim, Sunam; Park, Jaehyun; Kim, Sangsoo; Nam, Daewoong; Kim, Chan; Kim, Yoonhee; Noh, Do Young; Miyashita, Osamu; Tama, Florence; Joti, Yasumasa; Kameshima, Takashi; Hatsui, Takaki; Tono, Kensuke; Kohmura, Yoshiki; Yabashi, Makina; Hasnain, S Samar; Ishikawa, Tetsuya; Song, Changyong

    2014-01-01

    Nanostructures formed from biological macromolecular complexes utilizing the self-assembly properties of smaller building blocks such as DNA and RNA hold promise for many applications, including sensing and drug delivery. New tools are required for their structural characterization. Intense, femtosecond X-ray pulses from X-ray free-electron lasers enable single-shot imaging allowing for instantaneous views of nanostructures at ambient temperatures. When combined judiciously with synchrotron X-rays of a complimentary nature, suitable for observing steady-state features, it is possible to perform ab initio structural investigation. Here we demonstrate a successful combination of femtosecond X-ray single-shot diffraction with an X-ray free-electron laser and coherent diffraction imaging with synchrotron X-rays to provide an insight into the nanostructure formation of a biological macromolecular complex: RNA interference microsponges. This newly introduced multimodal analysis with coherent X-rays can be applied to unveil nano-scale structural motifs from functional nanomaterials or biological nanocomplexes, without requiring a priori knowledge. PMID:24786694

  14. Camera for coherent diffractive imaging and holography with a soft-x-ray free-electron laser.

    PubMed

    Bajt, Sasa; Chapman, Henry N; Spiller, Eberhard A; Alameda, Jennifer B; Woods, Bruce W; Frank, Matthias; Bogan, Michael J; Barty, Anton; Boutet, Sebastien; Marchesini, Stefano; Hau-Riege, Stefan P; Hajdu, Janos; Shapiro, David

    2008-04-01

    We describe a camera to record coherent scattering patterns with a soft-x-ray free-electron laser (FEL). The camera consists of a laterally graded multilayer mirror, which reflects the diffraction pattern onto a CCD detector. The mirror acts as a bandpass filter for both the wavelength and the angle, which isolates the desired scattering pattern from nonsample scattering or incoherent emission from the sample. The mirror also solves the particular problem of the extreme intensity of the FEL pulses, which are focused to greater than 10(14) W/cm2. The strong undiffracted pulse passes through a hole in the mirror and propagates onto a beam dump at a distance behind the instrument rather than interacting with a beam stop placed near the CCD. The camera concept is extendable for the full range of the fundamental wavelength of the free electron laser in Hamburg (FLASH) FEL (i.e., between 6 and 60 nm) and into the water window. We have fabricated and tested various multilayer mirrors for wavelengths of 32, 16, 13.5, and 4.5 nm. At the shorter wavelengths mirror roughness must be minimized to reduce scattering from the mirror. We have recorded over 30,000 diffraction patterns at the FLASH FEL with no observable mirror damage or degradation of performance.

  15. A camera for coherent diffractive imaging and holography with a soft-X-ray free electron laser

    SciTech Connect

    Bajt, S; Chapman, H N; Spiller, E; Alameda, J; Woods, B; Frank, M; Bogan, M J; Barty, A; Boutet, S; Marchesini, S; Hau-Riege, S P; Hajdu, J; Shapiro, D

    2007-09-24

    We describe a camera to record coherent scattering patterns with a soft-X-ray free-electron laser. The camera consists of a laterally-graded multilayer mirror which reflects the diffraction pattern onto a CCD detector. The mirror acts as a bandpass filter both for wavelength and angle, which isolates the desired scattering pattern from non-sample scattering or incoherent emission from the sample. The mirror also solves the particular problem of the extreme intensity of the FEL pulses, which are focused to greater than 10{sup 14} W/cm{sup 2}. The strong undiffracted pulse passes through a hole in the mirror and propagates on to a beam dump at a distance behind the instrument rather than interacting with a beamstop placed near the CCD. The camera concept is extendable for the full range of the fundamental wavelength of the FLASH FEL (i.e. between 6 nm and 60 nm) and into the water window. We have fabricated and tested various multilayer mirrors for wavelengths of 32 nm, 16 nm, 13.5 nm, and 4.5 nm. At the shorter wavelengths mirror roughness must be minimized to reduce scattering from the mirror. We have recorded over 30,000 diffraction patterns at the FLASH free-electron laser with no observable mirror damage or degradation of performance.

  16. Measurement of yarn twist based on backward light scattering and small-angle far-field diffraction

    NASA Astrophysics Data System (ADS)

    Pei, Z. G.; Tao, X. M.

    2015-12-01

    This paper presents a non-destructive, non-contact method for measuring the twist of a yarn based on light scattering and diffraction. The surface twist angle is measured by determining the direction of the line with the highest intensity on the backward light scattering pattern which is perpendicular to the surface fibers, which is verified by both theoretical analysis based on Beckmann’s scattering model and experiments. The yarn diameter is measured with good accuracy by using the small-angle far-field diffraction pattern of the yarn body. Yarn twist is then derived from the measured surface twist angle and yarn diameter. Further studies reveal that the measured yarn twists by the proposed method are comparable to those measured based on microscopic images of the yarn. This method requires no high-magnification optics and is able to pick up short-term variations of twist with less labor intensity, indicating its potential application in the on-line measuring of yarn twist and its distribution.

  17. Optimal illumination of phase-only diffractive element using GPC light shaper

    NASA Astrophysics Data System (ADS)

    Villangca, Mark; Bañas, Andrew; Kopylov, Oleksii; Palima, Darwin; Glückstad, Jesper

    2015-03-01

    We have previously proposed and demonstrated optimal beam shaping of contiguous light patterns using the Generalized Phase Contrast (GPC) method. The concept has been packaged into a compact add-on module, which we call the GPC light shaper (LS) that can be conveniently integrated to existing optical setups requiring optimal illumination of devices such as spatial light modulators (SLMs). In this work, we integrated the GPC LS into a holography setup to generate more intense focal spots and extended patterns. The output of the holography setup with the GPC LS is compared with a similar setup but using only hard-truncated beams. Our results show that, we get a ~3x gain in intensity of the generated patterns when using GPC LS.

  18. Large-angle Programmable Direct Laser Interference Patterning with Ultrafast Laser Using Spatial Light Modulator

    NASA Astrophysics Data System (ADS)

    Knorr, Fabian; Uyttendaele, Andreas; Stauch, Julian; Schechtel, Florian; Reg, Yvonne; Zimmermann, Maik

    Direct laser interference patterning (DLIP) facilitates the creation of periodic micro- and nanostructures for numerous applications such as anti-reflective moth-eye structures, security features (holograms) or for surface topology modification. For high quality applications the use of ultrafast laser sources is demanded. However, this puts high requirements on laser system technology as the short pulses imply very short spatial interaction lengths. Furthermore flexible adjustment of the patterns to be generated is preferable which is difficult with most opto-mechanical setups. We present an approach using a spatial light modulator (SLM) for the creation of flexibly programmable DLIP-patterns. With our optical setup we are able to overcome the limitations the SLM poses at the current state of the art, thus achieving 45°-90° interference angles of two-, three- and four-beam interference patterns. We show regular structure sizes of ≈1 μm inscribed on the surface of polished metallic substrates with a 12 picosecond laser source at a wavelength of 1064 nm.

  19. Fabrication of waveguide spatial light modulators via femtosecond laser micromachining

    NASA Astrophysics Data System (ADS)

    Savidis, Nickolaos; Jolly, Sundeep; Datta, Bianca; Karydis, Thrasyvoulos; Bove, V. M.

    2016-03-01

    We have previously introduced an anisotropic leaky-mode modulator as a waveguide-based, acousto-optic solution for spatial light modulation in holographic video display systems. Waveguide fabrication for these and similar surface acoustic wave devices relies on proton exchange of a lithium niobate substrate, which involves the immersion of the substrate in an acid melt. While simple and effective, waveguide depth and index profiles resulting from proton exchange are often non-uniform over the device length or inconsistent between waveguides fabricated at different times using the same melt and annealing parameters. In contrast to proton exchange, direct writing of waveguides has the appeal of simplifying fabrication (as these methods are inherently maskless) and the potential of fine and consistent control over waveguide depth and index profiles. In this paper, we explore femtosecond laser micromachining as an alternative to proton exchange in the fabrication of waveguides for anisotropic leaky-mode modulators.

  20. Development of a versatile laser light scattering instrument

    NASA Technical Reports Server (NTRS)

    Meyer, William V.; Ansari, Rafat R.

    1990-01-01

    A versatile laser light scattering (LLS) instrument is developed for use in microgravity to measure microscopic particles of 30 A to above 3 microns. Since it is an optical technique, LLS does not affect the sample being studied. A LLS instrument built from modules allows several configurations, each optimized for a particular experiment. The multiangle LLS instrument can be mounted in the rack in the Space Shuttle and on Space Station Freedom. It is possible that a Space Shuttle glove-box and a lap-top computer containing a correlator card can be used to perform a number of experiments and to demonstrate the technology needed for more elaborate investigations. This offers simple means of flying a great number of experiments without the additional requirements of full-scale flight hardware experiments.

  1. Diffraction-Enhanced Computed Tomographic Imaging of Growing Piglet Joints by Using a Synchrotron Light Source

    PubMed Central

    Rhoades, Glendon W; Belev, George S; Chapman, L Dean; Wiebe, Sheldon P; Cooper, David M; Wong, Adelaine TF; Rosenberg, Alan M

    2015-01-01

    The objective of this project was to develop and test a new technology for imaging growing joints by means of diffraction-enhanced imaging (DEI) combined with CT and using a synchrotron radiation source. DEI–CT images of an explanted 4-wk-old piglet stifle joint were acquired by using a 40-keV beam. The series of scanned slices was later ‘stitched’ together, forming a 3D dataset. High-resolution DEI-CT images demonstrated fine detail within all joint structures and tissues. Striking detail of vasculature traversing between bone and cartilage, a characteristic of growing but not mature joints, was demonstrated. This report documents for the first time that DEI combined with CT and a synchrotron radiation source can generate more detailed images of intact, growing joints than can currently available conventional imaging modalities. PMID:26310464

  2. Time-resolved spectral investigations of laser light induced microplasma

    NASA Astrophysics Data System (ADS)

    Nánai, L.; Hevesi, I.

    1992-01-01

    The dynamical and spectral properties of an optical breakdown microplasma created by pulses of different lasers on surfaces of insulators (KCI), metals (Cu) and semiconductors (V 2O 5), have been investigated. Experiments were carried out in air and vacuum using different wavelengths (λ = 0.694μm, type OGM-20,λ = 1.06μm with a home-made laser based on neodymium glass crystal, and λ = 10.6μm, similarly home-made) and pulse durations (Q-switched and free-running regimes). To follow the integral, dynamical and spectral characteristics of the luminous spot of microplasma we have used fast cameras (SFR-2M, IMACON-HADLAND), a high speed spectral camera (AGAT-2) and a spectrograph (STE-1). It has been shown that the microplasma consists of two parts: fast front (peak) with τ≈100 ns and slow front (tail) with τ≈1μs durations. The detonation front speed is of the order of ≈10 5 cm s -1 and follows the temporal dependence of to t0.4. It depends on the composition of the surrounding gas and its pressure and could be connected with quick evaporation of the material investigated (peak) and optical breakdown of the ambient gaseous atmosphere (tail). From the delay in appearance of different characteristic spectral lines of the target material and its gaseous surrounding we have shown that the evolution of the microplasma involves evaporation and ionization of the atoms of the parent material followed by optical breakdown due to the incident and absorbed laser light, together with microplasma expansion.

  3. Invitation to the World of the Plasma for Light Source 3.Light Source Measurement 3.1 Laser Diagnostics of Plasmas for Light Sources

    NASA Astrophysics Data System (ADS)

    Motomura, Hideki; Jinno, Masafumi

    Examples and basic theories of various methods of laser diagnostics of plasmas for light sources are introduced. Most introduced papers were presented at International Symposium on the Science and Technology of Light Sources (LS), which is the only international symposium on the science and technology of light sources.

  4. Coherent X-Ray Diffraction Imaging of Chloroplasts from Cyanidioschyzon merolae by Using X-Ray Free Electron Laser.

    PubMed

    Takayama, Yuki; Inui, Yayoi; Sekiguchi, Yuki; Kobayashi, Amane; Oroguchi, Tomotaka; Yamamoto, Masaki; Matsunaga, Sachihiro; Nakasako, Masayoshi

    2015-07-01

    Coherent X-ray diffraction imaging (CXDI) is a lens-less technique for visualizing the structures of non-crystalline particles with the dimensions of submicrometer to micrometer at a resolution of several tens of nanometers. We conducted cryogenic CXDI experiments at 66 K to visualize the internal structures of frozen-hydrated chloroplasts of Cyanidioschyzon merolae using X-ray free electron laser (XFEL) as a coherent X-ray source. Chloroplast dispersed specimen disks at a number density of 7/(10×10 µm(2)) were flash-cooled with liquid ethane without staining, sectioning or chemical labeling. Chloroplasts are destroyed at atomic level immediately after the diffraction by XFEL pulses. Thus, diffraction patterns with a good signal-to-noise ratio from single chloroplasts were selected from many diffraction patterns collected through scanning specimen disks to provide fresh specimens into the irradiation area. The electron density maps of single chloroplasts projected along the direction of the incident X-ray beam were reconstructed by using the iterative phase-retrieval method and multivariate analyses. The electron density map at a resolution of 70 nm appeared as a C-shape. In addition, the fluorescence image of proteins stained with Flamingo™ dye also appeared as a C-shape as did the autofluorescence from Chl. The similar images suggest that the thylakoid membranes with an abundance of proteins distribute along the outer membranes of chloroplasts. To confirm the present results statistically, a number of projection structures must be accumulated through high-throughput data collection in the near future. Based on the results, we discuss the feasibility of XFEL-CXDI experiments in the structural analyses of cellular organelles.

  5. Particle-in-cell simulations of hot electron generation using defocused laser light in cone targets

    NASA Astrophysics Data System (ADS)

    Yang, Lei; Pasley, John

    2016-08-01

    The effects of defocusing a high intensity pulse of laser light on the generation of hot electrons in a cone are investigated using particle-in-cell simulations. The results indicate that defocused laser light can soften the electron energy spectrum and increase the coupling efficiency compared to the use of a laser in tight focus. It is shown that this is a consequence of the density profile of plasma produced by the laser prepulse, which is less dense in the case of the defocused laser. The relevance of this result to fast ignition inertial confinement fusion is discussed.

  6. Strong visible light emission from well-aligned multiwalled carbon nanotube films under infrared laser irradiation

    SciTech Connect

    Zhang Yong; Gong Tao; Liu Wenjin; Zhang Xianfeng; Chang Jianguo; Wang Kunlin; Wu Dehai

    2005-10-24

    We report strong and brilliant visible light emission from well-aligned multiwalled carbon nanotube (AMWNT) films under infrared (IR) laser irradiation with wavelength at 1.06 and 10.6 {mu}m, respectively. The AMWNT film shows a high durability against laser irradiation and achieved a conversion from IR laser to visible light. It is a good candidate for optical converter. Light emission spectra versus different wavelengths and various powers were found to have similar line shapes. It could be explained as combination of laser-induced photoluminescence and resistive heating.

  7. The trickle before the torrent—diffraction data from X-ray lasers

    PubMed Central

    Maia, Filipe R.N.C.; Hajdu, Janos

    2016-01-01

    Today Scientific Data launched a collection of publications describing data from X-ray free-electron lasers under the theme ‘Structural Biology Applications of X-ray Lasers’. The papers cover data on nanocrystals, single virus particles, isolated cell organelles, and living cells. All data are deposited with the Coherent X-ray Imaging Data Bank (CXIDB) and available to the scientific community to develop ideas, tools and procedures to meet challenges with the expected torrents of data from new X-ray lasers, capable of producing billion exposures per day. PMID:27479637

  8. Fresnel and Fraunhofer diffraction of a Gaussian laser beam by fork-shaped gratings.

    PubMed

    Janicijevic, Ljiljana; Topuzoski, Suzana

    2008-11-01

    Expressions describing the vortex beams that are generated by the process of Fresnel diffraction of a Gaussian beam incident out of waist on fork-shaped gratings of arbitrary integer charge p, and vortex spots in the case of Fraunhofer diffraction by these gratings, are deduced. The common general transmission function of the gratings is defined and specialized for the cases of amplitude holograms, binary amplitude gratings, and their phase versions. Optical vortex beams, or carriers of phase singularity with charges mp and -mp, are the higher negative and positive diffraction-order beams. The radial part of their wave amplitudes is described by the product of the mpth-order Gauss-doughnut function and a Kummer function, or by the first-order Gauss-doughnut function and the difference of two modified Bessel functions whose orders do not match the singularity charge value. The wave amplitude and the intensity distributions are discussed for the near and far fields in the focal plane of a convergent lens, as well as the specialization of the results when the grating charge p=0; i.e., the grating turns from forked into rectilinear. The analytical expressions for the vortex radii are also discussed.

  9. OPTICAL WAVEPACKETS (OPTICAL BULLETS): A NEW DIFFRACTION FREE FORM OF LIGHT TRAVEL

    SciTech Connect

    D. FUNK; J. NICHOLSON; ET AL

    1999-09-01

    This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). We conducted studies of the propagation of self-confined packets of light or ''Optical Bullets'' through air. These packets are self-forming and require no active optics. At the present time, theoretical explanations provide an incomplete description of this process. Generation of these pulses requires a light source of sufficient energy and with a short enough pulse-width that the intensity exceeds a critical wavelength dependent value. We used a Ti:Sapphire based system to generate the pulses and we observed pulse-splitting and chirp-dependent control of the formation of these filaments. In addition, we developed a novel algorithm for extracting the phase and electric field of these pulses using Frequency Resolved Optical Gating coupled to genetic algorithms for pulse retrieval.

  10. Controllable light diffraction in woodpile photonic crystals filled with liquid crystal

    SciTech Connect

    Ho, Chih-Hua; Zeng, Hao; Wiersma, Diederik S.; Cheng, Yu-Chieh; Maigyte, Lina; Trull, Jose; Cojocaru, Crina; Staliunas, Kestutis

    2015-01-12

    An approach to switching between different patterns of light beams transmitted through the woodpile photonic crystals filled with liquid crystals is proposed. The phase transition between the nematic and isotropic liquid crystal states leads to an observable variation of the spatial pattern transmitted through the photonic structure. The transmission profiles in the nematic phase also show polarization sensibility due to refractive index dependence on the field polarization. The experimental results are consistent with a numerical calculation by Finite Difference Time Domain method.

  11. Reversibly Trapping Visible Laser Light through the Catalytic Photo-oxidation of I(-) by Ru(bpy)3(2+).

    PubMed

    Morim, Derek R; Vargas-Baca, Ignacio; Saravanamuttu, Kalaichelvi

    2016-04-21

    A Gaussian, visible laser beam traveling in a hydrogel doped with NaI and Ru(bpy)3Cl2 spontaneously transforms into a localized, self-trapped beam, which propagates without diverging through the medium. The catalytic, laser-light-induced oxidation of I(-) by [Ru(bpy)3](2+) generates I3(-) species, which create a refractive index increase along the beam path. The result is a cylindrical waveguide, which traps the optical field as bound modes and suppresses natural diffraction. When the beam is switched off, diffusion of I3(-) erases the waveguide within minutes and the system reverts to its original composition, enabling regeneration of the self-trapped beam. Our findings demonstrate reversible self-trapping for the first time in a precisely controllable, molecular-level photoreaction and could open routes to circuitry-free photonics devices powered by the interactions of switchable self-trapped beams. PMID:27035609

  12. Planar Sauter Mean Diameter measurements in liquid centered swirl coaxial injector using Laser Induced Fluorescence, Mie scattering and laser diffraction techniques

    NASA Astrophysics Data System (ADS)

    Kannaiyan, Kamalakannan; Banda, Manoj Venkata Krishna; Vaidyanathan, Aravind

    2016-06-01

    An experimental technique is carried out to demonstrate the measurement of planar Sauter Mean Diameter (SMD or D32) distribution in a liquid centered swirl coaxial injector (LCSC) using simultaneous measurements of Mie scattering, Planar Laser-Induced Fluorescence (PLIF) and Laser diffraction technique (LDT). Here water is used as the test fluid with addition of optimized quantities of the organic dye (Rhodamine 6 g) for PLIF measurements. Experiments are carried out at three experimental conditions with momentum flux ratios of 6.25, 12.14, and 19.95 respectively. Experiments are carried out to study the effect of dye concentration in LDT. LDT (line of sight) is corrected for multiple scattering effects. The SMD distribution obtained from Liquid Sheet Drop Sizing (LSDS) technique is calibrated using LDT (Malvern particle analyzer) that utilizes the principle of diffraction; the results obtained from both the methods are compared and analyzed using the respective histograms. The variations in the distribution of droplet diameter along the axial and radial locations in the spray field are also studied in detail.

  13. High-power ({gt}0.9 W cw) diffraction-limited semiconductor laser based on a fiber Bragg grating external cavity

    SciTech Connect

    Cornwell, D.M. , Jr.; Thomas, H.J.

    1997-02-01

    We have developed a high-power ({gt}0.9 W cw) diffraction-limited semiconductor laser based on a tapered semiconductor optical amplifier using a fiber Bragg grating in an external cavity configuration. Frequency-selective feedback from the fiber grating is injected into the amplifier via direct butt coupling through a single mode fiber, resulting in a spectrally stable and narrow ({lt}0.3 nm) high-power laser for solid-state laser pumping, laser remote sensing, and optical communications. {copyright} {ital 1997 American Institute of Physics.}

  14. Prospect for feedback guided surgery with ultra-short pulsed laser light.

    PubMed

    Jeong, Diana C; Tsai, Philbert S; Kleinfeld, David

    2012-02-01

    The controlled cutting of tissue with laser light is a natural technology to combine with automated stereotaxic surgery. A central challenge is to cut hard tissue, such as bone, without inducing damage to juxtaposed soft tissue, such as nerve and dura. We review past work that demonstrates the feasibility of such control through the use of ultrafast laser light to both cut and generate optical feedback signals via second harmonic generation and laser induced plasma spectra.

  15. Hybrid refractive/diffractive optical system design for light and compact uncooled longwave infrared imager

    NASA Astrophysics Data System (ADS)

    Wang, Hu; Bai, Yu; Luo, Jianjun

    2012-10-01

    Compares with traditional optics,the difractive optical element(DOE) has unique property of minus dispersion.The special state can be used in the optical system to improve performance,lighten weight and reduce volume effectively.In the paper,an infrared optical system with DOE for LWIR thermal imager is proposed.The primary optical parameters of thermal imager are wavelength range 8.0- 12.0μm,effective focal length (EFL) 150 mm,f/numbe 1.0 and field of view 8.58 degrees.The system uses uncooled infrared detector with 320×240 pixels and 45μm pixel size. The f/number matches the sensitivity range of detector array. The infrared optical system is designed by CODE-V optical design software.It is consisted of two lens,the materials of the two lenses are Germanium.The DOE is fabricated on the convex of the first lens and it can be fabricated by diamond turning technology.The imaging quafity of the optical system approached to diffraction limit.The value of modulation transfer function (MTF) at Nyquist frequency(11lp/mm) is great than 0.78.

  16. Tomographic incoherent phase imaging, a diffraction tomography alternative for any white-light microscope

    NASA Astrophysics Data System (ADS)

    Bon, Pierre; Aknoun, Shérazade; Savatier, Julien; Wattellier, Benoit; Monneret, Serge

    2013-02-01

    In this paper, we discuss the possibility of making tomographic reconstruction of the refractive index of a microscopic sample using a quadriwave lateral shearing interferometer, under incoherent illumination. A Z-stack is performed and the acquired incoherent elecromagnetic fields are deconvoluted before to retrieve in a quantitative manner the refractive index. The results are presented on polystyrene beads and can easily be expanded to biological samples. This technique is suitable to any white-light microscope equipped with nanometric Z-stack module.

  17. Direct laser interference patterning of polystyrene films doped with azo dyes, using 355 nm laser light

    NASA Astrophysics Data System (ADS)

    Broglia, M. F.; Suarez, S.; Soldera, F.; Mücklich, F.; Barbero, C. A.; Bellingeri, R.; Alustiza, F.; Acevedo, D.

    2014-05-01

    The generation of line-like periodic patterns by direct laser interference patterning (DLIP) of polystyrene films (PS) at a wavelength of 355 nm has been investigated. No structuration is achieved in plain PS due to the weak absorption of the polymer at 355 nm. On the other hand, patterning is achieved on films doped (PSd) with an azo dye (2-anisidine → 2-anisidine) which is incorporated in the polymer solution used for film preparation. Periodic micro-structures are generated. DLIP on PSd results in the swelling of the surface at low fluences, while at high laser intensities it causes the ablation of the regions at the interference maxima positions. The results contrast with the usual process of DLIP on PS (at shorter wavelengths, like 266 nm) where only ablation is detected. The results suggest that decomposition of the azo dye is the driving force of the patterning which therefore differ from the patterning obtained when plain PS is irradiated with laser light able to be absorbed by the aromatic ring in PS (e.g. 266 nm). The biocompatibility of these materials and adhesion of cells was tested, the data from in vitro assays shows that fibroblast cells are attached and proliferate extensively on the PSd films.

  18. Fabrication of broadband antireflective black metal surfaces with ultra-light-trapping structures by picosecond laser texturing and chemical fluorination

    NASA Astrophysics Data System (ADS)

    Zheng, Buxiang; Wang, Wenjun; Jiang, Gedong; Mei, Xuesong

    2016-06-01

    A hybrid method consisting of ultrafast laser-assisted texturing and chemical fluorination treatment was applied for efficiently enhancing the surface broadband antireflection to fabricate black titanium alloy surface with ultra-light-trapping micro-nanostructure. Based on the theoretical analysis of surface antireflective principle of micro-nanostructures and fluoride film, the ultra-light-trapping micro-nanostructures have been processed using a picosecond pulsed ultrafast laser on titanium alloy surfaces. Then fluorination treatment has been performed by using fluoroalkyl silane solution. According to X-ray diffraction phase analysis of the surface compositions and measurement of the surface reflectance using spectrophotometer, the broadband antireflective properties of titanium alloy surface with micro-nano structural characteristics were investigated before and after fluorination treatment. The results show that the surface morphology of micro-nanostructures processed by picosecond laser has significant effects on the antireflection of light waves to reduce the surface reflectance, which can be further reduced using chemical fluorination treatment. The high antireflection of over 98 % in a broad spectral range from ultraviolet to infrared on the surface of metal material has been achieved for the surface structures, and the broadband antireflective black metal surfaces with an extremely low reflectance of ultra-light-trapping structures have been obtained in the wavelength range from ultraviolet-visible to near-infrared, middle-wave infrared. The average reflectance of microgroove groups structured surface reaches as low as 2.43 % over a broad wavelength range from 200 to 2600 nm. It indicates that the hybrid method comprising of picosecond laser texturing and chemical fluorination can effectively induce the broadband antireflective black metal surface. This method has a potential application for fabricating antireflective surface used to improve the

  19. Diffraction-limited soft-x-ray projection imaging using a laser plasma source

    SciTech Connect

    Tichenor, D.A.; Kubiak, G.D.; Malinowski, M.E.; Stulen, R.H.; Haney, S.J.; Berger, K.W.; Brown, L.A. ); Freeman, R.R.; Mansfield, W.M.; Wood, O.R. II; Tennant, D.M.; Bjorkholm, J.E.; MacDowell, A.A. ); Bokor, J.; Jewell, T.E.; White, D.L.; Windt, D.L.; Waskiewicz, W.K. )

    1991-10-15

    Projection imaging of 0.1-{mu}m lines and spaces is demonstrated with a Mo/Si multilayer coated Schwarzschild objective and 14-nm illumination from a laser plasma source. This structure has been etched into a silicon wafer by using a trilevel resist and reactive ion etching. Low-contrast modulation at 0.05-{mu}m lines and spaces is observed in polymethylmethacrylate.

  20. A new 3D shape precision measurement system calibration method based on non-diffraction grating structured light projection

    NASA Astrophysics Data System (ADS)

    Zhu, Ya; Zhou, Liping; Li, Wenlong; Gan, Jianghong; Xu, Long

    2016-03-01

    Phase calculation-based fringe projection techniques are widely used in three-dimensional shape measurement fields to obtain the 3D shape data of the object's surface. One important step of the phase calculation is calibration, which determines the relationship between the image phase and depth information. The traditional calibration methods are too complex and require many parameters. In this paper, model of 3D shape precision calibration method based on non-diffraction grating structured light fringes projection is proposed, which is consist of camera model, fringe phase obtaining, height-phase relationship model. This method is simple, convenient and there is no approximation in it, which can satisfy the precision measurement.

  1. Interaction of the focused laser beam with the grooved surface of optical disk: Evanescent coupling and vector diffraction effects

    NASA Astrophysics Data System (ADS)

    Yeh, Wei-Hung

    1999-10-01

    The primary objective of this dissertation is to present a clear physical picture and useful insights of polarization effects in the diffraction of focused beams by grooved, multilayer-coated disks. The reading process of optical disk systems significantly relies on the reaction of the incident focused beam to the disk structure, may it be the groove profile or coating materials. The resulting complex-amplitude from diffraction is the main source for the readout signal. In the presence of the periodic pattern and the focused beam, however, different polarization states usually result in different complex-amplitudes. A good understanding of polarization effects in grooved multilayer disks is thus required for the optimum design of optical data storage systems. The pursuit of high-density recording inevitably drives the optical data storage industry to reduce the wavelength of light sources, decrease the track pitch of optical disks, and increase the numerical aperture of objective lenses. The track pitch and the size of the focused spot gradually approach the optical wavelength. Under these circumstances, the analysis of the interaction of focused beams with this type of high- frequency periodic disk using conventional scalar diffraction theory is no longer adequate. Only through vector diffraction study of polarization effects in the interaction of the focused beam with the periodic pattern can the characteristics of an optical disk system be fully understood and improved. Starting from the introduction of various polarization effects in optical disk systems and basic concepts of both scalar and vector diffraction theory, we then focus on the studies of diffraction patterns at the exit pupil of the objective lens and on the disk surface. Different behavior on the baseball pattern and in the effective groove depth is observed for the two polarization states. The use of the solid immersion lens to extensively increase the area density of optical disk systems prompts

  2. Light-induced scattering in laser radiation nonlinear optical limiting based on fullerene-containing media

    NASA Astrophysics Data System (ADS)

    Belousova, Inna M.; Grigor'ev, Vladimir A.; Danilov, Oleg B.; Kalintsev, Alexander G.; Kris'ko, A. V.; Mironova, N. G.; Yur'ev, Michail S.

    2001-03-01

    The contribution of light induced scattering to nonlinear optical limiting is theoretically and experimentally investigated. It is shown that light induced scattering is caused by fine-scale (1 divided by 10 micrometer) inhomogeneities formation, very low (comparable to spontaneous noise) laser beam inhomogeneities can evolve into light induced scattering. The numerical modeling of scattered radiation angular distribution and laser radiation attenuation in optical limiters was performed. The modeling results were compared with the experimental ones.

  3. NEW ACTIVE MEDIA AND ELEMENTS OF LASER SYSTEMS: Simulation of Fresnel diffraction of output beams of unstable resonators

    NASA Astrophysics Data System (ADS)

    Cherepenin, N. D.; Usanov, Yu Ya

    1987-11-01

    The solution is given of the problem of diffraction of a spherical wave by an aperture in the form of a doubly connected region with a rectangular or circular contour, followed by the propagation of this wave across an optical system characterized by an arbitrary ray matrix. The exact expression is obtained for the Fresnel-Kirchhoff integral in terms of Fresnel integrals or Lommel functions of two variables. An investigation is made of the evolution of the effective beam width when its effective length and the shape of the aperture altered. A simple method is proposed for applying this solution in approximate simulation of the distribution of the field in laser output beams generated in unstable optical resonators.

  4. Physicochemical bases of differences between the sedimentometric and laser-diffraction techniques of soil particle-size analysis

    NASA Astrophysics Data System (ADS)

    Fedotov, G. N.; Shein, E. V.; Putlyaev, V. I.; Arkhangel'Skaya, T. A.; Eliseev, A. V.; Milanovskii, E. Yu.

    2007-03-01

    Comparison of the particle-size distributions in different soils showed that the sedimentation method (Kachinskii pipette method) gives higher (by 1.5-5 times) values of the clay content than the laser diffraction method. This is related to the significant variation in density of soil solids, which is taken to be constant in the sedimentation method. Therefore, particles of significantly larger size and lower density fall into this fraction. Using optical, electron, and confocal microscopy, it was shown that the low density of soil particles of silt size falling into the sedimentometric clay fraction is related to the organomineral shell (film) around the soil microparticles. This shell contributes to the linking of microparticles into aggregates at the lower average density. As a result, these aggregates have significantly larger size and lower density and settle with the same velocity as the small particles with the average density of the solid phase during the sedimentation particle-size analysis.

  5. Simple convergent-nozzle aerosol injector for single-particle diffractive imaging with X-ray free-electron lasers.

    PubMed

    Kirian, R A; Awel, S; Eckerskorn, N; Fleckenstein, H; Wiedorn, M; Adriano, L; Bajt, S; Barthelmess, M; Bean, R; Beyerlein, K R; Chavas, L M G; Domaracky, M; Heymann, M; Horke, D A; Knoska, J; Metz, M; Morgan, A; Oberthuer, D; Roth, N; Sato, T; Xavier, P L; Yefanov, O; Rode, A V; Küpper, J; Chapman, H N

    2015-07-01

    A major challenge in high-resolution x-ray free-electron laser-based coherent diffractive imaging is the development of aerosol injectors that can efficiently deliver particles to the peak intensity of the focused X-ray beam. Here, we consider the use of a simple convergent-orifice nozzle for producing tightly focused beams of particles. Through optical imaging we show that 0.5 μm particles can be focused to a full-width at half maximum diameter of 4.2 μm, and we demonstrate the use of such a nozzle for injecting viruses into a micro-focused soft-X-ray FEL beam. PMID:26798816

  6. Beyond crystallography: Diffractive imaging using coherent x-ray light sources

    NASA Astrophysics Data System (ADS)

    Miao, Jianwei; Ishikawa, Tetsuya; Robinson, Ian K.; Murnane, Margaret M.

    2015-05-01

    X-ray crystallography has been central to the development of many fields of science over the past century. It has now matured to a point that as long as good-quality crystals are available, their atomic structure can be routinely determined in three dimensions. However, many samples in physics, chemistry, materials science, nanoscience, geology, and biology are noncrystalline, and thus their three-dimensional structures are not accessible by traditional x-ray crystallography. Overcoming this hurdle has required the development of new coherent imaging methods to harness new coherent x-ray light sources. Here we review the revolutionary advances that are transforming x-ray sources and imaging in the 21st century.

  7. Beyond crystallography: diffractive imaging using coherent x-ray light sources.

    PubMed

    Miao, Jianwei; Ishikawa, Tetsuya; Robinson, Ian K; Murnane, Margaret M

    2015-05-01

    X-ray crystallography has been central to the development of many fields of science over the past century. It has now matured to a point that as long as good-quality crystals are available, their atomic structure can be routinely determined in three dimensions. However, many samples in physics, chemistry, materials science, nanoscience, geology, and biology are noncrystalline, and thus their three-dimensional structures are not accessible by traditional x-ray crystallography. Overcoming this hurdle has required the development of new coherent imaging methods to harness new coherent x-ray light sources. Here we review the revolutionary advances that are transforming x-ray sources and imaging in the 21st century.

  8. Beyond crystallography: Diffractive imaging using coherent x-ray light sources

    SciTech Connect

    Miao, J.; Ishikawa, T.; Robinson, I. K.; Murnane, M. M.

    2015-04-30

    X-ray crystallography has been central to the development of many fields of science over the past century. It has now matured to a point that as long as good-quality crystals are available, their atomic structure can be routinely determined in three dimensions. However, many samples in physics, chemistry, materials science, nanoscience, geology, and biology are noncrystalline, and thus their three-dimensional structures are not accessible by traditional x-ray crystallography. Overcoming this hurdle has required the development of new coherent imaging methods to harness new coherent x-ray light sources. Here we review the revolutionary advances that are transforming x-ray sources and imaging in the 21st century.

  9. DOE-Imaging grant FG02-06ER15829, entitled "Developing Laser-Induced Re-Collision Electron Self-Diffraction" Brief summary of accomplishments

    SciTech Connect

    Igor V. Litvinyuk, and Itzik Ben-Itzhak

    2012-04-01

    experimental chamber. That apparatus was later used for the first demonstration of field-free orientation in CO using two-color laser pulses as well as for a series of other experiments, such as pump-probe studies of molecular dynamics with few-cycle laser pulses, control of electron localization in dissociating hydrogen molecules using two-color laser pulses, and ATI spectra of Xe ionized by two-color laser pulses. In parallel, Dipanwita Ray (Ph.D. student of Lew Cocke) worked on measuring angle-resolved ATI spectra of noble gases using a stereo-ATI phasemeter as a TOF electron spectrometer. She observed the angular diffraction structures in 3D ATI spectra of Ar, Kr and Xe, which were interpreted in terms of the Quantitative Rescattering theory newly developed by C.D. Lin. We also attempted to use a much more powerful OPA (five times more energy per pulse than the one we had at JRML) available at the Advanced Laser Light Source (ALLS) in Montreal to observe LIED. Two visits to ALLS by the PI, Igor Litvinyuk, and one visit by the PI's Ph.D. student (Irina Bocharova) were funded by the grant. Though we failed to observe LIED (the repetition rate of the ALLS OPA was too low at only 100 Hz), this international collaboration resulted in several publications on other related subjects, such as the wavelength dependence of laser Coulomb explosion of hydrogen, the wavelength dependence of non-sequential double ionization of neon and argon, the demonstration of charge-resonance enhanced ionization in CO{sub 2}, and the study of non-elastic scattering processes in H{sub 2}. Theoretical efforts to account for the hydrogen Coulomb explosion experiment resulted in another paper by Maia Magrakvelidze as lead author. Although for various reasons we failed to achieve our main goal of observing LIED, we salute the recent success in this endeavor by Lou DiMauro's group (with theoretical support from our KSU colleague C.D. Lin) published in Nature, which validates our approach.

  10. Laser-driven phosphor-converted white light source for solid-state illumination.

    PubMed

    George, Anthony F; Al-waisawy, Sara; Wright, Jason T; Jadwisienczak, Wojciech M; Rahman, Faiz

    2016-03-10

    Energy efficiency and lighting quality considerations are driving research into laser-pumped white light sources. Laser diodes as pump sources for downconversion phosphors promise freedom from "droop" that adversely affects the efficiency of light-emitting diodes (LEDs). High-intensity laser diode-pumped light sources for applications such as search lights and automobile headlights have been demonstrated recently. Our paper describes the design and construction of a domestic/office-type solid-state luminaire driven by light from an integrated violet laser-diode module. A trichromatic phosphor made from a blend of separate europium-containing rare-earth phosphors was used as the downconversion medium. Mechanical and optical design of the reflector and the phosphor plate are described. Characteristics of both the pump light and the downconverted light are also described. Our studies also looked at the variation of chromaticity coordinates with variation in pump power and the effect of laser speckle on the lamp's light output. Finally, there is a brief discussion of energy conversion efficiency and longevity considerations, comparing pumping with LEDs versus pumping with laser diodes. PMID:26974780

  11. Reporting guide for laser-light shows and displays (21 CFR 1002)

    SciTech Connect

    Not Available

    1988-05-01

    The guide is to be used for reporting laser-light shows or displays incorporating Class IIIb or Class IV lasers only. Separate reports are not required for shows or displays that incorporate Class I, IIa, II, or IIIa laser-projection systems. Such show descriptions must be included in the user instructions and the report for the laser projector. Laser projectors used in any light shows or displays regardless of the class of the projector must be certified by the manufacturer and reported using the guide titled, Guide for Preparing Initial Reports and Model Change Reports on Lasers and Products Containing Lasers, HHS Publication FDA 86-8259. These guides assist manufacturers in providing the information that the Center for Devices and Radiological Health (CDRH) needs to determine how laser-light-shown projections and laser-light shows comply with the Federal standard for laser products (21 CDR 1040.10 and 1040.11) and with the conditions of an approved variance.

  12. [Carbonization in endovasal laser obliteration by radial light guide with wavelength of 1470 and 970 nm].

    PubMed

    Shaidakov, E V; Ilyukhin, E A; Grigoryan, A G; Bulatov, V L; Rosukhovsky, D A; Shonov, O A

    2015-01-01

    The authors assessed the effect of carbonization and its influence on the parameters of endovasal laser obliteration (EVLO) depending on wavelength of laser radiation (970 and 1470 nm) using a light guide with radial emission. They also analysed the value of drop of radiation power of the light guide after performing EVLO and visually assessed the degree of damage of the glass tip of the radial fibre by means of ultra-close-up photography. The study comprised a total of 20 patients with varicose disease. A total of ten procedures of EVLO were performed in two modes: mode one - W-laser 1470 nm, mode two - H-laser 970 nm, using fibre with radial emission, an automatic retractor of the light guide. It was determined that the median of power loss after EVLO with W-laser amounted to 0.6 W, and that for H-laser - 3.15 W (p=0.002). Ultra-close-up photography showed pronounced damage of the glass tip of the radial light guide while using H-laser and no damages while using the W-laser. It was proved that using laser radiation with wavelength of 970 nm using the light guide with radial emission leads to pronounced carbonization on the surface of the glass tip of the light guide, its damage, a decrease in radiation power and risk of mechanical destruction of the flask. Using the laser with wavelength of 1470 nm with the use of radial light guide did not result in the development of such negative effects, which increases the service life of laser fibre and makes it possible to use it for obliteration of several segments in one patient. PMID:26355929

  13. Ultrafast Coherent Diffraction Imaging with X-ray Free-Electron Lasers

    SciTech Connect

    Chapman, H N; Bajt, S; Barty, A; Benner, W; Bogan, M; Frank, M; Hau-Riege, S; London, R; Marchesini, S; Spiller, E; Szoke, A; Woods, B; Boutet, S; Hodgson, K; Hajdu, J; Bergh, M; Burmeister, F; Caleman, C; Huldt, G; Maia, F; Seibert, M M; der Spoel, D v

    2006-08-22

    The ultrafast pulses from X-ray free-electron lasers will enable imaging of non-periodic objects at near-atomic resolution [1, Neutze]. These objects could include single molecules, protein complexes, or virus particles. The specimen would be completely destroyed by the pulse in a Coulomb explosion, but that destruction will only happen after the pulse. The scattering from the sample will give structural information about the undamaged object. There are many technical challenges that must be addressed before carrying out such experiments at an XFEL, which we are doing so with experiments at FLASH, the soft-X-ray FEL at DESY.

  14. Diffractive laser beam homogenizer including a photo-active material and method of fabricating the same

    SciTech Connect

    Bayramian, Andy J; Ebbers, Christopher A; Chen, Diana C

    2014-05-20

    A method of manufacturing a plurality of diffractive optical elements includes providing a partially transmissive slide, providing a first piece of PTR glass, and directing first UV radiation through the partially transmissive slide to impinge on the first piece of PTR glass. The method also includes exposing predetermined portions of the first piece of PTR glass to the first UV radiation and thermally treating the exposed first piece of PTR glass. The method further includes providing a second piece of PTR glass and directing second UV radiation through the thermally treated first piece of PTR glass to impinge on the second piece of PTR glass. The method additionally includes exposing predetermined portions of the second piece of PTR glass to the second UV radiation, thermally treating the exposed second piece of PTR glass, and repeating providing and processing of the second piece of PTR glass using additional pieces of PTR glass.

  15. Rapid prototyping of reflectors for vehicle lighting using laser activated remote phosphor

    NASA Astrophysics Data System (ADS)

    Lachmayer, Roland; Kloppenburg, Gerolf; Wolf, Alexander

    2015-03-01

    Bright white light sources are of significant importance for automotive front lighting systems. Today's upper class vehicles mainly use HID or LED as light source. As a further step in this development laser diode based systems offer high luminance, efficiency and allow the realization of new styling concepts and new dynamic lighting functions. These white laser diode systems can either be realized by mixing different spectral sources or by combining diodes with specific phosphors. Based on the approach of generating light using a laser and remote phosphor, lighting modules are manufactured. Four blue laser diodes (450 nm) are used to activate a phosphor coating and thus to achieve white light. A segmented paraboloid reflector generates the desired light distribution for an additional car headlamp. We use high speed milling and selective laser melting to build the reflector system for this lighting module. We compare the spectral reflection grade of these materials. Furthermore the generated modules are analyzed regarding their efficiency and light distribution. The use of Rapid Prototyping technologies allows an early validation of the chosen concept and is supposed to reduce cost and time in the product development process significantly. Therefor we discuss costs and times of the applied manufacturing technologies.

  16. Beam delivery system with a non-digitized diffractive beam splitter for laser-drilling of silicon

    NASA Astrophysics Data System (ADS)

    Amako, J.; Fujii, E.

    2016-02-01

    We report a beam-delivery system consisting of a non-digitized diffractive beam splitter and a Fourier transform lens. The system is applied to the deep-drilling of silicon using a nanosecond pulse laser in the manufacture of inkjet printer heads. In this process, a circularly polarized pulse beam is divided into an array of uniform beams, which are then delivered precisely to the process points. To meet these requirements, the splitter was designed to be polarization-independent with an efficiency>95%. The optical elements were assembled so as to allow the fine tuning of the effective overall focal length by adjusting the wavefront curvature of the beam. Using the system, a beam alignment accuracy of<5 μm was achieved for a 12-mm-wide beam array and the throughput was substantially improved (10,000 points on a silicon wafer drilled in ~1 min). This beam-delivery scheme works for a variety of laser applications that require parallel processing.

  17. Compact stacking of diode lasers for pulsed light sources of high brightness.

    PubMed

    Alahautala, Taito; Lassila, Erkki; Hernberg, Rolf

    2004-07-20

    A compact stacking architecture for high-power diode-laser arrays is proposed and compared with traditional stacks. The objective of compact stacking is to achieve high brightness values without the use of microlenses. The calculated brightness for a compact stack is over 300 W mm(-2) sr(-1), which is approximately 40 times higher than that of a traditional stack made of similar laser emitters. Even higher brightness values of over 600 W mm(-2) sr(-1) were reached in practice. A laser head was manufactured in which the light from several compact laser stacks could be fiber coupled or the light could be transformed to a highly uniform beam.

  18. Scattered light diagnostics of overdense plasma cavity in solid targets irradiated by an ultraintense laser pulse.

    PubMed

    Andreev, A A; Zhidkov, A G; Uesaka, M; Kinoshita, K; Platonov, K Yu

    2002-09-01

    The light scattered backward from a target illuminated by ultraintense laser pulses carries important information about the nonlinear laser-plasma interaction. We analyze the usefulness of this information by plasma corona analysis with the help of an analytical model we developed, and particle-in-cell simulation. The spectrum of scattered light is shown to be shifted, to be broadened, and to be modulated, in comparison with the initial laser spectrum, and the spectral shift is an indicator of laser pulse contrast ratio.

  19. Beamed neutron emission driven by laser accelerated light ions

    NASA Astrophysics Data System (ADS)

    Kar, S.; Green, A.; Ahmed, H.; Alejo, A.; Robinson, A. P. L.; Cerchez, M.; Clarke, R.; Doria, D.; Dorkings, S.; Fernandez, J.; Mirfayzi, S. R.; McKenna, P.; Naughton, K.; Neely, D.; Norreys, P.; Peth, C.; Powell, H.; Ruiz, J. A.; Swain, J.; Willi, O.; Borghesi, M.

    2016-05-01

    Highly anisotropic, beam-like neutron emission with peak flux of the order of 109 n/sr was obtained from light nuclei reactions in a pitcher-catcher scenario, by employing MeV ions driven by a sub-petawatt laser. The spatial profile of the neutron beam, fully captured for the first time by employing a CR39 nuclear track detector, shows a FWHM divergence angle of ˜ 70^\\circ , with a peak flux nearly an order of magnitude higher than the isotropic component elsewhere. The observed beamed flux of neutrons is highly favourable for a wide range of applications, and indeed for further transport and moderation to thermal energies. A systematic study employing various combinations of pitcher-catcher materials indicates the dominant reactions being d(p, n+p)1H and d(d,n)3He. Albeit insufficient cross-section data are available for modelling, the observed anisotropy in the neutrons’ spatial and spectral profiles is most likely related to the directionality and high energy of the projectile ions.

  20. Comparison between blue lasers and light-emitting diodes for future solid-state lighting: Comparison between blue lasers and light-emitting diodes

    SciTech Connect

    Wierer, Jonathan J.; Tsao, Jeffrey Y.; Sizov, Dmitry S.

    2013-08-01

    Solid-state lighting (SSL) is now the most efficient source of high color quality white light ever created. Nevertheless, the blue InGaN light-emitting diodes (LEDs) that are the light engine of SSL still have significant performance limitations. Foremost among these is the decrease in efficiency at high input current densities widely known as “efficiency droop.” Efficiency droop limits input power densities, contrary to the desire to produce more photons per unit LED chip area and to make SSL more affordable. Pending a solution to efficiency droop, an alternative device could be a blue laser diode (LD). LDs, operated in stimulated emission, can have high efficiencies at much higher input power densities than LEDs can. In this article, LEDs and LDs for future SSL are explored by comparing: their current state-of-the-art input-power-density-dependent power-conversion efficiencies; potential improvements both in their peak power-conversion efficiencies and in the input power densities at which those efficiencies peak; and their economics for practical SSL.