Fabrication of micro/nano optical fiber by mechano-electrospinning

NASA Astrophysics Data System (ADS)

Chen, Qinnan; Wu, Dezhi; Yu, Zhe; Mei, Xuecui; Fang, Ke; Sun, Daoheng

2017-10-01

We study a novel fabrication method of micro/nano optical fiber by mechano-electrospinning (MES) direct-written technology. MES process is able to precisely manipulate the position and diameter of the electro-spun micro/nano fiber by adjusting the mechanical drawing force, which through changing the speed of motion stage (substrate). By adjusting the substrate speed, the nozzle-to-substrate distance and the applied voltage, the poly(methyl methacrylate) (PMMA) micro/nano optical fibers (MNOF) with controlled diameter are obtained and the tapered MNOF are fabricated by continuously changing the substrate speed. The transmission characteristics of PMMA micro/nano fiber is experimentally demonstrated, and a PMMA micro/nano fiber based refractive index sensor is designed. Our works shows the new fabrication method of MNOF by MES has the potential in the field of light mode conversion, optical waveguide coupling, refractive index detection and new micro/nano optical fiber components.

Plasmofluidics: Merging Light and Fluids at the Micro-/Nano-Scale

PubMed Central

Wang, Mingsong; Zhao, Chenglong; Miao, Xiaoyu; Zhao, Yanhui; Rufo, Joseph

2016-01-01

Plasmofluidics is the synergistic integration of plasmonics and micro/nano fluidics in devices and applications in order to enhance performance. There has been significant progress in the emerging field of plasmofluidics in recent years. By utilizing the capability of plasmonics to manipulate light at the nanoscale, combined with the unique optical properties of fluids, and precise manipulation via micro/nano fluidics, plasmofluidic technologies enable innovations in lab-on-a-chip systems, reconfigurable photonic devices, optical sensing, imaging, and spectroscopy. In this review article, we examine and categorize the most recent advances in plasmofluidics into plasmon-enhanced functionalities in microfluidics and microfluidics-enhanced plasmonic devices. The former focuses on plasmonic manipulations of fluids, bubbles, particles, biological cells, and molecules at the micro-/nano-scale. The latter includes technological advances that apply microfluidic principles to enable reconfigurable plasmonic devices and performance-enhanced plasmonic sensors. We conclude with our perspectives on the upcoming challenges, opportunities, and the possible future directions of the emerging field of plasmofluidics. PMID:26140612

Optical and electrical properties of GaN-based light emitting diodes grown on micro- and nano-scale patterned Si substrate

NASA Astrophysics Data System (ADS)

Chiu, Ching-Hsueh; Lin, Chien-Chung; Deng, Dongmei; Kuo, Hao-Chung; Lau, Kei-May

2011-10-01

We investigate the optical and electrical characteristics of the GaN-based light emitting diodes (LEDs) grown on Micro and Nano-scale Patterned silicon substrate (MPLEDs and NPLEDs). The transmission electron microscopy (TEM) images reveal the suppression of threading dislocation density in InGaN/GaN structure on nano-pattern substrate due to nanoscale epitaxial lateral overgrowth (NELOG). The plan-view and cross-section cathodoluminescence (CL) mappings show less defective and more homogeneous active quantum well region growth on nano-porous substrates. From temperature dependent photoluminescence (PL) and low temperature time-resolved photoluminescence (TRPL) measurement, NPLEDs has better carrier confinement and higher radiative recombination rate than MPLEDs. In terms of device performance, NPLEDs exhibits smaller electroluminescence (EL) peak wavelength blue shift, lower reverse leakage current and decreases efficiency droop compared with the MPLEDs. These results suggest the feasibility of using NPSi for the growth of high quality and power LEDs on Si substrates.

Optical Assembly and Characterization System for Nano-Photonics Research

DTIC Science & Technology

2016-03-01

Unlimited Final Report: Optical Assembly and Characterization System for Nano -Photonics Research The views, opinions and/or findings contained in this...reviewed journals: Final Report: Optical Assembly and Characterization System for Nano -Photonics Research Report Title With this equipment funding support...Assembly and Characterization System for Nano -Photonics Research PI: Prof. Weidong Zhou, University of Texas at Arlington (UTA) 500 S. Cooper St

Experimental demonstration of spectrum-sliced elastic optical path network (SLICE).

PubMed

Kozicki, Bartłomiej; Takara, Hidehiko; Tsukishima, Yukio; Yoshimatsu, Toshihide; Yonenaga, Kazushige; Jinno, Masahiko

2010-10-11

We describe experimental demonstration of spectrum-sliced elastic optical path network (SLICE) architecture. We employ optical orthogonal frequency-division multiplexing (OFDM) modulation format and bandwidth-variable optical cross-connects (OXC) to generate, transmit and receive optical paths with bandwidths of up to 1 Tb/s. We experimentally demonstrate elastic optical path setup and spectrally-efficient transmission of multiple channels with bit rates ranging from 40 to 140 Gb/s between six nodes of a mesh network. We show dynamic bandwidth scalability for optical paths with bit rates of 40 to 440 Gb/s. Moreover, we demonstrate multihop transmission of a 1 Tb/s optical path over 400 km of standard single-mode fiber (SMF). Finally, we investigate the filtering properties and the required guard band width for spectrally-efficient allocation of optical paths in SLICE.

Nano-optical functionality based on local photoisomerization in photochromic single crystal

NASA Astrophysics Data System (ADS)

Nakagomi, Ryo; Uchiyama, Kazuharu; Kubota, Satoru; Hatano, Eri; Uchida, Kingo; Naruse, Makoto; Hori, Hirokazu

2018-01-01

Towards the construction of functional devices and systems using optical near-field processes, we demonstrate the multivalent features in the path-branching phenomena in a photochromic single crystal observed in optical phase change between colorless (1o) and blue-colored (1c) phases that transmits in subwavelength scale over a macroscopic spatial range associated with local mechanical distortions induced. To observe the near-field optical processes of transmission path branching, we have developed a top-to-bottom double-probe scanning near-field optical microscope capable of nanometer-scale correlation measurements by two individually position-controlled probes that face each other sandwiching the photochromic material. We have experimentally confirmed that a local near-field optical excitation applied to one side of the photochromic crystal by a probe tip resulted in characteristic structures of subwavelength scale around 100 nm or less that are observed by the other probe tip located on the opposite side. The structures are different from those resulting from far-field excitations that are quantitively evaluated by autocorrelations. The results suggest that the mechanical distortion caused by the local phase change in the photochromic crystal suppresses the phase change of the neighboring molecules. This new type of optical-near-field-induced local photoisomerization has the potential to allow the construction of functional devices with multivalent properties for natural intelligence.

Investigation on the special Smith-Purcell radiation from a nano-scale rectangular metallic grating

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Weiwei; Liu, Weihao, E-mail: liuwhao@ustc.edu.cn; Jia, Qika

The special Smith-Purcell radiation (S-SPR), which is from the radiating eigen modes of a grating, has remarkable higher intensity than the ordinary Smith-Purcell radiation. Yet in previous studies, the gratings were treated as perfect conductor without considering the surface plasmon polaritons (SPPs) which are of significance for the nano-scale gratings especially in the optical region. In present paper, the rigorous theoretical investigations on the S-SPR from a nano-grating with SPPs taken into consideration are carried out. The dispersion relations and radiation characteristics are obtained, and the results are verified by simulations. According to the analyses, the tunable light radiation canmore » be achieved by the S-SPR from a nano-grating, which offers a new prospect for developing the nano-scale light sources.« less

gram-scale metafluids and large area tunable metamaterials: design, fabrication, and nano-optical tomographic characterization (Conference Presentation)

NASA Astrophysics Data System (ADS)

Dionne, Jennifer A.

2016-09-01

Advances in metamaterials and metasurfaces have enabled unprecedented control of light-matter interactions. Metamaterial constituents support high-frequency electric and magnetic dipoles, which can be used as building blocks for new materials capable of negative refraction, electromagnetic cloaking, strong visible-frequency circular dichroism, and enhanced magnetic or chiral transitions in ions and molecules. However, most metamaterials to date have been limited to solid-state, static, narrow-band, and/or small-area structures. Here, we introduce the design, fabrication, and three-dimensional nano-optical characterization of large-area, dynamically-tunable metamaterials and gram-scale metafluids. First, we use transformation optics to design a broadband metamaterial constituent - a metallo-dielectric nanocrescent - characterized by degenerate electric and magnetic dipoles. A periodic array of nanocrescents exhibits large positive and negative refractive indices at optical frequencies, confirmed through simulations of plane wave refraction through a metamaterial prism. Simulations also reveal that the metamaterial optical properties are largely insensitive to the wavelength, orientation and polarization of incident light. Then, we introduce a new tomographic technique, cathodoluminescence (CL) spectroscopic tomography, to probe light-matter interactions in individual nanocrescents with nanometer-scale resolution. Two-dimensional CL maps of the three-dimensional nanostructure are obtained at various orientations, while a filtered back projection is used to reconstruct the CL intensity at each wavelength. The resulting tomograms allow us to locate regions of efficient cathodoluminescence in three dimensions across visible and near-infrared wavelengths, with contributions from material luminescence and radiative decay of electromagnetic eigenmodes. Finally, we demonstrate the fabrication of dynamically tunable large-area metamaterials and gram-scale metafluids, using a

Non-linear non-local molecular electrodynamics with nano-optical fields.

PubMed

Chernyak, Vladimir Y; Saurabh, Prasoon; Mukamel, Shaul

2015-10-28

The interaction of optical fields sculpted on the nano-scale with matter may not be described by the dipole approximation since the fields may vary appreciably across the molecular length scale. Rather than incrementally adding higher multipoles, it is advantageous and more physically transparent to describe the optical process using non-local response functions that intrinsically include all multipoles. We present a semi-classical approach for calculating non-local response functions based on the minimal coupling Hamiltonian. The first, second, and third order response functions are expressed in terms of correlation functions of the charge and the current densities. This approach is based on the gauge invariant current rather than the polarization, and on the vector potential rather than the electric and magnetic fields.

Hybrid reflection type metasurface of nano-antennas designed for optical needle field generation

NASA Astrophysics Data System (ADS)

Wang, Shiyi; Zhan, Qiwen

2015-03-01

We propose a reflection type metal-insulator-metal (MIM) metasurface composed of hybrid optical antennas for comprehensive spatial engineering the properties of optical fields. Its capability is illustrated with an example to create a radially polarized vectorial beam for optical needle field generation. Functioning as local quarter-wave-plates (QWP), the MIM metasurface is designed to convert circularly polarized incident into local linear polarization to create an overall radial polarization with corresponding binary phases and desired normalized amplitude modulation ranged from 0.07 to 1. To obtain enough degrees of freedom, the optical-antenna layer comprises periodic arrangements of double metallic nano-bars with perpendicular placement and single nano-bars respectively for different amplitude modulation requirements. Both of the antennas enable to introduce π/2 retardation while reaching the desired modulation range both for phase and amplitude. Through adjusting the antennas' geometry and array carefully, we shift the gap-surface plasmon resonances facilitated by optical antennas to realize the manipulation of vectorial properties. Designed at 1064 nm wavelength, the particularly generated vectorial light output can be further tightly focused by a high numerical aperture objective to obtain longitudinally polarized flat-top focal field. The so-called optical needle field is a promising candidate for novel applications that transcend disciplinary boundaries. The proposed metasurface establishes a new class of compact optical components based on nano-scale structures, leading to compound functions for vectorial light generation.

Electrochemical method of producing nano-scaled graphene platelets

DOEpatents

Zhamu, Aruna; Jang, Joan; Jang, Bor Z.

2013-09-03

A method of producing nano-scaled graphene platelets with an average thickness smaller than 30 nm from a layered graphite material. The method comprises (a) forming a carboxylic acid-intercalated graphite compound by an electrochemical reaction; (b) exposing the intercalated graphite compound to a thermal shock to produce exfoliated graphite; and (c) subjecting the exfoliated graphite to a mechanical shearing treatment to produce the nano-scaled graphene platelets. Preferred carboxylic acids are formic acid and acetic acid. The exfoliation step in the instant invention does not involve the evolution of undesirable species, such as NO.sub.x and SO.sub.x, which are common by-products of exfoliating conventional sulfuric or nitric acid-intercalated graphite compounds. The nano-scaled platelets are candidate reinforcement fillers for polymer nanocomposites. Nano-scaled graphene platelets are much lower-cost alternatives to carbon nano-tubes or carbon nano-fibers.

Multiple-Path-Length Optical Absorbance Cell

NASA Technical Reports Server (NTRS)

2001-01-01

An optical absorbance cell that offers a selection of multiple optical path lengths has been developed as part of a portable spectrometric instrument that measures absorption spectra of small samples of water and that costs less than does a conventional, non-portable laboratory spectrometer. The instrument is intended, more specifically, for use in studying colored dissolved organic matter (CDOM) in seawater, especially in coastal regions. Accurate characterization of CDOM is necessary for building bio-optical mathematical models of seawater. The multiple path lengths of the absorption cell afford a wide range of sensitivity needed for measuring the optical absorbances associated with the wide range of concentrations of CDOM observed in nature. The instrument operates in the wavelength range of 370 to 725 nm. The major subsystems of the instrument (see figure) include a color-balanced light source; the absorption cell; a peristaltic pump; a high-precision, low-noise fiber optic spectrometer; and a laptop or other personal computer. A fiber-optic cable transmits light from the source to the absorption cell. Other optical fibers transmit light from the absorption cell to the spectrometer,

Optical absorption characteristics in the assessment of powder phosphor-based x-ray detectors: from nano- to micro-scale.

PubMed

Liaparinos, P F

2015-11-21

X-ray phosphor-based detectors have enormously improved the quality of medical imaging examinations through the optimization of optical diffusion. In recent years, with the development of science and technology in the field of materials, improved powder phosphors require structural and optical properties that contribute to better optical signal propagation. The purpose of this paper was to provide a quantitative and qualitative understanding of the optical absorption characteristics in the assessment of powder phosphor-based detectors (from nano- scale up to micro-scale). Variations on the optical absorption parameters (i.e. the light extinction coefficient [Formula: see text] and the percentage probability of light absorption p%) were evaluated based on Mie calculations examining a wide range of light wavelengths, particle refractive indices and sizes. To model and assess the effects of the aforementioned parameters on optical diffusion, Monte Carlo simulation techniques were employed considering: (i) phosphors of different layer thickness, 100 μm (thin layer) and 300 μm (thick layer), respectively, (ii) light extinction coefficient values, 1, 3 and 6 μm(-1), and (iii) percentage probability of light absorption p% in the range 10(-4)-10(-2). Results showed that the [Formula: see text] coefficient is high for phosphor grains in the submicron scale and for low light wavelengths. At higher wavelengths (above 650 nm), optical quanta follow approximately similar depths until interaction for grain diameter 500 nm and 1 μm. Regarding the variability of the refractive index, high variations of the [Formula: see text] coefficient occurred above 1.6. Furthermore, results derived from Monte Carlo modeling showed that high spatial resolution phosphors can be accomplished by increasing the [Formula: see text] parameter. More specifically, the FWHM was found to decrease (i.e. higher resolution): (i) 4.8% at 100 μm and (ii) 9.5%, at 300 μm layer thickness. This study

On the optical path length in refracting media

NASA Astrophysics Data System (ADS)

Hasbun, Javier E.

2018-04-01

The path light follows as it travels through a substance depends on the substance's index of refraction. This path is commonly known as the optical path length (OPL). In geometrical optics, the laws of reflection and refraction are simple examples for understanding the path of light travel from source to detector for constant values of the traveled substances' refraction indices. In more complicated situations, the Euler equation can be quite useful and quite important in optics courses. Here, the well-known Euler differential equation (EDE) is used to obtain the OPL for several index of refraction models. For pedagogical completeness, the OPL is also obtained through a modified Monte Carlo (MC) method, versus which the various results obtained through the EDE are compared. The examples developed should be important in projects involving undergraduate as well as graduate students in an introductory optics course. A simple matlab script (program) is included that can be modified by students who wish to pursue the subject further.

All-optical, thermo-optical path length modulation based on the vanadium-doped fibers.

PubMed

Matjasec, Ziga; Campelj, Stanislav; Donlagic, Denis

2013-05-20

This paper presents an all-fiber, fully-optically controlled, optical-path length modulator based on highly absorbing optical fiber. The modulator utilizes a high-power 980 nm pump diode and a short section of vanadium-co-doped single mode fiber that is heated through absorption and a non-radiative relaxation process. The achievable path length modulation range primarily depends on the pump's power and the convective heat-transfer coefficient of the surrounding gas, while the time response primarily depends on the heated fiber's diameter. An absolute optical length change in excess of 500 µm and a time-constant as short as 11 ms, were demonstrated experimentally. The all-fiber design allows for an electrically-passive and remote operation of the modulator. The presented modulator could find use within various fiber-optics systems that require optical (remote) path length control or modulation.

Method of producing nano-scaled inorganic platelets

DOEpatents

Zhamu, Aruna; Jang, Bor Z.

2012-11-13

The present invention provides a method of exfoliating a layered material (e.g., transition metal dichalcogenide) to produce nano-scaled platelets having a thickness smaller than 100 nm, typically smaller than 10 nm. The method comprises (a) dispersing particles of a non-graphite laminar compound in a liquid medium containing therein a surfactant or dispersing agent to obtain a stable suspension or slurry; and (b) exposing the suspension or slurry to ultrasonic waves at an energy level for a sufficient length of time to produce separated nano-scaled platelets. The nano-scaled platelets are candidate reinforcement fillers for polymer nanocomposites.

Optical Detection and Sizing of Single Nano-Particles Using Continuous Wetting Films

PubMed Central

Hennequin, Yves; McLeod, Euan; Mudanyali, Onur; Migliozzi, Daniel; Ozcan, Aydogan; Dinten, Jean-Marc

2013-01-01

The physical interaction between nano-scale objects and liquid interfaces can create unique optical properties, enhancing the signatures of the objects with sub-wavelength features. Here we show that the evaporation on a wetting substrate of a polymer solution containing sub-micrometer or nano-scale particles creates liquid micro-lenses that arise from the local deformations of the continuous wetting film. These micro-lenses have properties similar to axicon lenses that are known to create beams with a long depth of focus. This enhanced depth of focus allows detection of single nanoparticles using a low magnification microscope objective lens, achieving a relatively wide field-of-view, while also lifting the constraints on precise focusing onto the object plane. Hence, by creating these liquid axicon lenses through spatial deformations of a continuous thin wetting film, we transfer the challenge of imaging individual nano-particles to detecting the light focused by these lenses. As a proof of concept, we demonstrate the detection and sizing of single nano-particles (100 and 200 nm), CpGV granuloviruses as well as Staphylococcus epidermidis bacteria over a wide field of view of e.g., 5.10×3.75 mm2 using a ×5 objective lens with a numerical aperture of 0.15. In addition to conventional lens-based microscopy, this continuous wetting film based approach is also applicable to lensfree computational on-chip imaging, which can be used to detect single nano-particles over a large field-of-view of e.g., >20-30 mm2. These results could be especially useful for high-throughput field-analysis of nano-scale objects using compact and cost-effective microscope designs. PMID:23889001

Optical path switching based differential absorption radiometry for substance detection

NASA Technical Reports Server (NTRS)

Sachse, Glen W. (Inventor)

2005-01-01

An optical path switch divides sample path radiation into a time series of alternating first polarized components and second polarized components. The first polarized components are transmitted along a first optical path and the second polarized components along a second optical path. A first gasless optical filter train filters the first polarized components to isolate at least a first wavelength band thereby generating first filtered radiation. A second gasless optical filter train filters the second polarized components to isolate at least a second wavelength band thereby generating second filtered radiation. A beam combiner combines the first and second filtered radiation to form a combined beam of radiation. A detector is disposed to monitor magnitude of at least a portion of the combined beam alternately at the first wavelength band and the second wavelength band as an indication of the concentration of the substance in the sample path.

Optical path switching based differential absorption radiometry for substance detection

NASA Technical Reports Server (NTRS)

Sachse, Glen W. (Inventor)

2003-01-01

An optical path switch divides sample path radiation into a time series of alternating first polarized components and second polarized components. The first polarized components are transmitted along a first optical path and the second polarized components along a second optical path. A first gasless optical filter train filters the first polarized components to isolate at least a first wavelength band thereby generating first filtered radiation. A second gasless optical filter train filters the second polarized components to isolate at least a second wavelength band thereby generating second filtered radiation. A beam combiner combines the first and second filtered radiation to form a combined beam of radiation. A detector is disposed to monitor magnitude of at least a portion of the combined beam alternately at the first wavelength band and the second wavelength band as an indication of the concentration of the substance in the sample path.

Path to bio-nano-information fusion.

PubMed

Chen, Jia Ming; Ho, Chih-Ming

2006-12-01

This article will discuss the challenges in a new convergent discipline created by the fusion of biotechnology, nanotechnology, and information technology. To illustrate the research challenges, we will begin with an introduction to the nanometer-scale environment in which biology resides, and point out the many important behaviors of matters at that scale. Then we will describe an ideal model system, the cell, for bio-nano-information fusion. Our efforts in advancing this field at the Institute of Cell Mimetic Space Exploration (CMISE) will be introduced here as an example to move toward achieving this goal.

Tunable nano-wrinkling of chiral surfaces: Structure and diffraction optics

NASA Astrophysics Data System (ADS)

Rofouie, P.; Pasini, D.; Rey, A. D.

2015-09-01

Periodic surface nano-wrinkling is found throughout biological liquid crystalline materials, such as collagen films, spider silk gland ducts, exoskeleton of beetles, and flower petals. These surface ultrastructures are responsible for structural colors observed in some beetles and plants that can dynamically respond to external conditions, such as humidity and temperature. In this paper, the formation of the surface undulations is investigated through the interaction of anisotropic interfacial tension, swelling through hydration, and capillarity at free surfaces. Focusing on the cellulosic cholesteric liquid crystal (CCLC) material model, the generalized shape equation for anisotropic interfaces using the Cahn-Hoffman capillarity vector and the Rapini-Papoular anchoring energy are applied to analyze periodic nano-wrinkling in plant-based plywood free surfaces with water-induced cholesteric pitch gradients. Scaling is used to derive the explicit relations between the undulations' amplitude expressed as a function of the anchoring strength and the spatially varying pitch. The optical responses of the periodic nano-structured surfaces are studied through finite difference time domain simulations indicating that CCLC surfaces with spatially varying pitch reflect light in a wavelength higher than that of a CCLC's surface with constant pitch. This structural color change is controlled by the pitch gradient through hydration. All these findings provide a foundation to understand structural color phenomena in nature and for the design of optical sensor devices.

Wafer-scale aluminum nano-plasmonics

NASA Astrophysics Data System (ADS)

George, Matthew C.; Nielson, Stew; Petrova, Rumyana; Frasier, James; Gardner, Eric

2014-09-01

The design, characterization, and optical modeling of aluminum nano-hole arrays are discussed for potential applications in surface plasmon resonance (SPR) sensing, surface-enhanced Raman scattering (SERS), and surface-enhanced fluorescence spectroscopy (SEFS). In addition, recently-commercialized work on narrow-band, cloaked wire grid polarizers composed of nano-stacked metal and dielectric layers patterned over 200 mm diameter wafers for projection display applications is reviewed. The stacked sub-wavelength nanowire grid results in a narrow-band reduction in reflectance by 1-2 orders of magnitude, which can be tuned throughout the visible spectrum for stray light control.

In-line optical fiber metallic mirror reflector for monolithic common path optical coherence tomography probes.

PubMed

Singh, Kanwarpal; Reddy, Rohith; Sharma, Gargi; Verma, Yogesh; Gardecki, Joseph A; Tearney, Guillermo

2018-03-01

Endoscopic optical coherence tomography probes suffer from various artifacts due to dispersion imbalance and polarization mismatch between reference and sample arm light. Such artifacts can be minimized using a common path approach. In this work, we demonstrate a miniaturized common path probe for optical coherence tomography using an inline fiber mirror. A common path optical fiber probe suitable for performing high-resolution endoscopic optical coherence tomography imaging was developed. To achieve common path functionality, an inline fiber mirror was fabricated using a thin gold layer. A commercially available swept source engine was used to test the designed probe in a cadaver human coronary artery ex vivo. We achieved a sensitivity of 104 dB for this probe using a swept source optical coherence tomography system. To test the probe, images of a cadaver human coronary artery were obtained, demonstrating the quality that is comparable to those obtained by OCT systems with separate reference arms. Additionally, we demonstrate recovery of ranging depth by use of a Michelson interferometer in the detection path. We developed a miniaturized monolithic inline fiber mirror-based common path probe for optical coherence tomography. Owing to its simplicity, our design will be helpful in endoscopic applications that require high-resolution probes in a compact form factor while reducing system complexity. Lasers Surg. Med. 50:230-235, 2018. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Ultralight Weight Optical Systems Using Nano-Layered Synthesized Materials

NASA Technical Reports Server (NTRS)

Clark, Natalie; Breckinridge, James

2014-01-01

Optical imaging is important for many NASA science missions. Even though complex optical systems have advanced, the optics, based on conventional glass and mirrors, require components that are thick, heavy and expensive. As the need for higher performance expands, glass and mirrors are fast approaching the point where they will be too large, heavy and costly for spacecraft, especially small satellite systems. NASA Langley Research Center is developing a wide range of novel nano-layered synthesized materials that enable the development and fabrication of ultralight weight optical device systems that enable many NASA missions to collect science data imagery using small satellites. In addition to significantly reducing weight, the nano-layered synthesized materials offer advantages in performance, size, and cost.

Optical Path Switching Based Differential Absorption Radiometry for Substance Detection

NASA Technical Reports Server (NTRS)

Sachse, Glen W. (Inventor)

2000-01-01

A system and method are provided for detecting one or more substances. An optical path switch divides sample path radiation into a time series of alternating first polarized components and second polarized components. The first polarized components are transmitted along a first optical path and the second polarized components along a second optical path. A first gasless optical filter train filters the first polarized components to isolate at least a first wavelength band thereby generating first filtered radiation. A second gasless optical filter train filters the second polarized components to isolate at least a second wavelength band thereby generating second filtered radiation. The first wavelength band and second wavelength band are unique. Further, spectral absorption of a substance of interest is different at the first wavelength band as compared to the second wavelength band. A beam combiner combines the first and second filtered radiation to form a combined beam of radiation. A detector is disposed to monitor magnitude of at least a portion of the combined beam alternately at the first wavelength band and the second wavelength band as an indication of the concentration of the substance in the sample path.

Scaling laws for nanoFET sensors

NASA Astrophysics Data System (ADS)

Zhou, Fu-Shan; Wei, Qi-Huo

2008-01-01

The sensitive conductance change of semiconductor nanowires and carbon nanotubes in response to the binding of charged molecules provides a novel sensing modality which is generally denoted as nanoFET sensors. In this paper, we study the scaling laws of nanoplate FET sensors by simplifying nanoplates as random resistor networks with molecular receptors sitting on lattice sites. Nanowire/tube FETs are included as the limiting cases where the device width goes small. Computer simulations show that the field effect strength exerted by the binding molecules has significant impact on the scaling behaviors. When the field effect strength is small, nanoFETs have little size and shape dependence. In contrast, when the field effect strength becomes stronger, there exists a lower detection threshold for charge accumulation FETs and an upper detection threshold for charge depletion FET sensors. At these thresholds, the nanoFET devices undergo a transition between low and large sensitivities. These thresholds may set the detection limits of nanoFET sensors, while they could be eliminated by designing devices with very short source-drain distance and large width.

Dynamic nano-imaging of label-free living cells using electron beam excitation-assisted optical microscope

PubMed Central

Fukuta, Masahiro; Kanamori, Satoshi; Furukawa, Taichi; Nawa, Yasunori; Inami, Wataru; Lin, Sheng; Kawata, Yoshimasa; Terakawa, Susumu

2015-01-01

Optical microscopes are effective tools for cellular function analysis because biological cells can be observed non-destructively and non-invasively in the living state in either water or atmosphere condition. Label-free optical imaging technique such as phase-contrast microscopy has been analysed many cellular functions, and it is essential technology for bioscience field. However, the diffraction limit of light makes it is difficult to image nano-structures in a label-free living cell, for example the endoplasmic reticulum, the Golgi body and the localization of proteins. Here we demonstrate the dynamic imaging of a label-free cell with high spatial resolution by using an electron beam excitation-assisted optical (EXA) microscope. We observed the dynamic movement of the nucleus and nano-scale granules in living cells with better than 100 nm spatial resolution and a signal-to-noise ratio (SNR) around 10. Our results contribute to the development of cellular function analysis and open up new bioscience applications. PMID:26525841

Dynamic nano-imaging of label-free living cells using electron beam excitation-assisted optical microscope.

PubMed

Fukuta, Masahiro; Kanamori, Satoshi; Furukawa, Taichi; Nawa, Yasunori; Inami, Wataru; Lin, Sheng; Kawata, Yoshimasa; Terakawa, Susumu

2015-11-03

Optical microscopes are effective tools for cellular function analysis because biological cells can be observed non-destructively and non-invasively in the living state in either water or atmosphere condition. Label-free optical imaging technique such as phase-contrast microscopy has been analysed many cellular functions, and it is essential technology for bioscience field. However, the diffraction limit of light makes it is difficult to image nano-structures in a label-free living cell, for example the endoplasmic reticulum, the Golgi body and the localization of proteins. Here we demonstrate the dynamic imaging of a label-free cell with high spatial resolution by using an electron beam excitation-assisted optical (EXA) microscope. We observed the dynamic movement of the nucleus and nano-scale granules in living cells with better than 100 nm spatial resolution and a signal-to-noise ratio (SNR) around 10. Our results contribute to the development of cellular function analysis and open up new bioscience applications.

Dynamic nano-imaging of label-free living cells using electron beam excitation-assisted optical microscope

NASA Astrophysics Data System (ADS)

Fukuta, Masahiro; Kanamori, Satoshi; Furukawa, Taichi; Nawa, Yasunori; Inami, Wataru; Lin, Sheng; Kawata, Yoshimasa; Terakawa, Susumu

2015-11-01

Optical microscopes are effective tools for cellular function analysis because biological cells can be observed non-destructively and non-invasively in the living state in either water or atmosphere condition. Label-free optical imaging technique such as phase-contrast microscopy has been analysed many cellular functions, and it is essential technology for bioscience field. However, the diffraction limit of light makes it is difficult to image nano-structures in a label-free living cell, for example the endoplasmic reticulum, the Golgi body and the localization of proteins. Here we demonstrate the dynamic imaging of a label-free cell with high spatial resolution by using an electron beam excitation-assisted optical (EXA) microscope. We observed the dynamic movement of the nucleus and nano-scale granules in living cells with better than 100 nm spatial resolution and a signal-to-noise ratio (SNR) around 10. Our results contribute to the development of cellular function analysis and open up new bioscience applications.

Tin doped indium oxide anodes with artificially controlled nano-scale roughness using segregated Ag nanoparticles for organic solar cells

NASA Astrophysics Data System (ADS)

Kim, Hyo-Joong; Ko, Eun-Hye; Noh, Yong-Jin; Na, Seok-In; Kim, Han-Ki

2016-09-01

Nano-scale surface roughness in transparent ITO films was artificially formed by sputtering a mixed Ag and ITO layer and wet etching of segregated Ag nanoparticles from the surface of the ITO film. Effective removal of self-segregated Ag particles from the grain boundaries and surface of the crystalline ITO film led to a change in only the nano-scale surface morphology of ITO film without changes in the sheet resistance and optical transmittance. A nano-scale rough surface of the ITO film led to an increase in contact area between the hole transport layer and the ITO anode, and eventually increased the hole extraction efficiency in the organic solar cells (OSCs). The heterojunction OSCs fabricated on the ITO anode with a nano-scale surface roughness exhibited a higher power conversion efficiency of 3.320%, than that (2.938%) of OSCs made with the reference ITO/glass. The results here introduce a new method to improve the performance of OSCs by simply modifying the surface morphology of the ITO anodes.

Scaling Laws for NanoFET Sensors

NASA Astrophysics Data System (ADS)

Wei, Qi-Huo; Zhou, Fu-Shan

2008-03-01

In this paper, we report our numerical studies of the scaling laws for nanoplate field-effect transistor (FET) sensors by simplifying the nanoplates as random resistor networks. Nanowire/tube FETs are included as the limiting cases where the device width goes small. Computer simulations show that the field effect strength exerted by the binding molecules has significant impact on the scaling behaviors. When the field effect strength is small, nanoFETs have little size and shape dependence. In contrast, when the field-effect strength becomes stronger, there exists a lower detection threshold for charge accumulation FETs and an upper detection threshold for charge depletion FET sensors. At these thresholds, the nanoFET devices undergo a transition between low and large sensitivities. These thresholds may set the detection limits of nanoFET sensors. We propose to eliminate these detection thresholds by employing devices with very short source-drain distance and large width.

Quadratic Electro-optic Effect in a Novel Nano-optical Polymer (iodine-doped polyisoprene)

NASA Astrophysics Data System (ADS)

Swamy, Rajendra; Titus, Jitto; Thakur, Mrinal

2004-03-01

In this report, exceptionally large quadratic electro-optic effect in a novel nano-optical polymer will be discussed. The material involved is cis-1,4-polyisoprene or natural rubber which is a nonconjugated conductive polymer[1,2].Upon doping with an acceptor such as iodine, an electron is transferred from its isolated double bond to the dopant leading to a charge-transfer complex. The positive charge (hole) thus created is localized around the double-bond site, within a nanometer dimension - thus, forming a nano-optical material. The quadratic electro-optic measurement on the doped polyisoprene film was made using field-induced birefringence method. The measured Kerr coefficient is about sixty six times that of nitrobenzene at 632 nm. Significant electroabsorption was also observed in this material at 632 nm. 1. M. Thakur, J. Macromol. Sci. - PAC, 2001, A38(12), 1337. 2. M. Thakur, S. Khatavkar and E.J. Parish, J. Macromol. Sci. - PAC, 2003, A40 (12), 1397.

Optical, thermal and morphological study of ZnS doped PVA polymer nano composites

NASA Astrophysics Data System (ADS)

Guruswamy, B.; Ravindrachary, V.; Shruthi, C.; Sagar, Rohan N.; Hegde, Shreedatta

2018-05-01

The effect of ZnS nano particle doping on optical, thermal properties and morphological study of the PVA polymer has been investigated using FTIR, UV-Visible and TGA, FESEM techniques. Nano sized ZnS particles were synthesized by a simple wet chemical route. Pure and ZnS/PVA nano composites were prepared using solution casting technique. The FTIR study confirms that the ZnS nano particles interacts with the OH group of PVA polymer and forms the complex. The formation of these complexes affects the optical and thermal properties of the composite. The changes in optical properties were studied using UV-Vis absorption method. The variation in thermal property was analysed using TGA results. The modified surface morphology analysis was carried out using FESEM.

Architecture and design of optical path networks utilizing waveband virtual links

NASA Astrophysics Data System (ADS)

Ito, Yusaku; Mori, Yojiro; Hasegawa, Hiroshi; Sato, Ken-ichi

2016-02-01

We propose a novel optical network architecture that uses waveband virtual links, each of which can carry several optical paths, to directly bridge distant node pairs. Future photonic networks should not only transparently cover extended areas but also expand fiber capacity. However, the traversal of many ROADM nodes impairs the optical signal due to spectrum narrowing. To suppress the degradation, the bandwidth of guard bands needs to be increased, which degrades fiber frequency utilization. Waveband granular switching allows us to apply broader pass-band filtering at ROADMs and to insert sufficient guard bands between wavebands with minimum frequency utilization offset. The scheme resolves the severe spectrum narrowing effect. Moreover, the guard band between optical channels in a waveband can be minimized, which increases the number of paths that can be accommodated per fiber. In the network, wavelength path granular routing is done without utilizing waveband virtual links, and it still suffers from spectrum narrowing. A novel network design algorithm that can bound the spectrum narrowing effect by limiting the number of hops (traversed nodes that need wavelength path level routing) is proposed in this paper. This algorithm dynamically changes the waveband virtual link configuration according to the traffic distribution variation, where optical paths that need many node hops are effectively carried by virtual links. Numerical experiments demonstrate that the number of necessary fibers is reduced by 23% compared with conventional optical path networks.

Investigation of the Structural, Electrical, and Optical Properties of the Nano-Scale GZO Thin Films on Glass and Flexible Polyimide Substrates

PubMed Central

Wang, Fang-Hsing; Chen, Kun-Neng; Hsu, Chao-Ming; Liu, Min-Chu; Yang, Cheng-Fu

2016-01-01

In this study, Ga2O3-doped ZnO (GZO) thin films were deposited on glass and flexible polyimide (PI) substrates at room temperature (300 K), 373 K, and 473 K by the radio frequency (RF) magnetron sputtering method. After finding the deposition rate, all the GZO thin films with a nano-scale thickness of about 150 ± 10 nm were controlled by the deposition time. X-ray diffraction patterns indicated that the GZO thin films were not amorphous and all exhibited the (002) peak, and field emission scanning electron microscopy showed that only nano-scale particles were observed. The dependences of the structural, electrical, and optical properties of the GZO thin films on different deposition temperatures and substrates were investigated. X-ray photoemission spectroscopy (XPS) was used to measure the elemental composition at the chemical and electronic states of the GZO thin films deposited on different substrates, which could be used to clarify the mechanism of difference in electrical properties of the GZO thin films. In this study, the XPS binding energy spectra of Ga2p3/2 and Ga2p1/2 peaks, Zn2p3/2 and Zn2p1/2 peaks, the Ga3d peak, and O1s peaks for GZO thin films on glass and PI substrates were well compared. PMID:28335216

Nano-optical information storage induced by the nonlinear saturable absorption effect

NASA Astrophysics Data System (ADS)

Wei, Jingsong; Liu, Shuang; Geng, Yongyou; Wang, Yang; Li, Xiaoyi; Wu, Yiqun; Dun, Aihuan

2011-08-01

Nano-optical information storage is very important in meeting information technology requirements. However, obtaining nanometric optical information recording marks by the traditional optical method is difficult due to diffraction limit restrictions. In the current work, the nonlinear saturable absorption effect is used to generate a subwavelength optical spot and to induce nano-optical information recording and readout. Experimental results indicate that information marks below 100 nm are successfully recorded and read out by a high-density digital versatile disk dynamic testing system with a laser wavelength of 405 nm and a numerical aperture of 0.65. The minimum marks of 60 nm are realized, which is only about 1/12 of the diffraction-limited theoretical focusing spot. This physical scheme is very useful in promoting the development of optical information storage in the nanoscale field.

Method of producing exfoliated graphite, flexible graphite, and nano-scaled graphene platelets

DOEpatents

Zhamu, Aruna; Shi, Jinjun; Guo, Jiusheng; Jang, Bor Z.

2010-11-02

The present invention provides a method of exfoliating a layered material (e.g., graphite and graphite oxide) to produce nano-scaled platelets having a thickness smaller than 100 nm, typically smaller than 10 nm. The method comprises (a) dispersing particles of graphite, graphite oxide, or a non-graphite laminar compound in a liquid medium containing therein a surfactant or dispersing agent to obtain a stable suspension or slurry; and (b) exposing the suspension or slurry to ultrasonic waves at an energy level for a sufficient length of time to produce separated nano-scaled platelets. The nano-scaled platelets are candidate reinforcement fillers for polymer nanocomposites. Nano-scaled graphene platelets are much lower-cost alternatives to carbon nano-tubes or carbon nano-fibers.

Optical gain in type–II InGaAs/GaAsSb quantum well nano-heterostructure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nirmal, H. K.; Yadav, Nisha; Lal, Pyare

2015-08-28

In this paper, we have simulated optical gain in type-II InGaAs/GaAsSb quantum well based nano-scale heterostructure. In order to simulate the optical gain, the heterostructure has been modeled with the help of six band k.p method. The 6 × 6 diagonalized k.p Hamiltonian has been solved to evaluate the valence sub-bands (i.e. light and heavy hole energies); and then optical matrix elements and optical gain within TE (Transverse Electric) mode has been calculated. The results obtained suggest that peak optical gain in the heterostructure can be achieved at the lasing wavelength ~ 1.95 µm (SWIR region) and at corresponding energy ~more » 0.635 eV.« less

Nano-optical conveyor belt, part I: Theory.

PubMed

Hansen, Paul; Zheng, Yuxin; Ryan, Jason; Hesselink, Lambertus

2014-06-11

We propose a method for peristaltic transport of nanoparticles using the optical force field over a nanostructured surface. Nanostructures may be designed to produce strong near-field hot spots when illuminated. The hot spots function as optical traps, separately addressable by their resonant wavelengths and polarizations. By activating closely packed traps sequentially, nanoparticles may be handed off between adjacent traps in a peristaltic fashion. A linear repeating structure of three separately addressable traps forms a "nano-optical conveyor belt"; a unit cell with four separately addressable traps permits controlled peristaltic transport in the plane. Using specifically designed activation sequences allows particle sorting.

Demonstration of an ultra-wideband optical fiber inline polarizer with metal nano-grid on the fiber tip.

PubMed

Lin, Yongbin; Guo, Junpeng; Lindquist, Robert G

2009-09-28

Dramatic increase in the bandwidth of optical fiber inline polarizer can be achieved by using metal nano-grid on the fiber tip. However, high extinction ratio of such fiber polarizer requires high spatial frequency metal nano girds with high aspect ratio on the small area of optical fiber tip. We report the development of a nano-fabrication process on the optical fiber tip, and the design and realization of the first ultra-wideband fiber inline polarization device with Au nano gird fabricated on a single mode optical fiber end face.

Study of linear optical parameters of sodium sulphide nano-particles added ADP crystals

NASA Astrophysics Data System (ADS)

Kochuparampil, A. P.; Joshi, J. H.; Dixit, K. P.; Jethva, H. O.; Joshi, M. J.

2017-05-01

Ammonium Dihydrogen Phosphate (ADP) is one of the nonlinear optical crystals. It is having various applications like optical mixing, electro-optical modulator, harmonic generators, etc. Chalcogenide compounds are poorly soluble in water and difficult to add in the water soluble ADP crystals. The solubility of Chalcogenide compounds can be increased by synthesizing the nano-structured samples with suitable capping agent. In the present study sodium sulphide was added in to ADP to modify its linear optical parameters. Sodium sulphide nano particles were synthesized by co-precipitation technique using Ethylene diamine as capping agent followed by microwave irradiation. The powder XRD confirmed the nano-structured nature of sodium sulphide nano particles. The solubility of nanoparticles of sodium sulphide increased significantly in water compared to the bulk. Pure and Na2S added ADP crystals were grown by slow solvent evaporation method at room temperature. The presence of sodium in ADP was confirmed by AAS. The UV-Vis spectra were recorded for all crystals. Various optical parameters like, transmittance, energy band gap, extinction coefficient, refractive index, optical conductivity, etc. were evaluated. The electronic polarizibility of pure and doped crystals calculated from energy band gap. The effect of doping concentration was found on various parameters.

Research on the Calculation Method of Optical Path Difference of the Shanghai Tian Ma Telescope

NASA Astrophysics Data System (ADS)

Dong, J.; Fu, L.; Jiang, Y. B.; Liu, Q. H.; Gou, W.; Yan, F.

2016-03-01

Based on the Shanghai Tian Ma Telescope (TM), an optical path difference calculation method of the shaped Cassegrain antenna is presented in the paper. Firstly, the mathematical model of the TM optics is established based on the antenna reciprocity theorem. Secondly, the TM sub-reflector and main reflector are fitted by the Non-Uniform Rational B-Splines (NURBS). Finally, the method of optical path difference calculation is implemented, and the expanding application of the Ruze optical path difference formulas in the TM is researched. The method can be used to calculate the optical path difference distributions across the aperture field of the TM due to misalignment like the axial and lateral displacements of the feed and sub-reflector, or the tilt of the sub-reflector. When the misalignment quantity is small, the expanding Ruze optical path difference formulas can be used to calculate the optical path difference quickly. The paper supports the real-time measurement and adjustment of the TM structure. The research has universality, and can provide reference for the optical path difference calculation of other radio telescopes with shaped surfaces.

Integration of micro-/nano-/quantum-scale photonic devices: scientific and technological considerations

NASA Astrophysics Data System (ADS)

Lee, El-Hang; Lee, Seung-Gol; O, Beom Hoan; Park, Se Geun

2004-08-01

Scientific and technological issues and considerations regarding the integration of miniaturized microphotonic devices, circuits and systems in micron, submicron, and quantum scale, are presented. First, we examine the issues regarding the miniaturization of photonic devices including the size effect, proximity effect, energy confinement effect, microcavity effect, optical and quantum interference effect, high field effect, nonlinear effect, noise effect, quantum optical effect, and chaotic effect. Secondly, we examine the issues regarding the interconnection including the optical alignment, minimizing the interconnection losses, and maintaining optical modes. Thirdly, we address the issues regarding the two-dimensional or three-dimensional integration either in a hybrid format or in a monolithic format between active devices and passive devices of varying functions. We find that the concept of optical printed circuit board (O-PCB) that we propose is highly attractive as a platform for micro/nano/quantum-scale photonic integration. We examine the technological issues to be addressed in the process of fabrication, characterization, and packaging for actual implementation of the miniaturization, interconnection and integration. Devices that we have used for our study include: mode conversion schemes, micro-ring and micro-racetrack resonator devices, multimode interference devices, lasers, vertical cavity surface emitting microlasers, and their arrays. Future prospects are also discussed.

Nano-scale optical circuits and self-organized lightwave network (SOLNET) fabricated using sol-gel materials with photo-induced refractive index increase

NASA Astrophysics Data System (ADS)

Ono, Shigeru; Yoshimura, Tetsuzo; Sato, Tetsuo; Oshima, Juro

2009-02-01

Recently, Nissan Chemical Industries, LTD, developed the photo-induced refractive index variation sol-gel materials, in which the refractive index increases from 1.65 to 1.85 by ultra-violet (UV) light exposure and baking. The materials enable us to fabricate high-index-contract waveguides without developing/etching processes and strong-lightconfinement self-organized lightwave network (SOLNET). Therefore, the materials are expected promising for nanoscale optical circuits with self-alignment capability. Nano-scale optical circuits with core thickness of ~230 nm and core width of ~1 μm were fabricated. Propagation loss was 1.86 dB/cm for TE mode and 1.89 dB/cm for TM mode at 633 nm in wavelength, indicating that there were small polarization dependences. Spot sizes of guided beams along core width direction and along core thickness direction were respectively 0.6 μm and 0.3 μm for both TE and TM mode. Bending loss of S-bending waveguides was reduced from 0.44 dB to 0.24 dB for TE mode with increasing the bending curvature radius from 5 μm to 60 μm. Difference in bending loss between TM and TE mode was less than 10%. Branching loss of Y-branching waveguides was reduced from 1.33 dB to 0.08 dB for TE mode, and from 1.34 dB to 0.12 dB for TM mode with decreasing the branching angle from 80° to 20°. These results indicate that the photoinduced refractive index variation sol-gel materials can realize miniaturized optical circuits with sizes of several tens μm and guided beam confinement within a cross-section area less than 1.0 μm2 with small polarization dependences, suggesting potential applications to intra-chip optical interconnects. In addtion, we fabricated self-organized lightwave network (SOLNET) using the photo-induced refractive index variation sol-gel materials. When write beams of 405 nm in wavelength were introduced into the sol-gel thin film under baking at 200°C, self-focusing was induced, and SOLNET was formed. SOLNET fabricated by low write

Optical nano-biosensing interface via nucleic acid amplification strategy: construction and application.

PubMed

Zhou, Hong; Liu, Jing; Xu, Jing-Juan; Zhang, Shu-Sheng; Chen, Hong-Yuan

2018-03-21

Modern optical detection technology plays a critical role in current clinical detection due to its high sensitivity and accuracy. However, higher requirements such as extremely high detection sensitivity have been put forward due to the clinical needs for the early finding and diagnosing of malignant tumors which are significant for tumor therapy. The technology of isothermal amplification with nucleic acids opens up avenues for meeting this requirement. Recent reports have shown that a nucleic acid amplification-assisted modern optical sensing interface has achieved satisfactory sensitivity and accuracy, high speed and specificity. Compared with isothermal amplification technology designed to work completely in a solution system, solid biosensing interfaces demonstrated better performances in stability and sensitivity due to their ease of separation from the reaction mixture and the better signal transduction on these optical nano-biosensing interfaces. Also the flexibility and designability during the construction of these nano-biosensing interfaces provided a promising research topic for the ultrasensitive detection of cancer diseases. In this review, we describe the construction of the burgeoning number of optical nano-biosensing interfaces assisted by a nucleic acid amplification strategy, and provide insightful views on: (1) approaches to the smart fabrication of an optical nano-biosensing interface, (2) biosensing mechanisms via the nucleic acid amplification method, (3) the newest strategies and future perspectives.

All-Optical Wavelength-Path Service With Quality Assurance by Multilayer Integration System

NASA Astrophysics Data System (ADS)

Yagi, Mikio; Tanaka, Shinya; Satomi, Shuichi; Ryu, Shiro; Asano, Shoichiro

2006-09-01

In the future all-optical network controlled by generalized multiprotocol label switching (GMPLS), the wavelength path between end nodes will change dynamically. This inevitably means that the fiber parameters along the wavelength path will also vary. This variation in fiber parameters influences the signal quality of high-speed-transmission system (bit rates over 40 Gb/s). Therefore, at a path setup, the fiber-parameter effect should be adequately compensated. Moreover, the path setup must be completed fast enough to meet the network-application demands. To realize the rapid setup of adequate paths, a multilayer integration system for all-optical wavelength-path quality assurance is proposed. This multilayer integration system is evaluated in a field trial. In the trial, the GMPLS control plane, measurement plane, and data plane coordinated to maintain the quality of a 40-Gb/s wavelength path that would otherwise be degraded by the influence of chromatic dispersion. It is also demonstrated that the multilayer integration system can assure the signal quality in the face of not only chromatic dispersion but also degradation in the optical signal-to-noise ratio by the use of a 2R regeneration system. Our experiments confirm that the proposed multilayer integration system is an essential part of future all-optical networks.

Rainbow peacock spiders inspire miniature super-iridescent optics.

PubMed

Hsiung, Bor-Kai; Siddique, Radwanul Hasan; Stavenga, Doekele G; Otto, Jürgen C; Allen, Michael C; Liu, Ying; Lu, Yong-Feng; Deheyn, Dimitri D; Shawkey, Matthew D; Blackledge, Todd A

2017-12-22

Colour produced by wavelength-dependent light scattering is a key component of visual communication in nature and acts particularly strongly in visual signalling by structurally-coloured animals during courtship. Two miniature peacock spiders (Maratus robinsoni and M. chrysomelas) court females using tiny structured scales (~ 40 × 10 μm 2 ) that reflect the full visual spectrum. Using TEM and optical modelling, we show that the spiders' scales have 2D nanogratings on microscale 3D convex surfaces with at least twice the resolving power of a conventional 2D diffraction grating of the same period. Whereas the long optical path lengths required for light-dispersive components to resolve individual wavelengths constrain current spectrometers to bulky sizes, our nano-3D printed prototypes demonstrate that the design principle of the peacock spiders' scales could inspire novel, miniature light-dispersive components.

Nano-scale imaging and spectroscopy of plasmonic systems, thermal near-fields, and phase separation in complex oxides

NASA Astrophysics Data System (ADS)

Jones, Andrew C.

Optical spectroscopy represents a powerful characterization technique with the ability to directly interact with the electronic, spin, and lattice excitations in matter. In addition, through implementation of ultrafast techniques, further insight into the real-time dynamics of elementary interactions can be gained. However, the resolution of far-field microscopy techniques is restricted by the diffraction limit setting a spatial resolution limit in the 100s nm to micron range for visible and IR light, respectively. This resolution is too coarse for the characterization of mesoscopic phenomena in condensed matter physics. The development of experimental techniques with nanoscale resolution and sensitivity to optical fields has been a long standing obstacle to the characterization of condensed matter systems on their natural length scales. This dissertation focuses on the fundamental near-field optical properties of surfaces and nanoscale systems as well as the utilization of nano-optical techniques, specifically apertureless scattering-type Scanning Near-field Optical Microscopy (s-SNOM), to characterize said optical properties with nanometer scale resolution. First, the s-SNOM characterization of the field enhancement associated with the localized surface plasmon resonances on metallic structures is discussed. With their ability to localize light, plasmonic nano-structures are promising candidate systems to serve as molecular sensors and nano-photonic devices; however, it is well known that particle morphology and the plasmon resonance alone do not uniquely reflect the details of the local field distribution. Here, I demonstrate the use interferometric s-SNOM for imaging of the near-fields associated with plasmonic resonances of crystalline triangular silver nano-prisms in the visible spectral range. I subsequently show the extension of the concept of a localized plasmon into the mid-IR spectral range with the characterization of near-fields of silver nano

"Nano" Scale Biosignatures and the Search for Extraterrestrial Life

NASA Technical Reports Server (NTRS)

Oehler, D. Z.; Robert, F.; Meibom, A.; Mostefaoui, S.; Selo, M.; Walter, M. R.; Sugitani, K.; Allwood, A.; Mimura, K.; Gibson, E. K.

2008-01-01

A critical step in the search for remnants of potential life forms on other planets lies in our ability to recognize indigenous fragments of ancient microbes preserved in some of Earth's oldest rocks. To this end, we are building a database of nano-scale chemical and morphological characteristics of some of Earth's oldest organic microfossils. We are primarily using the new technology of Nano-Secondary ion mass spectrometry (NanoSIMS) which provides in-situ, nano-scale elemental analysis of trace quantities of organic residues. The initial step was to characterize element composition of well-preserved, organic microfossils from the late Proterozoic (0.8 Ga) Bitter Springs Formation of Australia. Results from that work provide morphologic detail and nitrogen/carbon ratios that appear to reflect the well-established biological origin of these 0.8 Ga fossils.

Horizontal Line-of-Sight Turbulence Over Near-Ground Paths and Implications for Adaptive Optics Corrections in Laser Communications.

PubMed

Levine, B M; Martinsen, E A; Wirth, A; Jankevics, A; Toledo-Quinones, M; Landers, F; Bruno, T L

1998-07-20

Atmospheric turbulence over long horizontal paths perturbs phase and can also cause severe intensity scintillation in the pupil of an optical communications receiver, which limits the data rate over which intensity-based modulation schemes can operate. The feasibility of using low-order adaptive optics by applying phase-only corrections over horizontal propagation paths is investigated. A Shack-Hartmann wave-front sensor was built and data were gathered on paths 1 m above ground and between a 1- and 2.5-km range. Both intensity fluctuations and optical path fluctuation statistics were gathered within a single frame, and the wave-front reconstructor was modified to allow for scintillated data. The temporal power spectral density for various Zernike polynomial modes was used to determine the effects of the expected corrections by adaptive optics. The slopes of the inertial subrange of turbulence were found to be less than predicted by Kolmogorov theory with an infinite outer scale, and the distribution of variance explained by increasing order was also found to be different. Statistical analysis of these data in the 1-km range indicates that at communications wavelengths of 1.3 mum, a significant improvement in transmitted beam quality could be expected most of the time, to a performance of 10% Strehl ratio or better.

Ultrahigh responsivity of optically active, semiconducting asymmetric nano-channel diodes

NASA Astrophysics Data System (ADS)

Akbas, Y.; Stern, A.; Zhang, L. Q.; Alimi, Y.; Song, A. M.; Iñiguez-de-la-Torre, I.; Mateos, J.; González, T.; Wicks, G. W.; Sobolewski, Roman

2015-10-01

We present our research on the fabrication and optical characterization of novel semiconducting asymmetric nano-channel diodes (ANCDs). We focus on optical properties of ANCDs and demonstrate that they can be operated as very sensitive, single-photon-level, visible-light photodetectors. Our test devices consisted of 1.2-μm-long, ∼200- to 300-nm-wide channels that were etched in an InGaAs/InAlAs quantum-well hetero structure with a twodimensional electron gas layer. The ANCD I-V curves were collected by measuring the transport current both in the dark and under 800-nm-wavelength, continuous-wave-light laser illumination. In all of our devices, the impact of the light illumination was very clear, and there was a substantial photocurrent, even for incident optical power as low as 1 nW. The magnitude of the optical responsivity in ANCDs with the conducting nano-channel increased linearly with a decrease in optical power over many orders of magnitude, reaching a value of almost 10,000 A/W at 1-nW excitation.

In-situ and path-averaged measurements of aerosol optical properties

NASA Astrophysics Data System (ADS)

van Binsbergen, Sven A.; Grossmann, Peter; February, Faith J.; Cohen, Leo H.; van Eijk, Alexander M. J.; Stein, Karin U.

2017-09-01

This paper compares in-situ and path-averaged measurements of the electro-optical transmission, with emphasis on aerosol effects. The in-situ sensors consisted of optical particle counters (OPC), the path-averaged data was provided by a 7-wavelength transmissometer (MSRT) and scintillometers (BLS). Data were collected at two sites: a homogeneous test site in Northern Germany, and over the inhomogeneous False Bay near Cape Town, South Africa. A retrieval algorithm was developed to infer characteristics of the aerosol size distribution (Junge approximation) from the MSRT data. A comparison of the various sensors suggests that the optical particle counters are over optimistic in their estimate of the transmission. For the homogeneous test site, in-situ and path-averaged sensors yield similar results. For the inhomogeneous test site, sensors may react differently or temporally separated to meteorological events such as a change in wind speed and/or direction.

Advances in nano-scaled biosensors for biomedical applications.

PubMed

Wang, Jianling; Chen, Guihua; Jiang, Hui; Li, Zhiyong; Wang, Xuemei

2013-08-21

Recently, a growing amount of attention has been focused on the utility of biosensors for biomedical applications. Combined with nanomaterials and nanostructures, nano-scaled biosensors are installed for biomedical applications, such as pathogenic bacteria monitoring, virus recognition, disease biomarker detection, among others. These nano-biosensors offer a number of advantages and in many respects are ideally suited to biomedical applications, which could be made as extremely flexible devices, allowing biomedical analysis with speediness, excellent selectivity and high sensitivity. This minireview discusses the literature published in the latest years on the advances in biomedical applications of nano-scaled biosensors for disease bio-marking and detection, especially in bio-imaging and the diagnosis of pathological cells and viruses, monitoring pathogenic bacteria, thus providing insight into the future prospects of biosensors in relevant clinical applications.

CFO compensation method using optical feedback path for coherent optical OFDM system

NASA Astrophysics Data System (ADS)

Moon, Sang-Rok; Hwang, In-Ki; Kang, Hun-Sik; Chang, Sun Hyok; Lee, Seung-Woo; Lee, Joon Ki

2017-07-01

We investigate feasibility of carrier frequency offset (CFO) compensation method using optical feedback path for coherent optical orthogonal frequency division multiplexing (CO-OFDM) system. Recently proposed CFO compensation algorithms provide wide CFO estimation range in electrical domain. However, their practical compensation range is limited by sampling rate of an analog-to-digital converter (ADC). This limitation has not drawn attention, since the ADC sampling rate was high enough comparing to the data bandwidth and CFO in the wireless OFDM system. For CO-OFDM, the limitation is becoming visible because of increased data bandwidth, laser instability (i.e. large CFO) and insufficient ADC sampling rate owing to high cost. To solve the problem and extend practical CFO compensation range, we propose a CFO compensation method having optical feedback path. By adding simple wavelength control for local oscillator, the practical CFO compensation range can be extended to the sampling frequency range. The feasibility of the proposed method is experimentally investigated.

MD Simulation on Collision Behavior Between Nano-Scale TiO₂ Particles During Vacuum Cold Spraying.

PubMed

Yao, Hai-Long; Yang, Guan-Jun; Li, Chang-Jiu

2018-04-01

Particle collision behavior influences significantly inter-nano particle bonding formation during the nano-ceramic coating deposition by vacuum cold spraying (or aerosol deposition method). In order to illuminate the collision behavior between nano-scale ceramic particles, molecular dynamic simulation was applied to explore impact process between nano-scale TiO2 particles through controlling impact velocities. Results show that the recoil efficiency of the nano-scale TiO2 particle is decreased with the increase of the impact velocity. Nano-scale TiO2 particle exhibits localized plastic deformation during collision at low velocities, while it is intensively deformed by collision at high velocities. This intensive deformation promotes the nano-particle adhesion rather than rebounding off. A relationship between the adhesion energy and the rebound energy is established for the bonding formation of the nano-scale TiO2 particle. The adhesion energy required to the bonding formation between nano-scale ceramic particles can be produced by high velocity collision.

New Remote Gas Sensor Using Rapid Electro-Optical Path Switching

NASA Technical Reports Server (NTRS)

Sachse, G. W.; Lebel, P. J.; Wallio, H. A.; Vay, S. A.; Wang, L. G.

1994-01-01

Innovative gas filter correlation radiometer (GFCR) features nonmechanical switching of internal optical paths. Incoming radiation switched electro-optically, by means of polarization, between two optical paths, one of which contains correlation gas cell while other does not. Advantages include switching speed, 2 to 3 orders of magnitude faster than mechanical techniques, and high reliability. Applications include regional studies of atmospheric chemistry from either manned or unmanned aircraft as well as satellite studies of global distributions, sources and sink mechanisms for key species involved in chemistry of troposphere. Commercial applications: ability to survey many miles of natural gas pipelines rapidly from aircraft, pinpointing gas leaks by measuring methane at 2.3 micrometers.

Method of producing carbon coated nano- and micron-scale particles

DOEpatents

Perry, W. Lee; Weigle, John C; Phillips, Jonathan

2013-12-17

A method of making carbon-coated nano- or micron-scale particles comprising entraining particles in an aerosol gas, providing a carbon-containing gas, providing a plasma gas, mixing the aerosol gas, the carbon-containing gas, and the plasma gas proximate a torch, bombarding the mixed gases with microwaves, and collecting resulting carbon-coated nano- or micron-scale particles.

Fabrication and Operation of a Nano-Optical Conveyor Belt

PubMed Central

Ryan, Jason; Zheng, Yuxin; Hansen, Paul; Hesselink, Lambertus

2015-01-01

The technique of using focused laser beams to trap and exert forces on small particles has enabled many pivotal discoveries in the nanoscale biological and physical sciences over the past few decades. The progress made in this field invites further study of even smaller systems and at a larger scale, with tools that could be distributed more easily and made more widely available. Unfortunately, the fundamental laws of diffraction limit the minimum size of the focal spot of a laser beam, which makes particles smaller than a half-wavelength in diameter hard to trap and generally prevents an operator from discriminating between particles which are closer together than one half-wavelength. This precludes the optical manipulation of many closely-spaced nanoparticles and limits the resolution of optical-mechanical systems. Furthermore, manipulation using focused beams requires beam-forming or steering optics, which can be very bulky and expensive. To address these limitations in the system scalability of conventional optical trapping our lab has devised an alternative technique which utilizes near-field optics to move particles across a chip. Instead of focusing laser beams in the far-field, the optical near field of plasmonic resonators produces the necessary local optical intensity enhancement to overcome the restrictions of diffraction and manipulate particles at higher resolution. Closely-spaced resonators produce strong optical traps which can be addressed to mediate the hand-off of particles from one to the next in a conveyor-belt-like fashion. Here, we describe how to design and produce a conveyor belt using a gold surface patterned with plasmonic C-shaped resonators and how to operate it with polarized laser light to achieve super-resolution nanoparticle manipulation and transport. The nano-optical conveyor belt chip can be produced using lithography techniques and easily packaged and distributed. PMID:26381708

Fabrication and Operation of a Nano-Optical Conveyor Belt.

PubMed

Ryan, Jason; Zheng, Yuxin; Hansen, Paul; Hesselink, Lambertus

2015-08-26

The technique of using focused laser beams to trap and exert forces on small particles has enabled many pivotal discoveries in the nanoscale biological and physical sciences over the past few decades. The progress made in this field invites further study of even smaller systems and at a larger scale, with tools that could be distributed more easily and made more widely available. Unfortunately, the fundamental laws of diffraction limit the minimum size of the focal spot of a laser beam, which makes particles smaller than a half-wavelength in diameter hard to trap and generally prevents an operator from discriminating between particles which are closer together than one half-wavelength. This precludes the optical manipulation of many closely-spaced nanoparticles and limits the resolution of optical-mechanical systems. Furthermore, manipulation using focused beams requires beam-forming or steering optics, which can be very bulky and expensive. To address these limitations in the system scalability of conventional optical trapping our lab has devised an alternative technique which utilizes near-field optics to move particles across a chip. Instead of focusing laser beams in the far-field, the optical near field of plasmonic resonators produces the necessary local optical intensity enhancement to overcome the restrictions of diffraction and manipulate particles at higher resolution. Closely-spaced resonators produce strong optical traps which can be addressed to mediate the hand-off of particles from one to the next in a conveyor-belt-like fashion. Here, we describe how to design and produce a conveyor belt using a gold surface patterned with plasmonic C-shaped resonators and how to operate it with polarized laser light to achieve super-resolution nanoparticle manipulation and transport. The nano-optical conveyor belt chip can be produced using lithography techniques and easily packaged and distributed.

Photonic-crystal membranes for optical detection of single nano-particles, designed for biosensor application.

PubMed

Grepstad, Jon Olav; Kaspar, Peter; Solgaard, Olav; Johansen, Ib-Rune; Sudbø, Aasmund S

2012-03-26

A sensor designed to detect bio-molecules is presented. The sensor exploits a planar 2D photonic crystal (PC) membrane with sub-micron thickness and through holes, to induce high optical fields that allow detection of nano-particles smaller than the diffraction limit of an optical microscope. We report on our design and fabrication of a PC membrane with a nano-particle trapped inside. We have also designed and built an imaging system where an optical microscope and a CCD camera are used to take images of the PC membrane. Results show how the trapped nano-particle appears as a bright spot in the image. In a first experimental realization of the imaging system, single particles with a radius of 75 nm can be detected.

Mechanical and optical characterization of tungsten oxynitride (W-O-N) nano-coatings

NASA Astrophysics Data System (ADS)

Nunez, Oscar Roberto

Aation and cation doping of transition metal oxides has recently gained attention as a viable option to design materials for application in solar energy conversion, photo-catalysis, transparent electrodes, photo-electrochemical cells, electrochromics and flat panel displays in optoelectronics. Specifically, nitrogen doped tungsten oxide (WO3) has gained much attention for its ability to facilitate optical property tuning while also demonstrating enhanced photo-catalytic and photochemical properties. The effect of nitrogen chemistry and mechanics on the optical and mechanical properties of tungsten oxynitride (W-O-N) nano-coatings is studied in detail in this work. The W-O-N coatings were deposited by direct current (DC) sputtering to a thickness of ˜100 nm and the structural, compositional, optical and mechanical properties were characterized in order to gain a deeper understanding of the effects of nitrogen incorporation and chemical composition. All the W-O-N coatings fabricated under variable nitrogen gas flow rate were amorphous. X-ray photoelectron spectroscopy (XPS) and Rutherford backscattering spectrometry (RBS) measurements revealed that nitrogen incorporation is effective only for a nitrogen gas flow rates ?9 sccm. Optical characterization using ultraviolet-visible-near infrared (UV-VIS-NIR) spectroscopy and spectroscopic ellipsometry (SE) indicate that the nitrogen incorporation induced effects on the optical parameters is significant. The band gap (Eg) values decreased from ˜2.99 eV to ˜1.89 eV indicating a transition from insulating WO3 to metallic-like W-N phase. Nano-mechanical characterization using indentation revealed a corresponding change in mechanical properties; maximum values of 4.46 GPa and 98.5 GPa were noted for hardness and Young?s modulus, respectively. The results demonstrate a clear relationship between the mechanical, physical and optical properties of amorphous W-O-N nano-coatings. The correlation presented in this thesis could

Aerosol optical properties inferred from in-situ and path-averaged measurements

NASA Astrophysics Data System (ADS)

van Binsbergen, Sven A.; Grossmann, Peter; Cohen, Leo H.; van Eijk, Alexander M. J.; Stein, Karin U.

2017-09-01

This paper compares in-situ and path-averaged measurements of the electro-optical transmission, with emphasis on aerosol effects. The in-situ sensors consisted of optical particle counters (OPC) and a visibility meter, the path-averaged data was provided by a 7-wavelength transmissometer (MSRT) and a scintillometer (BLS). Data was collected at a test site in Northern Germany. A retrieval algorithm was developed to infer characteristics of the aerosol size distribution (Junge approximation) from the MSRT data. A comparison of the various sensors suggests that the optical particle counters are over-optimistic in their estimate of the transmission.

Optical increase of photo-integrated micro- and nano-periodic susceptibility lattices

NASA Astrophysics Data System (ADS)

Smirnov, Vitaly A.; Vostrikova, Liubov I.

2015-03-01

It is demonstrated that the nonlinear photo-integrated micro- and nano-periodic second-order susceptibility lattices with very small amplitudes which were preliminarily recorded using bi-chromatic powerful laser light in amorphous glass materials can be increased up to some orders of magnitude under the action of a simple coherent monochromatic radiation. The optical increase of the small lattices takes place independent of the polarization and direction of propagation of the optical amplifying radiation and is achieved at various wavelengths. The observed phenomenon is not be explained only by nonlinear wave interaction in medium and also may be related to the microscopic asymmetry processes of the optical transitions between local centers in an isotropic medium that leads to the appearance and growth of the all-optically induced small micro- and nano-periodic electrical charges separations inside the sample. Possible mechanisms that may be responsible for the observed effects in the studied phosphate glasses are discussed.

A novel optical fibre doped with the nano-material as InP

NASA Astrophysics Data System (ADS)

Chen, Xi; Lee, Ly Guat; Zhang, Ru

2007-11-01

As the key of these optical devices which are widely used in the communication system, high nonlinear optical fibre will play an important role in the future optical fibre communication. With recent growth of nano-technology, researchers are hoping to obtain some kinds of optical fibre by combining the optical fibre with the nanotechnology. According to this current situation, the optical fibre doped with nano-material as InP (indium phosphide) is manufactured by using the MCVD (modified chemical vapor deposition) technology after our comprehensive consideration of many relative factors. Proved by experiments, this novel optical fibre has an excellent waveguide characteristic. After a consideration of the model of this novel optical fibre, its propagation constant β has been simulated by using the FEM (finite element method), and the graphs of presentation of magnetic field of the core are also obtained. In accordance with the results, the effective refractive index n eff = 1.401 has be calculated. Both the calculated result and the simulated graphs are matching well with the test, and this result is a step-stone bridge for future research of nonlinear parameter on this novel optical fiber.

Thermo-optical dynamics in an optically pumped Photonic Crystal nano-cavity.

PubMed

Brunstein, M; Braive, R; Hostein, R; Beveratos, A; Rober-Philip, I; Sagnes, I; Karle, T J; Yacomotti, A M; Levenson, J A; Moreau, V; Tessier, G; De Wilde, Y

2009-09-14

Linear and non-linear thermo-optical dynamical regimes were investigated in a photonic crystal cavity. First, we have measured the thermal relaxation time in an InP-based nano-cavity with quantum dots in the presence of optical pumping. The experimental method presented here allows one to obtain the dynamics of temperature in a nanocavity based on reflectivity measurements of a cw probe beam coupled through an adiabatically tapered fiber. Characteristic times of 1.0+/-0.2 micros and 0.9+/-0.2 micros for the heating and the cooling processes were obtained. Finally, thermal dynamics were also investigated in a thermo-optical bistable regime. Switch-on/off times of 2 micros and 4 micros respectively were measured, which could be explained in terms of a simple non-linear dynamical representation.

Spectrally resolved chromatic confocal interferometry for one-shot nano-scale surface profilometry with several tens of micrometric depth range

NASA Astrophysics Data System (ADS)

Chen, Liang-Chia; Chen, Yi-Shiuan; Chang, Yi-Wei; Lin, Shyh-Tsong; Yeh, Sheng Lih

2013-01-01

In this research, new nano-scale measurement methodology based on spectrally-resolved chromatic confocal interferometry (SRCCI) was successfully developed by employing integration of chromatic confocal sectioning and spectrally-resolve white light interferometry (SRWLI) for microscopic three dimensional surface profilometry. The proposed chromatic confocal method (CCM) using a broad band while light in combination with a specially designed chromatic dispersion objective is capable of simultaneously acquiring multiple images at a large range of object depths to perform surface 3-D reconstruction by single image shot without vertical scanning and correspondingly achieving a high measurement depth range up to hundreds of micrometers. A Linnik-type interferometric configuration based on spectrally resolved white light interferometry is developed and integrated with the CCM to simultaneously achieve nanoscale axis resolution for the detection point. The white-light interferograms acquired at the exit plane of the spectrometer possess a continuous variation of wavelength along the chromaticity axis, in which the light intensity reaches to its peak when the optical path difference equals to zero between two optical arms. To examine the measurement accuracy of the developed system, a pre-calibrated accurate step height target with a total step height of 10.10 μm was measured. The experimental result shows that the maximum measurement error was verified to be less than 0.3% of the overall measuring height.

A model of optical trapping cold atoms using a metallic nano wire with surface plasmon effect

NASA Astrophysics Data System (ADS)

Thi Phuong Lan, Nguyen; Thi Nga, Do; Viet, Nguyen Ai

2016-06-01

In this work, we construct a new model of optical trapping cold atoms with a metallic nano wire by using surface plasmon effect generated by strong field of laser beams. Using the skin effect, we send a strong oscillated electromagnetic filed through the surface of a metallic nano wire. The local field generated by evanescent effect creates an effective attractive potential near the surface of metallic nano wires. The consideration of some possible boundary and frequency conditions might lead to non-trivial bound state solution for a cold atom. We discus also the case of the laser reflection optical trap with shell-core design, and compare our model with another recent schemes of cold atom optical traps using optical fibers and carbon nanotubes.

Understanding and applying open-path optical sensing data

NASA Astrophysics Data System (ADS)

Virag, Peter; Kricks, Robert J.

1999-02-01

During the last 10 years, open-path air monitors have evolved to yield reliable and effective measurements of single and multiple compounds on a real-time basis. To many individuals within the optical remote sensing community, the attributes of open-path and its the potential uses seem unlimited. Then why has the market has been stagnant for the last few years? The reason may center on how open-path information is applied and how well the end user understands that information. We constantly try to compare open-path data to risk/health or safety levels that are based for use at a single point and for a specific averaging period often far longer than a typical open-path data point. Often this approach is perceived as putting a square peg in a round hole. This perception may be well founded, as open-path data at times may need to go through extensive data manipulation and assumptions before it can be applied. This paper will review pervious open-path monitoring programs and their success in applying the data collected. We will also look at how open-path data is being currently used, some previous pitfalls in data use, alternate methods of data interpretation, and how open-path data can be best practically applied to fit current needs.

Optical properties study of nano-composite filled D shape photonic crystal fibre

NASA Astrophysics Data System (ADS)

Udaiyakumar, R.; Mohamed Junaid, K. A.; Janani, T.; Maheswar, R.; Yupapin, P.; Amiri, I. S.

2018-06-01

With the nano-composite materials gaining momentum in the optical field, a new nano-composite filled D shape Photonic Crystal Fiber (PCF) is designed and the various optical properties are investigated with help of Finite Element Method. In the proposed structure the D-shape PCF is made up of silica with embedded silver nanoparticles and air holes are distributed along the fibre. The designed fibre shows various optical properties such as dispersion, birefringence, beat length and loss with respect to wavelength and compared with different filling factor like 0.1, 0.3 and 0.5. From our estimation and comparative analysis, it has been proved that the fibre loss has been decreased with increasing filling factor. Further this also showed flat dispersion at maximum filling factor.

Nonlinear electro-optic tuning of plasmonic nano-filter

NASA Astrophysics Data System (ADS)

Kotb, Rehab; Ismail, Yehea; Swillam, Mohamed A.

2015-03-01

Efficient, easy and accurate tuning techniques to a plasmonic nano-filter are investigated. The proposed filter supports both blue and red shift in the resonance wavelength. By varying the refractive index with a very small change (in the order of 10-3), the resonance wavelength can be controlled efficiently. Using Pockels material, an electrical tuning to the response of the filter is demonstrated. In addition, the behavior of the proposed filter can be controlled optically using Kerr material. A new approach of multi-stage electro-optic controlling is introduced. By cascading two stages and filling the first stage with pockels material and the second stage with kerr material, the output response of the second stage can be controlled by controlling the output response of the first stage electrically. Due to the sharp response of the proposed filter, 60nm shift in the resonance wavelength per 10 voltages is achieved. This nano-filter has compact size, low loss, sharp response and wide range of tunabilty which is highly demandable in many biological and sensing applications.

Multi-scale theory-assisted nano-engineering of plasmonic-organic hybrid electro-optic device performance

NASA Astrophysics Data System (ADS)

Elder, Delwin L.; Johnson, Lewis E.; Tillack, Andreas F.; Robinson, Bruce H.; Haffner, Christian; Heni, Wolfgang; Hoessbacher, Claudia; Fedoryshyn, Yuriy; Salamin, Yannick; Baeuerle, Benedikt; Josten, Arne; Ayata, Masafumi; Koch, Ueli; Leuthold, Juerg; Dalton, Larry R.

2018-02-01

Multi-scale (correlated quantum and statistical mechanics) modeling methods have been advanced and employed to guide the improvement of organic electro-optic (OEO) materials, including by analyzing electric field poling induced electro-optic activity in nanoscopic plasmonic-organic hybrid (POH) waveguide devices. The analysis of in-device electro-optic activity emphasizes the importance of considering both the details of intermolecular interactions within organic electro-optic materials and interactions at interfaces between OEO materials and device architectures. Dramatic improvement in electro-optic device performance-including voltage-length performance, bandwidth, energy efficiency, and lower optical losses have been realized. These improvements are critical to applications in telecommunications, computing, sensor technology, and metrology. Multi-scale modeling methods illustrate the complexity of improving the electro-optic activity of organic materials, including the necessity of considering the trade-off between improving poling-induced acentric order through chromophore modification and the reduction of chromophore number density associated with such modification. Computational simulations also emphasize the importance of developing chromophore modifications that serve multiple purposes including matrix hardening for enhanced thermal and photochemical stability, control of matrix dimensionality, influence on material viscoelasticity, improvement of chromophore molecular hyperpolarizability, control of material dielectric permittivity and index of refraction properties, and control of material conductance. Consideration of new device architectures is critical to the implementation of chipscale integration of electronics and photonics and achieving the high bandwidths for applications such as next generation (e.g., 5G) telecommunications.

Observing Optical Plasmons on a Single Nanometer Scale

PubMed Central

Cohen, Moshik; Shavit, Reuven; Zalevsky, Zeev

2014-01-01

The exceptional capability of plasmonic structures to confine light into deep subwavelength volumes has fashioned rapid expansion of interest from both fundamental and applicative perspectives. Surface plasmon nanophotonics enables to investigate light - matter interaction in deep nanoscale and harness electromagnetic and quantum properties of materials, thus opening pathways for tremendous potential applications. However, imaging optical plasmonic waves on a single nanometer scale is yet a substantial challenge mainly due to size and energy considerations. Here, for the first time, we use Kelvin Probe Force Microscopy (KPFM) under optical illumination to image and characterize plasmonic modes. We experimentally demonstrate unprecedented spatial resolution and measurement sensitivity both on the order of a single nanometer. By comparing experimentally obtained images with theoretical calculation results, we show that KPFM maps may provide valuable information on the phase of the optical near field. Additionally, we propose a theoretical model for the relation between surface plasmons and the material workfunction measured by KPFM. Our findings provide the path for using KPFM for high resolution measurements of optical plasmons, prompting the scientific frontier towards quantum plasmonic imaging on submolecular scales. PMID:24556874

Sub-diffraction nano manipulation using STED AFM.

PubMed

Chacko, Jenu Varghese; Canale, Claudio; Harke, Benjamin; Diaspro, Alberto

2013-01-01

In the last two decades, nano manipulation has been recognized as a potential tool of scientific interest especially in nanotechnology and nano-robotics. Contemporary optical microscopy (super resolution) techniques have also reached the nanometer scale resolution to visualize this and hence a combination of super resolution aided nano manipulation ineluctably gives a new perspective to the scenario. Here we demonstrate how specificity and rapid determination of structures provided by stimulated emission depletion (STED) microscope can aid another microscopic tool with capability of mechanical manoeuvring, like an atomic force microscope (AFM) to get topological information or to target nano scaled materials. We also give proof of principle on how high-resolution real time visualization can improve nano manipulation capability within a dense sample, and how STED-AFM is an optimal combination for this job. With these evidences, this article points to future precise nano dissections and maybe even to a nano-snooker game with an AFM tip and fluorospheres.

Optical spring effect in nanoelectromechanical systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tian, Feng; Zhou, Guangya, E-mail: mpezgy@nus.edu.sg; Du, Yu

2014-08-11

In this Letter, we report a hybrid system consisting of nano-optical and nano-mechanical springs, in which the optical spring effect works to adjust the mechanical frequency of a nanoelectromechanical systems resonator. Nano-scale folded beams are fabricated as the mechanical springs and double-coupled one-dimensional photonic crystal cavities are used to pump the “optical spring.” The dynamic characteristics of this hybrid system are measured and analyzed at both low and high input optical powers. This study leads the physical phenomenon of optomechanics in complex nano-opto-electro-mechanical systems (NOEMS) and could benefit the future applications of NOEMS in chip-level communication and sensing.

Multimodal non-linear optical imaging for the investigation of drug nano-/microcrystal-cell interactions.

PubMed

Darville, Nicolas; Saarinen, Jukka; Isomäki, Antti; Khriachtchev, Leonid; Cleeren, Dirk; Sterkens, Patrick; van Heerden, Marjolein; Annaert, Pieter; Peltonen, Leena; Santos, Hélder A; Strachan, Clare J; Van den Mooter, Guy

2015-10-01

Drug nano-/microcrystals are being used for sustained parenteral drug release, but safety and efficacy concerns persist as the knowledge of the in vivo fate of long-living particulates is limited. There is a need for techniques enabling the visualization of drug nano-/microcrystals in biological matrices. The aim of this work was to explore the potential of coherent anti-Stokes Raman scattering (CARS) microscopy, supported by other non-linear optical methods, as an emerging tool for the investigation of cellular and tissue interactions of unlabeled and non-fluorescent nano-/microcrystals. Raman and CARS spectra of the prodrug paliperidone palmitate (PP), paliperidone (PAL) and several suspension stabilizers were recorded. PP nano-/microcrystals were incubated with RAW 264.7 macrophages in vitro and their cellular disposition was investigated using a fully-integrated multimodal non-linear optical imaging platform. Suitable anti-Stokes shifts (CH stretching) were identified for selective CARS imaging. CARS microscopy was successfully applied for the selective three-dimensional, non-perturbative and real-time imaging of unlabeled PP nano-/microcrystals having dimensions larger than the optical lateral resolution of approximately 400nm, in relation to the cellular framework in cell cultures and ex vivo in histological sections. In conclusion, CARS microscopy enables the non-invasive and label-free imaging of (sub)micron-sized (pro-)drug crystals in complex biological matrices and could provide vital information on poorly understood nano-/microcrystal-cell interactions in future. Copyright © 2015 Elsevier B.V. All rights reserved.

A 2-dimensional optical architecture for solving Hamiltonian path problem based on micro ring resonators

NASA Astrophysics Data System (ADS)

Shakeri, Nadim; Jalili, Saeed; Ahmadi, Vahid; Rasoulzadeh Zali, Aref; Goliaei, Sama

2015-01-01

The problem of finding the Hamiltonian path in a graph, or deciding whether a graph has a Hamiltonian path or not, is an NP-complete problem. No exact solution has been found yet, to solve this problem using polynomial amount of time and space. In this paper, we propose a two dimensional (2-D) optical architecture based on optical electronic devices such as micro ring resonators, optical circulators and MEMS based mirror (MEMS-M) to solve the Hamiltonian Path Problem, for undirected graphs in linear time. It uses a heuristic algorithm and employs n+1 different wavelengths of a light ray, to check whether a Hamiltonian path exists or not on a graph with n vertices. Then if a Hamiltonian path exists, it reports the path. The device complexity of the proposed architecture is O(n2).

Observing non-equilibrium state of transport through graphene channel at the nano-second time-scale

NASA Astrophysics Data System (ADS)

Mishra, Abhishek; Meersha, Adil; Raghavan, Srinivasan; Shrivastava, Mayank

2017-12-01

Electrical performance of a graphene FET is drastically affected by electron-phonon inelastic scattering. At high electric fields, the out-of-equilibrium population of optical phonons equilibrates by emitting acoustic phonons, which dissipate the energy to heat sinks. The equilibration time of the process is governed by thermal diffusion time, which is few nano-seconds for a typical graphene FET. The nano-second time-scale of the process keeps it elusive to conventional steady-state or DC measurement systems. Here, we employ a time-domain reflectometry-based technique to electrically probe the device for few nano-seconds and investigate the non-equilibrium state. For the first time, the transient nature of electrical transport through graphene FET is revealed. A maximum change of 35% in current and 50% in contact resistance is recorded over a time span of 8 ns, while operating graphene FET at a current density of 1 mA/μm. The study highlights the role of intrinsic heating (scattering) in deciding metal-graphene contact resistance and transport through the graphene channel.

Peano-like paths for subaperture polishing of optical aspherical surfaces.

PubMed

Tam, Hon-Yuen; Cheng, Haobo; Dong, Zhichao

2013-05-20

Polishing can be more uniform if the polishing path provides uniform coverage of the surface. It is known that Peano paths can provide uniform coverage of planar surfaces. Peano paths also contain short path segments and turns: (1) all path segments have the same length, (2) path segments are mutually orthogonal at the turns, and (3) path segments and turns are uniformity distributed over the domain surface. These make Peano paths an attractive candidate among polishing tool paths because they enhance multidirectional approaches of the tool to each surface location. A method for constructing Peano paths for uniform coverage of aspherical surfaces is proposed in this paper. When mapped to the aspherical surface, the path also contains short path segments and turns, and the above attributes are approximately preserved. Attention is paid so that the path segments are still well distributed near the vertex of the surface. The proposed tool path was used in the polishing of a number of parabolic BK7 specimens using magnetorheological finishing (MRF) and pitch with cerium oxide. The results were rather good for optical lenses and confirm that a Peano-like path was useful for polishing, for MRF, and for pitch polishing. In the latter case, the surface roughness achieved was 0.91 nm according to WYKO measurement.

Molecular Imaging of Kerogen and Minerals in Shale Rocks across Micro- and Nano- Scales

NASA Astrophysics Data System (ADS)

Hao, Z.; Bechtel, H.; Sannibale, F.; Kneafsey, T. J.; Gilbert, B.; Nico, P. S.

2016-12-01

Fourier transform infrared (FTIR) spectroscopy is a reliable and non-destructive quantitative method to evaluate mineralogy and kerogen content / maturity of shale rocks, although it is traditionally difficult to assess the organic and mineralogical heterogeneity at micrometer and nanometer scales due to the diffraction limit of the infrared light. However, it is truly at these scales that the kerogen and mineral content and their formation in share rocks determines the quality of shale gas reserve, the gas flow mechanisms and the gas production. Therefore, it's necessary to develop new approaches which can image across both micro- and nano- scales. In this presentation, we will describe two new molecular imaging approaches to obtain kerogen and mineral information in shale rocks at the unprecedented high spatial resolution, and a cross-scale quantitative multivariate analysis method to provide rapid geochemical characterization of large size samples. The two imaging approaches are enhanced at nearfield respectively by a Ge-hemisphere (GE) and by a metallic scanning probe (SINS). The GE method is a modified microscopic attenuated total reflectance (ATR) method which rapidly captures a chemical image of the shale rock surface at 1 to 5 micrometer resolution with a large field of view of 600 X 600 micrometer, while the SINS probes the surface at 20 nm resolution which provides a chemically "deconvoluted" map at the nano-pore level. The detailed geochemical distribution at nanoscale is then used to build a machine learning model to generate self-calibrated chemical distribution map at micrometer scale with the input of the GE images. A number of geochemical contents across these two important scales are observed and analyzed, including the minerals (oxides, carbonates, sulphides), the organics (carbohydrates, aromatics), and the absorbed gases. These approaches are self-calibrated, optics friendly and non-destructive, so they hold the potential to monitor shale gas

Multi-scale Modeling and Analysis of Nano-RFID Systems on HPC Setup

NASA Astrophysics Data System (ADS)

Pathak, Rohit; Joshi, Satyadhar

In this paper we have worked out on some the complex modeling aspects such as Multi Scale modeling, MATLAB Sugar based modeling and have shown the complexities involved in the analysis of Nano RFID (Radio Frequency Identification) systems. We have shown the modeling and simulation and demonstrated some novel ideas and library development for Nano RFID. Multi scale modeling plays a very important role in nanotech enabled devices properties of which cannot be explained sometimes by abstraction level theories. Reliability and packaging still remains one the major hindrances in practical implementation of Nano RFID based devices. And to work on them modeling and simulation will play a very important role. CNTs is the future low power material that will replace CMOS and its integration with CMOS, MEMS circuitry will play an important role in realizing the true power in Nano RFID systems. RFID based on innovations in nanotechnology has been shown. MEMS modeling of Antenna, sensors and its integration in the circuitry has been shown. Thus incorporating this we can design a Nano-RFID which can be used in areas like human implantation and complex banking applications. We have proposed modeling of RFID using the concept of multi scale modeling to accurately predict its properties. Also we give the modeling of MEMS devices that are proposed recently that can see possible application in RFID. We have also covered the applications and the advantages of Nano RFID in various areas. RF MEMS has been matured and its devices are being successfully commercialized but taking it to limits of nano domains and integration with singly chip RFID needs a novel approach which is being proposed. We have modeled MEMS based transponder and shown the distribution for multi scale modeling for Nano RFID.

In Conversation with Jim Schuck: Nano-optics

ScienceCinema

Jim Schuck and Alice Egan

2017-12-09

Sponsored by Berkeley Lab's Materials Sciences Division (MSD), "In Conversation with" is a next generation science seminar series. Host Alice Egan is the assistant to MSD Director Miquel Salmeron. Alice conducts a fun and informative interview, touching on the lives and work of the guest. The first In Conversation With took place July 9 with Jim Schuck, a staff scientist in the Molecular Foundry's Imaging and Manipulation Facility as our first guest. He discussed the world of Nano-optics.

In Conversation with Jim Schuck: Nano-optics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jim Schuck and Alice Egan

Sponsored by Berkeley Lab's Materials Sciences Division (MSD), "In Conversation with" is a next generation science seminar series. Host Alice Egan is the assistant to MSD Director Miquel Salmeron. Alice conducts a fun and informative interview, touching on the lives and work of the guest. The first In Conversation With took place July 9 with Jim Schuck, a staff scientist in the Molecular Foundry's Imaging and Manipulation Facility as our first guest. He discussed the world of Nano-optics.

Microscopic optical path length difference and polarization measurement system for cell analysis

NASA Astrophysics Data System (ADS)

Satake, H.; Ikeda, K.; Kowa, H.; Hoshiba, T.; Watanabe, E.

2018-03-01

In recent years, noninvasive, nonstaining, and nondestructive quantitative cell measurement techniques have become increasingly important in the medical field. These cell measurement techniques enable the quantitative analysis of living cells, and are therefore applied to various cell identification processes, such as those determining the passage number limit during cell culturing in regenerative medicine. To enable cell measurement, we developed a quantitative microscopic phase imaging system based on a Mach-Zehnder interferometer that measures the optical path length difference distribution without phase unwrapping using optical phase locking. The applicability of our phase imaging system was demonstrated by successful identification of breast cancer cells amongst normal cells. However, the cell identification method using this phase imaging system exhibited a false identification rate of approximately 7%. In this study, we implemented a polarimetric imaging system by introducing a polarimetric module to one arm of the Mach-Zehnder interferometer of our conventional phase imaging system. This module was comprised of a quarter wave plate and a rotational polarizer on the illumination side of the sample, and a linear polarizer on the optical detector side. In addition, we developed correction methods for the measurement errors of the optical path length and birefringence phase differences that arose through the influence of elements other than cells, such as the Petri dish. As the Petri dish holding the fluid specimens was transparent, it did not affect the amplitude information; however, the optical path length and birefringence phase differences were affected. Therefore, we proposed correction of the optical path length and birefringence phase for the influence of elements other than cells, as a prerequisite for obtaining highly precise phase and polarimetric images.

Optical Absorption Spectra of Nuclear Filters Modified by Deposition of Silver Nano- and Microparticles

NASA Astrophysics Data System (ADS)

Smolyanskii, A. S.; Kozlova, N. V.; Zheltova, A. V.; Aksyutina, A. S.; Shvedov, A. S.; Lakeev, S. G.

2015-07-01

Light scattering and interference patterns are studied in the optical absorption spectra of nuclear filters based on polyethylene terephthalate fi lms modifi ed by dry aerosol deposition of silver nano- and microparticles. Surface plasmon polaritons and localized plasmons formed by the passage of light through porous silver films are found to have an effect on the diffraction and interference modes. The thickness of silver nano- and microparticle coatings on the surface of the nuclear fi lters was determined from the shift in the interference patterns in the optical absorption spectra of the modified nuclear filters relative to the original nuclear filters. A correlation was found between the estimated coating thickness and the average surface roughness of the nuclear filters modified by layers of silver nano- and microparticles.

Tunable nano-scale graphene-based devices in mid-infrared wavelengths composed of cylindrical resonators

NASA Astrophysics Data System (ADS)

Asgari, Somayyeh; Ghattan Kashani, Zahra; Granpayeh, Nosrat

2018-04-01

The performances of three optical devices including a refractive index sensor, a power splitter, and a 4-channel multi/demultiplexer based on graphene cylindrical resonators are proposed, analyzed, and simulated numerically by using the finite-difference time-domain method. The proposed sensor operates on the principle of the shift in resonance wavelength with a change in the refractive index of dielectric materials. The sensor sensitivity has been numerically derived. In addition, the performances of the power splitter and the multi/demultiplexer based on the variation of the resonance wavelengths of cylindrical resonator have been thoroughly investigated. The simulation results are in good agreement with the theoretical ones. Our studies demonstrate that the graphene based ultra-compact, nano-scale devices can be improved to be used as photonic integrated devices, optical switching, and logic gates.

Nano-scale processes behind ion-beam cancer therapy

NASA Astrophysics Data System (ADS)

Surdutovich, Eugene; Garcia, Gustavo; Mason, Nigel; Solov'yov, Andrey V.

2016-04-01

This topical issue collates a series of papers based on new data reported at the third Nano-IBCT Conference of the COST Action MP1002: Nanoscale Insights into Ion Beam Cancer Therapy, held in Boppard, Germany, from October 27th to October 31st, 2014. The Nano-IBCT COST Action was launched in December 2010 and brought together more than 300 experts from different disciplines (physics, chemistry, biology) with specialists in radiation damage of biological matter from hadron-therapy centres, and medical institutions. This meeting followed the first and the second conferences of the Action held in October 2011 in Caen, France and in May 2013 in Sopot, Poland respectively. This conference series provided a focus for the European research community and has highlighted the pioneering research into the fundamental processes underpinning ion beam cancer therapy. Contribution to the Topical Issue "COST Action Nano-IBCT: Nano-scale Processes Behind Ion-Beam Cancer Therapy", edited by Andrey V. Solov'yov, Nigel Mason, Gustavo Garcia and Eugene Surdutovich.

Temperature dependence of nonlinear optical properties in Li doped nano-carbon bowl material

NASA Astrophysics Data System (ADS)

Li, Wei-qi; Zhou, Xin; Chang, Ying; Quan Tian, Wei; Sun, Xiu-Dong

2013-04-01

The mechanism for change of nonlinear optical (NLO) properties with temperature is proposed for a nonlinear optical material, Li doped curved nano-carbon bowl. Four stable conformations of Li doped corannulene were located and their electronic properties were investigated in detail. The NLO response of those Li doped conformations varies with relative position of doping agent on the curved carbon surface of corannulene. Conversion among those Li doped conformations, which could be controlled by temperature, changes the NLO response of bulk material. Thus, conformation change of alkali metal doped carbon nano-material with temperature rationalizes the variation of NLO properties of those materials.

[Study on preparation of composite nano-scale Fe3O4 for phosphorus control].

PubMed

Li, Lei; Pan, Gang; Chen, Hao

2010-03-01

Composite nano-scale Fe3O4 particles were prepared in sodium carboxymethyl cellulose (CMC) solution by the oxidation deposition method. The adsorptions of phosphorus by micro-scale Fe3O4 and composite nano-scale Fe3O4 were investigated in water and soil, and the role of cellulase in the adsorption of composite nano-scale Fe3O4 was studied. Kinetic tests indicated that the equilibrium adsorption capacity of phosphorous on the composite nano-scale Fe3O4 (2.1 mg/g) was less than that of micro-scale Fe3O4 (3.2 mg/g). When cellulase was added to the solution of composite nano-scale Fe3O4 to degrade CMC, the removal rate of P by the nanoparticles (86%) was enhanced to the same level as the microparticles (90%). In the column tests, when the composite nano-scale Fe3O4 suspension was introduced in the downflow mode through the soil column, 72% of Fe3O4 penetrated through the soil bed under gravity. In contrast, the micro-scale Fe3O4 failed to pass through the soil column. The retention rate of P was 45% in the soil column when treated by the CMC-stabilized nanoparticles, in comparison with only 30% for the untreated soil column, however it could be improved to 74% in the soil column when treated by both the CMC-stabilized nanoparticles and cellulase, which degraded CMC after the nanoparticles were delivered into the soil.

Non-common path aberration correction in an adaptive optics scanning ophthalmoscope.

PubMed

Sulai, Yusufu N; Dubra, Alfredo

2014-09-01

The correction of non-common path aberrations (NCPAs) between the imaging and wavefront sensing channel in a confocal scanning adaptive optics ophthalmoscope is demonstrated. NCPA correction is achieved by maximizing an image sharpness metric while the confocal detection aperture is temporarily removed, effectively minimizing the monochromatic aberrations in the illumination path of the imaging channel. Comparison of NCPA estimated using zonal and modal orthogonal wavefront corrector bases provided wavefronts that differ by ~λ/20 in root-mean-squared (~λ/30 standard deviation). Sequential insertion of a cylindrical lens in the illumination and light collection paths of the imaging channel was used to compare image resolution after changing the wavefront correction to maximize image sharpness and intensity metrics. Finally, the NCPA correction was incorporated into the closed-loop adaptive optics control by biasing the wavefront sensor signals without reducing its bandwidth.

Non-common path aberration correction in an adaptive optics scanning ophthalmoscope

PubMed Central

Sulai, Yusufu N.; Dubra, Alfredo

2014-01-01

The correction of non-common path aberrations (NCPAs) between the imaging and wavefront sensing channel in a confocal scanning adaptive optics ophthalmoscope is demonstrated. NCPA correction is achieved by maximizing an image sharpness metric while the confocal detection aperture is temporarily removed, effectively minimizing the monochromatic aberrations in the illumination path of the imaging channel. Comparison of NCPA estimated using zonal and modal orthogonal wavefront corrector bases provided wavefronts that differ by ~λ/20 in root-mean-squared (~λ/30 standard deviation). Sequential insertion of a cylindrical lens in the illumination and light collection paths of the imaging channel was used to compare image resolution after changing the wavefront correction to maximize image sharpness and intensity metrics. Finally, the NCPA correction was incorporated into the closed-loop adaptive optics control by biasing the wavefront sensor signals without reducing its bandwidth. PMID:25401020

128×128 three-dimensional MEMS optical switch module with simultaneous optical path connection for optical cross-connect systems.

PubMed

Mizukami, Masato; Yamaguchi, Joji; Nemoto, Naru; Kawajiri, Yuko; Hirata, Hirooki; Uchiyama, Shingo; Makihara, Mitsuhiro; Sakata, Tomomi; Shimoyama, Nobuhiro; Oda, Kazuhiro

2011-07-20

A 128×128 three-dimensional MEMS optical switch module and a switching-control algorithm for high-speed connection and optical power stabilization are described. A prototype switch module enables the simultaneous switching of all optical paths. The insertion loss is less than 4.6 dB and is 2.3 dB on average. The switching time is less than 38 ms and is 8 ms on average. We confirmed that the maximum optical power can be obtained and optical power stabilization control is possible. The results confirm that the module is suitable for practical use in optical cross-connect systems. © 2011 Optical Society of America

Improvement in crystal quality and optical properties of n-type GaN employing nano-scale SiO2 patterned n-type GaN substrate.

PubMed

Jo, Min Sung; Sadasivam, Karthikeyan Giri; Tawfik, Wael Z; Yang, Seung Bea; Lee, Jung Ju; Ha, Jun Seok; Moon, Young Boo; Ryu, Sang Wan; Lee, June Key

2013-01-01

n-type GaN epitaxial layers were regrown on the patterned n-type GaN substrate (PNS) with different size of silicon dioxide (SiO2) nano dots to improve the crystal quality and optical properties. PNS with SiO2 nano dots promotes epitaxial lateral overgrowth (ELOG) for defect reduction and also acts as a light scattering point. Transmission electron microscopy (TEM) analysis suggested that PNS with SiO2 nano dots have superior crystalline properties. Hall measurements indicated that incrementing values in electron mobility were clear indication of reduction in threading dislocation and it was confirmed by TEM analysis. Photoluminescence (PL) intensity was enhanced by 2.0 times and 3.1 times for 1-step and 2-step PNS, respectively.

Electrochemical micro/nano-machining: principles and practices.

PubMed

Zhan, Dongping; Han, Lianhuan; Zhang, Jie; He, Quanfeng; Tian, Zhao-Wu; Tian, Zhong-Qun

2017-03-06

Micro/nano-machining (MNM) is becoming the cutting-edge of high-tech manufacturing because of the increasing industrial demand for supersmooth surfaces and functional three-dimensional micro/nano-structures (3D-MNS) in ultra-large scale integrated circuits, microelectromechanical systems, miniaturized total analysis systems, precision optics, and so on. Taking advantage of no tool wear, no surface stress, environmental friendliness, simple operation, and low cost, electrochemical micro/nano-machining (EC-MNM) has an irreplaceable role in MNM. This comprehensive review presents the state-of-art of EC-MNM techniques for direct writing, surface planarization and polishing, and 3D-MNS fabrications. The key point of EC-MNM is to confine electrochemical reactions at the micro/nano-meter scale. This review will bring together various solutions to "confined reaction" ranging from electrochemical principles through technical characteristics to relevant applications.

High pressure effect on optical gain in type-II InGaAs/GaAsSb nano-heterostructure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yadav, Nisha; Nirmal, H. K.; Yadav, Rashmi

This paper reports the simulation of optical gain in type-II InGaAs/GaAsSb quantum well based nano-scale heterostructure. In order to simulate the optical gain, the heterostructure has been modeled with the help of six band k.p method. The 6 × 6 diagonalized k.p Hamiltonian has been solved to evaluate the valence sub-bands (i.e. light and heavy hole energies); and then optical matrix elements and optical gain within TE (Transverse Electric) mode has been calculated. The results obtained suggest that peak optical gain of the order of ∼ 9000 /cm in the heterostructure can be achieved at the lasing wavelength ∼ 1.95 µmmore » (SWIR region). The application of high pressure (2 and 5 GPa) on the structure shows that the gain as well as lasing wavelength both approach to higher values. Thus, the structure can be tuned externally by the application of high pressure.« less

In situ thermomechanical testing methods for micro/nano-scale materials.

PubMed

Kang, Wonmo; Merrill, Marriner; Wheeler, Jeffrey M

2017-02-23

The advance of micro/nanotechnology in energy-harvesting, micropower, electronic devices, and transducers for automobile and aerospace applications has led to the need for accurate thermomechanical characterization of micro/nano-scale materials to ensure their reliability and performance. This persistent need has driven various efforts to develop innovative experimental techniques that overcome the critical challenges associated with precise mechanical and thermal control of micro/nano-scale specimens during material characterization. Here we review recent progress in the development of thermomechanical testing methods from miniaturized versions of conventional macroscopic test systems to the current state of the art of in situ uniaxial testing capabilities in electron microscopes utilizing either indentation-based microcompression or integrated microsystems. We discuss the major advantages/disadvantages of these methods with respect to specimen size, range of temperature control, ease of experimentation and resolution of the measurements. We also identify key challenges in each method. Finally, we summarize some of the important discoveries that have been made using in situ thermomechanical testing and the exciting research opportunities still to come in micro/nano-scale materials.

Single and dual fiber nano-tip optical tweezers: trapping and analysis.

PubMed

Decombe, Jean-Baptiste; Huant, Serge; Fick, Jochen

2013-12-16

An original optical tweezers using one or two chemically etched fiber nano-tips is developed. We demonstrate optical trapping of 1 micrometer polystyrene spheres at optical powers down to 2 mW. Harmonic trap potentials were found in the case of dual fiber tweezers by analyzing the trapped particle position fluctuations. The trap stiffness was deduced using three different models. Consistent values of up to 1 fN/nm were found. The stiffness linearly decreases with decreasing light intensity and increasing fiber tip-to-tip distance.

Turbulence effects in a horizontal propagation path close to ground: implications for optics detection

NASA Astrophysics Data System (ADS)

Sjöqvist, Lars; Allard, Lars; Gustafsson, Ove; Henriksson, Markus; Pettersson, Magnus

2011-11-01

Atmospheric turbulence effects close to ground may affect the performance of laser based systems severely. The variations in the refractive index along the propagation path cause effects such as beam wander, intensity fluctuations (scintillations) and beam broadening. Typical geometries of interest for optics detection include nearly horizontal propagation paths close to the ground and up to kilometre distance to the target. The scintillations and beam wander affect the performance in terms of detection probability and false alarm rate. Of interest is to study the influence of turbulence in optics detection applications. In a field trial atmospheric turbulence effects along a 1 kilometre horizontal propagation path were studied using a diode laser with a rectangular beam profile operating at 0.8 micrometer wavelength. Single-path beam characteristics were registered and analysed using photodetectors arranged in horizontal and vertical directions. The turbulence strength along the path was determined using a scintillometer and single-point ultrasonic anemometers. Strong scintillation effects were observed as a function of the turbulence strength and amplitude characteristics were fitted to model distributions. In addition to the single-path analysis double-path measurements were carried out on different targets. Experimental results are compared with existing theoretical turbulence laser beam propagation models. The results show that influence from scintillations needs to be considered when predicting performance in optics detection applications.

Astigmatism corrected common path probe for optical coherence tomography.

PubMed

Singh, Kanwarpal; Yamada, Daisuke; Tearney, Guillermo

2017-03-01

Optical coherence tomography (OCT) catheters for intraluminal imaging are subject to various artifacts due to reference-sample arm dispersion imbalances and sample arm beam astigmatism. The goal of this work was to develop a probe that minimizes such artifacts. Our probe was fabricated using a single mode fiber at the tip of which a glass spacer and graded index objective lens were spliced to achieve the desired focal distance. The signal was reflected using a curved reflector to correct for astigmatism caused by the thin, protective, transparent sheath that surrounds the optics. The probe design was optimized using Zemax, a commercially available optical design software. Common path interferometric operation was achieved using Fresnel reflection from the tip of the focusing graded index objective lens. The performance of the probe was tested using a custom designed spectrometer-based OCT system. The probe achieved an axial resolution of 15.6 μm in air, a lateral resolution 33 μm, and a sensitivity of 103 dB. A scattering tissue phantom was imaged to test the performance of the probe for astigmatism correction. Images of the phantom confirmed that this common-path, astigmatism-corrected OCT imaging probe had minimal artifacts in the axial, and lateral dimensions. In this work, we developed an astigmatism-corrected, common path probe that minimizes artifacts associated with standard OCT probes. This design may be useful for OCT applications that require high axial and lateral resolutions. Lasers Surg. Med. 49:312-318, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Wave-optical assessment of alignment tolerances in nano-focusing with ellipsoidal mirror

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yumoto, Hirokatsu, E-mail: yumoto@spring8.or.jp; Koyama, Takahisa; Matsuyama, Satoshi

2016-01-28

High-precision ellipsoidal mirrors, which can efficiently focus X-rays to the nanometer dimension with a mirror, have not been realized because of the difficulties in the fabrication process. The purpose of our study was to develop nano-focusing ellipsoidal mirrors in the hard X-ray region. We developed a wave-optical focusing simulator for investigating alignment tolerances in nano-focusing with a designed ellipsoidal mirror, which produce a diffraction-limited focus size of 30 × 35 nm{sup 2} in full width at half maximum at an X-ray energy of 7 keV. The simulator can calculate focusing intensity distributions around the focal point under conditions of misalignment. Themore » wave-optical simulator enabled the calculation of interference intensity distributions, which cannot be predicted by the conventional ray-trace method. The alignment conditions with a focal length error of ≲ ±10 µm, incident angle error of ≲ ±0.5 µrad, and in-plane rotation angle error of ≲ ±0.25 µrad must be satisfied for nano-focusing.« less

Multi-Modal Nano-Probes for Radionuclide and 5-color Near Infrared Optical Lymphatic Imaging

PubMed Central

Kobayashi, Hisataka; Koyama, Yoshinori; Barrett, Tristan; Hama, Yukihiro; Regino, Celeste A. S.; Shin, In Soo; Jang, Beom-Su; Le, Nhat; Paik, Chang H.; Choyke, Peter L.; Urano, Yasuteru

2008-01-01

Current contrast agents generally have one function and can only be imaged in monochrome, therefore, the majority of imaging methods can only impart uniparametric information. A single nano-particle has the potential to be loaded with multiple payloads. Such multi-modality probes have the ability to be imaged by more than one imaging technique, which could compensate for the weakness or even combine the advantages of each individual modality. Furthermore, optical imaging using different optical probes enables us to achieve multi-color in vivo imaging, wherein multiple parameters can be read from a single image. To allow differentiation of multiple optical signals in vivo, each probe should have a close but different near infrared emission. To this end, we synthesized nano-probes with multi-modal and multi-color potential, which employed a polyamidoamine dendrimer platform linked to both radionuclides and optical probes, permitting dual-modality scintigraphic and 5-color near infrared optical lymphatic imaging using a multiple excitation spectrally-resolved fluorescence imaging technique. PMID:19079788

Modeling heading and path perception from optic flow in the case of independently moving objects

PubMed Central

Raudies, Florian; Neumann, Heiko

2013-01-01

Humans are usually accurate when estimating heading or path from optic flow, even in the presence of independently moving objects (IMOs) in an otherwise rigid scene. To invoke significant biases in perceived heading, IMOs have to be large and obscure the focus of expansion (FOE) in the image plane, which is the point of approach. For the estimation of path during curvilinear self-motion no significant biases were found in the presence of IMOs. What makes humans robust in their estimation of heading or path using optic flow? We derive analytical models of optic flow for linear and curvilinear self-motion using geometric scene models. Heading biases of a linear least squares method, which builds upon these analytical models, are large, larger than those reported for humans. This motivated us to study segmentation cues that are available from optic flow. We derive models of accretion/deletion, expansion/contraction, acceleration/deceleration, local spatial curvature, and local temporal curvature, to be used as cues to segment an IMO from the background. Integrating these segmentation cues into our method of estimating heading or path now explains human psychophysical data and extends, as well as unifies, previous investigations. Our analysis suggests that various cues available from optic flow help to segment IMOs and, thus, make humans' heading and path perception robust in the presence of such IMOs. PMID:23554589

Mid-IR colloidal quantum dot detectors enhanced by optical nano-antennas

NASA Astrophysics Data System (ADS)

Yifat, Yuval; Ackerman, Matthew; Guyot-Sionnest, Philippe

2017-01-01

We report the fabrication of a colloidal quantum dot based photodetector designed for the 3-5 μm mid infrared wavelength range incorporated with optical nano-antenna arrays to enhance the photocurrent. The fabricated arrays exhibit a resonant behavior dependent on the length of the nano-antenna rods, in good agreement with numerical simulation. The device exhibits a three-fold increase in the spectral photoresponse compared to a photodetector device without antennas, and the resonance is polarized parallel to the antenna orientation. We numerically estimate the device quantum efficiency and investigate its bias dependence.

The CHARA array adaptive optics I: common-path optical and mechanical design, and preliminary on-sky results

NASA Astrophysics Data System (ADS)

Che, Xiao; Sturmann, Laszlo; Monnier, John D.; ten Brummelaar, Theo A.; Sturmann, Judit; Ridgway, Stephen T.; Ireland, Michael J.; Turner, Nils H.; McAlister, Harold A.

2014-07-01

The CHARA array is an optical interferometer with six 1-meter diameter telescopes, providing baselines from 33 to 331 meters. With sub-milliarcsecond angular resolution, its versatile visible and near infrared combiners offer a unique angle of studying nearby stellar systems by spatially resolving their detailed structures. To improve the sensitivity and scientific throughput, the CHARA array was funded by NSF-ATI in 2011 to install adaptive optics (AO) systems on all six telescopes. The initial grant covers Phase I of the AO systems, which includes on-telescope Wavefront Sensors (WFS) and non-common-path (NCP) error correction. Meanwhile we are seeking funding for Phase II which will add large Deformable Mirrors on telescopes to close the full AO loop. The corrections of NCP error and static aberrations in the optical system beyond the WFS are described in the second paper of this series. This paper describes the design of the common-path optical system and the on-telescope WFS, and shows the on-sky commissioning results.

Plasmonic excitation-assisted optical and electric enhancement in ultra-thin solar cells: the influence of nano-strip cross section

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sabaeian, Mohammad, E-mail: sabaiean@scu.ac.ir; Heydari, Mehdi; Ajamgard, Narges

The effects of Ag nano-strips with triangle, rectangular and trapezoid cross sections on the optical absorption, generation rate, and short-circuit current density of ultra-thin solar cells were investigated. By putting the nano-strips as a grating structure on the top of the solar cells, the waveguide, surface plasmon polariton (SPP), and localized surface plasmon (LSP) modes, which are excited with the assistance of nano-strips, were evaluated in TE and TM polarizations. The results show, firstly, the TM modes are more influential than TE modes in optical and electrical properties enhancement of solar cell, because of plasmonic excitations in TM mode. Secondly,more » the trapezoid nano-strips reveal noticeable impact on the optical absorption, generation rate, and short-circuit current density enhancement than triangle and rectangular ones. In particular, the absorption of long wavelengths which is a challenge in ultra-thin solar cells is significantly improved by using Ag trapezoid nano-strips.« less

Integrating cell on chip—Novel waveguide platform employing ultra-long optical paths

NASA Astrophysics Data System (ADS)

Fohrmann, Lena Simone; Sommer, Gerrit; Pitruzzello, Giampaolo; Krauss, Thomas F.; Petrov, Alexander Yu.; Eich, Manfred

2017-09-01

Optical waveguides are the most fundamental building blocks of integrated optical circuits. They are extremely well understood, yet there is still room for surprises. Here, we introduce a novel 2D waveguide platform which affords a strong interaction of the evanescent tail of a guided optical wave with an external medium while only employing a very small geometrical footprint. The key feature of the platform is its ability to integrate the ultra-long path lengths by combining low propagation losses in a silicon slab with multiple reflections of the guided wave from photonic crystal (PhC) mirrors. With a reflectivity of 99.1% of our tailored PhC-mirrors, we achieve interaction paths of 25 cm within an area of less than 10 mm2. This corresponds to 0.17 dB/cm effective propagation which is much lower than the state-of-the-art loss of approximately 1 dB/cm of single mode silicon channel waveguides. In contrast to conventional waveguides, our 2D-approach leads to a decay of the guided wave power only inversely proportional to the optical path length. This entirely different characteristic is the major advantage of the 2D integrating cell waveguide platform over the conventional channel waveguide concepts that obey the Beer-Lambert law.

Multi scale modeling of ignition and combustion of micro and nano aluminum particles

NASA Astrophysics Data System (ADS)

Puri, Puneesh

With renewed interest in nano scale energetic materials like aluminum, many fundamental issues concerning the ignition and combustion characteristics at nano scales, remain to be clarified. The overall aim of the current study is the establishment of a unified theory accommodating the various processes and mechanisms involved in the combustion and ignition of aluminum particles at micro and nano scales. A comprehensive review on the ignition and combustion of aluminum particles at multi scales was first performed identifying various processes and mechanisms involved. Research focus was also placed on the establishment of a Molecular Dynamics (MD) simulation tool to investigate the characteristics of nano-particulate aluminum through three major studies. The general computational framework involved parallelized preprocessing, post-processing and main code with capability to simulate different ensembles using appropriate algorithms. Size dependence of melting temperature of pure aluminum particles was investigated in the first study. Phenomena like dynamic coexistence of solid and liquid phase and effect of surface charges on melting were explored. The second study involved the study of effect of defects in the form of voids on melting of bulk and particulate phase aluminum. The third MD study was used to analyze the thermo-mechanical behavior of nano-sized aluminum particles with total diameter of 5-10 nm and oxide thickness of 1-2.5 nm. The ensuing solid-solid and solid-liquid phase changes in the core and shell, stresses developed within the shell, and the diffusion of aluminum cations in the oxide layer, were explored in depth for amorphous and crystalline oxide layers. In the limiting case, the condition for pyrophoricity/explosivity of nano-particulate aluminum was analyzed and modified. The size dependence of thermodynamic properties at nano scales were considered and incorporated into the existing theories developed for micro and larger scales. Finally, a

Using refraction in thick glass plates for optical path length modulation in low coherence interferometry.

PubMed

Kröger, Niklas; Schlobohm, Jochen; Pösch, Andreas; Reithmeier, Eduard

2017-09-01

In Michelson interferometer setups the standard way to generate different optical path lengths between a measurement arm and a reference arm relies on expensive high precision linear stages such as piezo actuators. We present an alternative approach based on the refraction of light at optical interfaces using a cheap stepper motor with high gearing ratio to control the rotation of a glass plate. The beam path is examined and a relation between angle of rotation and change in optical path length is devised. As verification, an experimental setup is presented, and reconstruction results from a measurement standard are shown. The reconstructed step height from this setup lies within 1.25% of the expected value.

Trapping and assembling of particles and live cells on large-scale random gold nano-island substrates

PubMed Central

Kang, Zhiwen; Chen, Jiajie; Wu, Shu-Yuen; Chen, Kun; Kong, Siu-Kai; Yong, Ken-Tye; Ho, Ho-Pui

2015-01-01

We experimentally demonstrated the use of random plasmonic nano-islands for optical trapping and assembling of particles and live cells into highly organized pattern with low power density. The observed trapping effect is attributed to the net contribution due to near-field optical trapping force and long-range thermophoretic force, which overcomes the axial convective drag force, while the lateral convection pushes the target objects into the trapping zone. Our work provides a simple platform for on-chip optical manipulation of nano- and micro-sized objects, and may find applications in physical and life sciences. PMID:25928045

High efficient optical remote sensing images acquisition for nano-satellite-framework

NASA Astrophysics Data System (ADS)

Li, Feng; Xin, Lei; Liu, Yang; Fu, Jie; Liu, Yuhong; Guo, Yi

2017-09-01

It is more difficult and challenging to implement Nano-satellite (NanoSat) based optical Earth observation missions than conventional satellites because of the limitation of volume, weight and power consumption. In general, an image compression unit is a necessary onboard module to save data transmission bandwidth and disk space. The image compression unit can get rid of redundant information of those captured images. In this paper, a new image acquisition framework is proposed for NanoSat based optical Earth observation applications. The entire process of image acquisition and compression unit can be integrated in the photo detector array chip, that is, the output data of the chip is already compressed. That is to say, extra image compression unit is no longer needed; therefore, the power, volume, and weight of the common onboard image compression units consumed can be largely saved. The advantages of the proposed framework are: the image acquisition and image compression are combined into a single step; it can be easily built in CMOS architecture; quick view can be provided without reconstruction in the framework; Given a certain compression ratio, the reconstructed image quality is much better than those CS based methods. The framework holds promise to be widely used in the future.

Interconnecting wearable devices with nano-biosensing implants through optical wireless communications

NASA Astrophysics Data System (ADS)

Johari, Pedram; Pandey, Honey; Jornet, Josep M.

2018-02-01

Major advancements in the fields of electronics, photonics and wireless communication have enabled the development of compact wearable devices, with applications in diverse domains such as fitness, wellness and medicine. In parallel, nanotechnology is enabling the development of miniature sensors that can detect events at the nanoscale with unprecedented accuracy. On this matter, in vivo implantable Surface Plasmon Resonance (SPR) nanosensors have been proposed to analyze circulating biomarkers in body fluids for the early diagnosis of a myriad of diseases, ranging from cardiovascular disorders to different types of cancer. In light of these results, in this paper, an architecture is proposed to bridge the gap between these two apparently disjoint paradigms, namely, the commercial wearable devices and the advanced nano-biosensing technologies. More specifically, this paper thoroughly assesses the feasibility of the wireless optical intercommunications of an SPR-based nanoplasmonic biochip -implanted subcutaneously in the wrist-, with a nanophotonic wearable smart band which is integrated by an array of nano-lasers and photon-detectors for distributed excitation and measurement of the nanoplasmonic biochip. This is done through a link budget analysis which captures the peculiarities of the intra-body optical channel at (sub) cellular level, the strength of the SPR nanosensor reflection, as well as the capabilities of the nanolasers (emission power, spectrum) and the nano photon-detectors (sensitivity and noise equivalent power). The proposed analysis guides the development of practical communication designs between the wearable devices and nano-biosensing implants, which paves the way through early-stage diagnosis of severe diseases.

Advances in lasers and optical micro-nano-systems

NASA Astrophysics Data System (ADS)

Laurell, F.; Fazio, E.

2010-09-01

Lasers represent a well consolidated technology: nevertheless, research in this field remains very active and productive, in both basic and applied directions. At the moment significant attention is given to those sources that bring together high power and compactness. Such high power lasers find important applications for material treatments and such applications are presented by Ehsani et al and Saiedeh Saghafi et al, in the treatment of dielectric thin films (Alteration of optical and morphological properties of polycarbonate illuminated by visible/IR laser beams) or of biological tissues like pistachio seeds (Investigating the effects of laser beams (532 and 660 nm) in annihilation of pistachio mould fungus using spectrophotometry analysis). In particular the latter paper show how laser sources can find very important applications in new domains, preserving goods and food without the need for preservatives or pesticides by simply sterilizing them using light. Optical Micro and Nano Systems presents a new domain for exploration. In this framework this special issue is very attractive, because it assembles papers reporting new results in three directions: new techniques for monitoring integrated micro- and nano-systems, new integrated systems and novel high performance metamaterial configurations. Integrated micro-components can be monitored and controlled using reflectance measurements as presented by Piombini et al (Toward the reflectance measurement of micro components). Speckle formation during laser beam reflection can also be a very sophisticated tool for detecting ultra-precise displacements, as presented by Filter et al (High resolution displacement detection with speckles : accuracy limits in linear displacement speckle metrology). Three dimensional integrated optical structures is indeed a big challenge and a peculiarity of photonics, they can be formed through traditional holography or using more sophisticated and novel ! technologies. Thus, special

Nano-Fabrication Methods for Micro-Miniature Optical Thermometers Suited to High Temperatures and Harsh Environments

NASA Astrophysics Data System (ADS)

DePew, K. A.; Ma, C.; Schiffbauer, J. D.; Wang, J.; Dong, B.; Lally, E.; Wang, A.

2012-12-01

The Center for Photonics Technology (CPT) at Virginia Tech is engaged in cutting edge research of fiber optic sensing technologies. One current research area is the design of fiber optic temperature sensors for harsh environments. Fiber optic temperature sensing offers significant advantages over electronic sensing in terms of size and insensitivity to harsh environmental conditions and electromagnetic interference. In the field, fiber optic thermometers have been used in recent snow cover studies as well as fluvial temperature profiling projects. The extended capabilities of CPT optical sensors open further possibilities for application in additional geologic realms requiring high temperature sensing in corrosive environments. Significant strides have been made in developing single-crystal sapphire based fiber optic sensing elements for high temperature environments which are otherwise difficult to instrument. Utilization of strain insensitive designs and optical sapphire materials allow for thermometers capable of operation above 1500°C with reduced sensitivity to chemical corrosion and mechanical interference. Current efforts in fabrication techniques are reducing the footprint of temperature sensors below the millimeter scale while maintaining high resolution and operating range. The FEI Helios 600 NanoLab workstation at the Virginia Tech Institute for Critical Technologies and Applied Science has been employed, providing the capabilities necessary to reduce the footprint of sensing elements to the dimensions of standard optical communication fiber using a Ga+ focused ion beam (FIB). The capability of semi-distributed multi-point sensing can also be accomplished at this scale using similar FIB milling techniques. The fiber optic thermometer designs resulting from these methods are compact, lightweight, and able to provide remote sensing without need for electrical power at the measurement point. These traits make them an ideal sensing platform for laboratory

Controlled crystallization and granulation of nano-scale β-Ni(OH) 2 cathode materials for high power Ni-MH batteries

NASA Astrophysics Data System (ADS)

He, Xiangming; Li, Jianjun; Cheng, Hongwei; Jiang, Changyin; Wan, Chunrong

A novel synthesis of controlled crystallization and granulation was attempted to prepare nano-scale β-Ni(OH) 2 cathode materials for high power Ni-MH batteries. Nano-scale β-Ni(OH) 2 and Co(OH) 2 with a diameter of 20 nm were prepared by controlled crystallization, mixed by ball milling, and granulated to form about 5 μm spherical grains by spray drying granulation. Both the addition of nano-scale Co(OH) 2 and granulation significantly enhanced electrochemical performance of nano-scale Ni(OH) 2. The XRD and TEM analysis shown that there were a large amount of defects among the crystal lattice of as-prepared nano-scale Ni(OH) 2, and the DTA-TG analysis shown that it had both lower decomposition temperature and higher decomposition reaction rate, indicating less thermal stability, as compared with conventional micro-scale Ni(OH) 2, and indicating that it had higher electrochemical performance. The granulated grains of nano-scale Ni(OH) 2 mixed with nano-scale Co(OH) 2 at Co/Ni = 1/20 presented the highest specific capacity reaching its theoretical value of 289 mAh g -1 at 1 C, and also exhibited much improved electrochemical performance at high discharge capacity rate up to 10 C. The granulated grains of nano-scale β-Ni(OH) 2 mixed with nano-scale Co(OH) 2 is a promising cathode active material for high power Ni-MH batteries.

CW laser damage testing of RAR nano-textured fused silica and YAG

NASA Astrophysics Data System (ADS)

MacLeod, Bruce D.; Hobbs, Douglas S.; Manni, Anthony D.; Sabatino, Ernest; Bernot, David M.; DeFrances, Sage; Randi, Joseph A.; Thomas, Jeffrey

2017-11-01

A study of the continuous wave (CW) laser induced damage threshold (LiDT) of fused silica and yttrium aluminum garnet (YAG) optics was conducted to further illustrate the enhanced survivability within high power laser systems of an anti-reflection (AR) treatment consisting of randomly distributed surface relief nanostructures (RAR). A series of three CW LiDT tests using the 1070nm wavelength, 16 KW fiber laser test bed at Penn State Electro-Optic Center (PSEOC) were designed and completed, with improvements in the testing protocol, areal coverage, and maximum exposure intensities implemented between test cycles. Initial results for accumulated power, stationary site exposures of RAR nano-textured optics showed no damage and low surface temperatures similar to the control optics with no AR treatment. In contrast, optics with thin-film AR coatings showed high surface temperatures consistent with absorption by the film layers. Surface discriminating absorption measurements made using the Photothermal Common-path Interferometry (PCI) method, showed zero added surface absorption for the RAR nanotextured optics, and absorption levels in the 2-5 part per million range for thin-film AR coated optics. In addition, the surface absorption of thin-film AR coatings was also found to have localized absorption spikes that are likely pre-cursors for damage. Subsequent CW LiDT testing protocol included raster scanning an increased intensity focused beam over the test optic surface where it was found that thin-film AR coated optics damaged at intensities in the 2 to 5 MW/cm2 range with surface temperatures over 250C during the long-duration exposures. Significantly, none of the 10 RAR nano-textured fused silica optics tested could be damaged up to the maximum system intensity of 15.5 MW/cm2, and surface temperatures remained low. YAG optics tested during the final cycle exhibited a similar result with RAR nano-textured surfaces surviving intensities over 3 times higher than thin

Nano-scaled top-down of bismuth chalcogenides based on electrochemical lithium intercalation

NASA Astrophysics Data System (ADS)

Chen, Jikun; Zhu, Yingjie; Chen, Nuofu; Liu, Xinling; Sun, Zhengliang; Huang, Zhenghong; Kang, Feiyu; Gao, Qiuming; Jiang, Jun; Chen, Lidong

2011-12-01

A two-step method has been used to fabricate nano-particles of layer-structured bismuth chalcogenide compounds, including Bi2Te3, Bi2Se3, and Bi2Se0.3Te2.7, through a nano-scaled top-down route. In the first step, lithium (Li) atoms are intercalated between the van der Waals bonded quintuple layers of bismuth chalcogenide compounds by controllable electrochemical process inside self-designed lithium ion batteries. And in the second step, the Li intercalated bismuth chalcogenides are subsequently exposed to ethanol, in which process the intercalated Li atoms would explode like atom-scaled bombs to exfoliate original microscaled powder into nano-scaled particles with size around 10 nm. The influence of lithium intercalation speed and amount to three types of bismuth chalcogenide compounds are compared and the optimized intercalation conditions are explored. As to maintain the phase purity of the final nano-particle product, the intercalation lithium amount should be well controlled in Se contained bismuth chalcogenide compounds. Besides, compared with binary bismuth chalcogenide compound, lower lithium intercalation speed should be applied in ternary bismuth chalcogenide compound.

Production of ultra-thin nano-scaled graphene platelets from meso-carbon micro-beads

DOEpatents

Zhamu, Aruna; Guo, Jiusheng; Jang, Bor Z

2014-11-11

A method of producing nano-scaled graphene platelets (NGPs) having an average thickness no greater than 50 nm, typically less than 2 nm, and, in many cases, no greater than 1 nm. The method comprises (a) intercalating a supply of meso-carbon microbeads (MCMBs) to produce intercalated MCMBs; and (b) exfoliating the intercalated MCMBs at a temperature and a pressure for a sufficient period of time to produce the desired NGPs. Optionally, the exfoliated product may be subjected to a mechanical shearing treatment, such as air milling, air jet milling, ball milling, pressurized fluid milling, rotating-blade grinding, or ultrasonicating. The NGPs are excellent reinforcement fillers for a range of matrix materials to produce nanocomposites. Nano-scaled graphene platelets are much lower-cost alternatives to carbon nano-tubes or carbon nano-fibers.

Characterization of Nano-scale Aluminum Oxide Transport through Porous Media

NASA Astrophysics Data System (ADS)

Norwood, S.; Reynolds, M.; Miao, Z.; Brusseau, M. L.; Johnson, G. R.

2011-12-01

Colloidal material (including that in the nanoparticle size range) is naturally present in most subsurface environments. Mobilization of these colloidal materials via particle disaggregation may occur through abrupt changes in flow rate and/or via chemical perturbations, such as rapid changes in ionic strength or solution pH. While concentrations of natural colloidal materials in the subsurface are typically small, those concentrations may be greatly increased at contaminated sites such as following the application of metal oxides for groundwater remediation efforts. Additionally, while land application of biosolids has become common practice in the United States as an alternative to industrial fertilizers, biosolids have been shown to contain a significant fraction of organic and inorganic nano-scale colloidal materials such as oxides of iron, titanium, and aluminum. Given their reactivity and small size, there are many questions concerning the potential migration of nano-scale colloidal materials through the soil column and their potential participation in the facilitated transport of contaminants, such as heavy metals and emerging pollutants. The purpose of this study was to investigate the transport behavior of aluminum oxide (Al2O3) nanoparticles through porous media. The impacts of pH, ionic strength, pore-water velocity (i.e., residence time), and aqueous-phase concentration on transport was investigated. All experiments were conducted with large injection pulses to fully characterize the impact of long-term retention and transport behavior relevant for natural systems wherein multiple retention processes may be operative. The results indicate that the observed nonideal transport behavior of the nano-scale colloids is influenced by multiple retention mechanisms/processes. Given the ubiquitous nature of these nano-scale colloids in the environment, a clear understanding of their transport and fate is necessary in further resolving the potential for

Optical path difference microscopy with a Shack-Hartmann wavefront sensor.

PubMed

Gong, Hai; Agbana, Temitope E; Pozzi, Paolo; Soloviev, Oleg; Verhaegen, Michel; Vdovin, Gleb

2017-06-01

In this Letter, we show that a Shack-Hartmann wavefront sensor can be used for the quantitative measurement of the specimen optical path difference (OPD) in an ordinary incoherent optical microscope, if the spatial coherence of the illumination light in the plane of the specimen is larger than the microscope resolution. To satisfy this condition, the illumination numerical aperture should be smaller than the numerical aperture of the imaging lens. This principle has been successfully applied to build a high-resolution reference-free instrument for the characterization of the OPD of micro-optical components and microscopic biological samples.

Prevention of arterial graft spasm in rats using a vasodilator-eluting biodegradable nano-scaled fibre†

PubMed Central

Yagami, Kei; Yamawaki-Ogata, Aika; Satake, Makoto; Kaneko, Hiroaki; Oshima, Hideki; Usui, Akihiko; Ueda, Yuichi; Narita, Yuji

2013-01-01

OBJECTIVES Arterial graft spasm occasionally causes circulatory collapse immediately following coronary artery bypass graft. The aim of this study is to evaluate the efficacy of our developed materials, which were composed of milrinone (phosphodiesterase III inhibitor) or diltiazem (calcium-channel blocker), with nano-scaled fibre made of biodegradable polymer to prevent arterial spasm. METHODS Milrinone- or diltiazem-releasing biodegradable nano-scaled fibres were fabricated by an electrospinning procedure. In vivo milrinone- or diltiazem-releasing tests were performed to confirm the sustained release of the drugs. An in vivo arterial spasm model was established by subcutaneous injection of noradrenalin around the rat femoral artery. Rats were randomly divided into four groups as follows: those that received 5 mg of milrinone-releasing biodegradable nano-scaled fibre (group M, n = 14); 5 mg of diltiazem-releasing biodegradable nano-scaled fibre (group D, n = 12); or those that received fibre without drugs (as a control; group C, n = 14) implanted into the rat femoral artery. In the fourth group, sham operation was performed (group S, n = 10). One day after the implantation, noradrenalin was injected in all groups. The femoral arterial blood flow was measured continuously before and after noradrenalin injection. The maximum blood flow before noradrenalin injection and minimum blood flow after noradrenalin injection were measured. RESULTS In vivo drug-releasing test revealed that milrinone-releasing biodegradable nano-scaled fibre released 78% of milrinone and diltiazem-releasing biodegradable nano-scaled fibre released 50% diltiazem on the first day. The ratios of rat femoral artery blood flow after/before noradrenalin injection in groups M (0.74 ± 0.16) and D (0.72 ± 0.05) were significantly higher than those of groups C (0.54 ± 0.09) and S (0.55 ± 0.16) (P < 0.05). CONCLUSION Noradrenalin-induced rat femoral artery spasm was inhibited by the implantation of

Optical path design of phase contrast imaging on HL-2A tokamak

NASA Astrophysics Data System (ADS)

Qiyun, CHENG; Yi, YU; Shaobo, GONG; Min, XU; Tao, LAN; Wei, JIANG; Boda, YUAN; Yifan, WU; Lin, NIE; Rui, KE; Ting, LONG; Dong, GUO; Minyou, YE; Xuru, DUAN

2017-12-01

A phase contrast imaging (PCI) diagnostic has recently been developed on HL-2A tokamak. It can diagnose plasma density fluctuations with maximum wave number of 15 cm-1 and wave number resolution of 2 cm-1. The time resolution reaches 2 μs. A 10.6 μm CO2 laser is expanded to a beam with a diameter of 30 mm and injected into the plasma as an incident beam, injecting into plasma. The emerging scattered and unscattered beams are contrasted by a phase plate. The ideas of optical path design are presented in this paper, together with the parameters of the main optical components. The whole optical path of PCI is not only carefully designed, but also constructed on HL-2A. First calibration results show the ability of this system to catch plasma turbulence in a wide frequency domain.

Cloud Optical Depths and Liquid Water Paths at the NSA CART

DOE Office of Scientific and Technical Information (OSTI.GOV)

Doran, J C.; Barnard, James C.; Zhong, Shiyuan

2000-03-14

Cloud optical depths have been measured using multifilter rotating shadowband radiometers (MFRSRs) at Barrow and Atqasuk, and liquid water paths have been measured at Barrow using a microwave radiometer (MWR) during the warm season (June-September) in 1999. Comparisons have been made between these quantities and the corresponding ones determined from the ECMWF GCM. Hour-by-hour comparisons of cloud optical depths show considerable scatter. The scatter is reduced, but is still substantial, when the averaging period is increased to ''daily'' averages, i.e., the time period each day over which the MFRSR can make measurements. This period varied between 18 hours in Junemore » and 6 hours in September. Preliminary results indicate that, for measured cloud optical depths less than approximately 25, the ECMWF has a low bias in its predictions, consistent with a low bias in predicted liquid water path. Based on a more limited set of data, the optical depths at Atqasuk were found to be generally lower than those at Barrow, a trend at least qualitatively captured by the ECMWF model. Analyses to identify the cause of the biases and the considerable scatter in the predictions are continuing.« less

Nicholas Metropolis Award for Outstanding Doctoral Thesis Work in Computational Physics Talk: Understanding Nano-scale Electronic Systems via Large-scale Computation

NASA Astrophysics Data System (ADS)

Cao, Chao

2009-03-01

Nano-scale physical phenomena and processes, especially those in electronics, have drawn great attention in the past decade. Experiments have shown that electronic and transport properties of functionalized carbon nanotubes are sensitive to adsorption of gas molecules such as H2, NO2, and NH3. Similar measurements have also been performed to study adsorption of proteins on other semiconductor nano-wires. These experiments suggest that nano-scale systems can be useful for making future chemical and biological sensors. Aiming to understand the physical mechanisms underlying and governing property changes at nano-scale, we start off by investigating, via first-principles method, the electronic structure of Pd-CNT before and after hydrogen adsorption, and continue with coherent electronic transport using non-equilibrium Green’s function techniques combined with density functional theory. Once our results are fully analyzed they can be used to interpret and understand experimental data, with a few difficult issues to be addressed. Finally, we discuss a newly developed multi-scale computing architecture, OPAL, that coordinates simultaneous execution of multiple codes. Inspired by the capabilities of this computing framework, we present a scenario of future modeling and simulation of multi-scale, multi-physical processes.

Common path endoscopic probes for optical coherence tomography (Conference Presentation)

NASA Astrophysics Data System (ADS)

Singh, Kanwarpal; Gardecki, Joseph A.; Tearney, Guillermo J.

2017-02-01

Background: Dispersion imbalance and polarization mismatch between the reference and sample arm signals can lead to image quality degradation in optical coherence tomography (OCT). One approach to reduce these image artifacts is to employ a common-path geometry in fiber-based probes. In this work, we report an 800 um diameter all-fiber common-path monolithic probe for coronary artery imaging where the reference signal is generated using an inline fiber partial reflector. Methods: Our common-path probe was designed for swept-source based Fourier domain OCT at 1310 nm wavelength. A face of a coreless fiber was coated with gold and spliced to a standard SMF-28 single mode fiber creating an inline partial reflector, which acted as a reference surface. The other face of the coreless fiber was shaped into a ball lens for focusing. The optical elements were assembled within a 560 µm diameter drive shaft, which was attached to a rotary junction. The drive shaft was placed inside a transparent sheath having an outer diameter of 800 µm. Results: With a source input power of 30mW, the inline common-path probe achieved a sensitivity of 104 dB. Images of human finger skin showed the characteristic layers of skin as well as features such as sweat ducts. Images of coronary arteries ex vivo obtained with this probe enabled visualization of the characteristic architectural morphology of the normal artery wall and known features of atherosclerotic plaque. Conclusion: In this work, we have demonstrated a common path OCT probe for cardiovascular imaging. The probe is easy to fabricate, will reduce system complexity and overall cost. We believe that this design will be helpful in endoscopic applications that require high resolution and a compact form factor.

Formation and metrology of dual scale nano-morphology on SF(6) plasma etched silicon surfaces.

PubMed

Boulousis, G; Constantoudis, V; Kokkoris, G; Gogolides, E

2008-06-25

Surface roughness and nano-morphology in SF(6) plasma etched silicon substrates are investigated in a helicon type plasma reactor as a function of etching time and process parameters. The plasma etched surfaces are analyzed by atomic force microscopy. It is found that dual scale nano-roughness is formatted on the silicon surface comprising an underlying nano-roughness and superimposed nano-mounds. Detailed metrological quantification is proposed for the characterization of dual scale surface morphology. As etching proceeds, the mounds become higher, fewer and wider, and the underlying nano-roughness also increases. Increase in wafer temperature leads to smoother surfaces with lower, fewer and wider nano-mounds. A mechanism based on the deposition of etch inhibiting particles during the etching process is proposed for the explanation of the experimental behavior. In addition, appropriately designed experiments are conducted, and they confirm the presence of this mechanism.

MODIFIED PATH METHODOLOGY FOR OBTAINING INTERVAL-SCALED POSTURAL ASSESSMENTS OF FARMWORKERS.

PubMed

Garrison, Emma B; Dropkin, Jonathan; Russell, Rebecca; Jenkins, Paul

2018-01-29

Agricultural workers perform tasks that frequently require awkward and extreme postures that are associated with musculoskeletal disorders (MSDs). The PATH (Posture, Activity, Tools, Handling) system currently provides a sound methodology for quantifying workers' exposure to these awkward postures on an ordinal scale of measurement, which places restrictions on the choice of analytic methods. This study reports a modification of the PATH methodology that instead captures these postures as degrees of flexion, an interval-scaled measurement. Rather than making live observations in the field, as in PATH, the postural assessments were performed on photographs using ImageJ photo analysis software. Capturing the postures in photographs permitted more careful measurement of the degrees of flexion. The current PATH methodology requires that the observer in the field be trained in the use of PATH, whereas the single photographer used in this modification requires only sufficient training to maintain the proper camera angle. Ultimately, these interval-scale measurements could be combined with other quantitative measures, such as those produced by electromyograms (EMGs), to provide more sophisticated estimates of future risk for MSDs. Further, these data can provide a baseline from which the effects of interventions designed to reduce hazardous postures can be calculated with greater precision. Copyright© by the American Society of Agricultural Engineers.

Effect of Particle Size and Impact Velocity on Collision Behaviors Between Nano-Scale TiN Particles: MD Simulation.

PubMed

Yao, Hai-Long; Hu, Xiao-Zhen; Yang, Guan-Jun

2018-06-01

Inter-particle bonding formation which determines qualities of nano-scale ceramic coatings is influenced by particle collision behaviors during high velocity collision processes. In this study, collision behaviors between nano-scale TiN particles with different diameters were illuminated by using Molecular Dynamics simulation through controlling impact velocities. Results show that nano-scale TiN particles exhibit three states depending on particle sizes and impact velocities, i.e., bonding, bonding with localized fracturing, and rebounding. These TiN particles states are summarized into a parameter selection map providing an overview of the conditions in terms of particle sizes and velocities. Microstructure results show that localized atoms displacement and partial fracture around the impact region are main reasons for bonding formation of nano-scale ceramic particles, which shows differences from conventional particles refining and amorphization. A relationship between the adhesion energy and the rebound energy is established to understand bonding formation mechanism for nano-scale TiN particle collision. Results show that the energy relationship is depended on the particle sizes and impact velocities, and nano-scale ceramic particles can be bonded together as the adhesion energy being higher than the rebound energy.

A Study on the Applications of Quantum Optical Coherence to Nano-Optics

NASA Astrophysics Data System (ADS)

Hakami, Jabir Wali

Optically controlled dipole-dipole interaction at submicrometers and subwavelength scales leads to many interesting phenomenon and remarkable potential applications in quantum optics, condensed matter physics, and today's micro-devices. In this dissertation, we study the applications of quantum optical coherence to nano-optics in the following systems and aspects. On the one hand, chiral metamaterials has been previously reported as excellent candidates to realize both attractive and repulsive Casimir forces, where the existence of a repulsive Casimir force depends upon the strength of the chirality. On the other hand, nanoscale integration of metal nanoparticles and semiconductors is particularly interesting because the strengths of both materials are combined in such a hybrid system. In the first part of this work, we proposed a technical scheme to coherently control of the Casimir interaction energy with two identical chirality mediums. We took explicit caution regarding the requirements of passivity and causal response of the materials, since these requirements are essential for the application of the Lifshitz formula. The rare-earth metals' atomic species, for instance, dysprosium, is proposed as an applicable medium for the forthcoming studies of possible experimental implementation of our technique. Secondly, we fully investigated the coherent control of the quantum optical properties of spontaneous emission spectra of a semiconductor quantum dot coupled to a metallic nanoparticle. The properties of the spontaneous emission spectra of such a system are studied in detail with and without involving the coherent field. The Rabi splitting effect in the spectrum emitted by the quantum dot under particular conditions is predicted for different sizes of the metal nanoparticles. We show that the spontaneous emission spectra of the transition coupled to surface plasmons may be further modified by adjusting the external coherent control on the adjacent transitions. In

Progress of pancreatitis disease biomarker alpha amylase enzyme by new nano optical sensor.

PubMed

Attia, M S; Al-Radadi, Najlaa S

2016-12-15

A new nano optical sensor binuclear Pd-(2-aminothiazole) (urea), Pd(atz,ur) complex was prepared and characterized for the assessment of the activity of alpha amylase enzyme in urine and serum samples for early diagnosis of Pancreatitis disease. The assessment of alpha amylase activity is carried out by the quenching of the luminescence intensity of the nano optical sensor binuclear Pd(atz,ur) complex at 457nm by the 2-chloro-4-nitrophenol (2-CNP) which produced from the reaction of the enzyme with 2-chloro-4-nitrophenyl-α-d-maltotrioside (CNPG3) substrate. The remarkable quenching of the luminescence intensity at 457nm of nano Pd(atz,ur) doped in sol-gel matrix by various concentrations of the 2-CNP was successfully used as an optical sensor for the assessment of α-amylase activity. The calibration plot was achieved over the concentration range 8.5×10(-6) to 1.9×10(-9)molL(-1) 2-CNP with a correlation coefficient of (0.999) and a detection limit of (7.4×10(-10)molL(-1)). The method was used satisfactorily for the assessment of the α-amylase activity over activity range (3-321U/L) in different urine and serum samples of pancreatitis patients. The assessment of the alpha amylase biomarker by the proposed method increases its sensitivity (96.88%) and specificity (94.41%) for early diagnosis of pancreatitis diseases. Copyright © 2016 Elsevier B.V. All rights reserved.

The Neurologic Assessment in Neuro-Oncology (NANO) Scale as an Assessment Tool for Survival in Patients With Primary Glioblastoma.

PubMed

Ung, Timothy H; Ney, Douglas E; Damek, Denise; Rusthoven, Chad G; Youssef, A Samy; Lillehei, Kevin O; Ormond, D Ryan

2018-03-30

The Neurologic Assessment in Neuro-Oncology (NANO) scale is a standardized objective metric designed to measure neurological function in neuro-oncology. Current neuroradiological evaluation guidelines fail to use specific clinical criteria for progression. To determine if the NANO scale was a reliable assessment tool in glioblastoma (GBM) patients and whether it correlated to survival. Our group performed a retrospective review of all patients with newly diagnosed GBM from January 1, 2010, through December 31, 2012, at our institution. We applied the NANO scale, Karnofsky performance score (KPS), Eastern Cooperative Oncology Group (ECOG) scale, Macdonald criteria, and the Response Assessment in Neuro-Oncology (RANO) criteria to patients at the time of diagnosis as well as at 3, 6, and 12 mo. Initial NANO score was correlated with overall survival at time of presentation. NANO progression was correlated with decreased survival in patients at 6 and 12 mo. A decrease in KPS was associated with survival at 3 and 6 mo, an increase in ECOG score was associated only at 3 mo, and radiological evaluation (RANO and Macdonald) was correlated at 3 and 6 mo. Only the NANO scale was associated with patient survival at 1 yr. NANO progression was the only metric that was linked to decreased overall survival when compared to RANO and Macdonald at 6 and 12 mo. The NANO scale is specific to neuro-oncology and can be used to assess patients with glioma. This retrospective analysis demonstrates the usefulness of the NANO scale in glioblastoma.

Simulation of the fixed optical path difference of near infrared wind imaging interferometer

NASA Astrophysics Data System (ADS)

Rong, Piao; Zhang, Chunmin; Yan, Tingyu; Liu, Dongdong; Li, Yanfen

2017-02-01

As an important part of the earth, atmosphere plays a vital role in filtering the solar radiation, adjusting the temperature and organizing the water circulation and keeping human survival. The passive atmospheric wind measurement is based on the imaging interferometer technology and Doppler effect of electromagnetic wave. By using the wind imaging interferometer to get four interferograms of airglow emission lines, the atmospheric wind velocity, temperature, pressure and emission rate can be derived. Exploring the multi-functional and integrated innovation of detecting wind temperature, wind velocity and trace gas has become a research focus in the field. In the present paper, the impact factors of the fixed optical path difference(OPD) of near infrared wind imaging interferometer(NIWII) are analyzed and the optimum value of the fixed optical path difference is simulated, yielding the optimal results of the fixed optical path difference is 20 cm in near infrared wave band (the O2(a1Δg) airglow emission at 1.27 microns). This study aims at providing theoretical basis and technical support for the detection of stratosphere near infrared wind field and giving guidance for the design and development of near infrared wind imaging interferometer.

Nano-Scale Spatial Assessment of Calcium Distribution in Coccolithophores Using Synchrotron-Based Nano-CT and STXM-NEXAFS

PubMed Central

Sun, Shiyong; Yao, Yanchen; Zou, Xiang; Fan, Shenglan; Zhou, Qing; Dai, Qunwei; Dong, Faqin; Liu, Mingxue; Nie, Xiaoqin; Tan, Daoyong; Li, Shuai

2014-01-01

Calcified coccolithophores generate calcium carbonate scales around their cell surface. In light of predicted climate change and the global carbon cycle, the biomineralization ability of coccoliths has received growing interest. However, the underlying biomineralization mechanism is not yet well understood; the lack of non-invasive characterizing tools to obtain molecular level information involving biogenic processes and biomineral components remain significant challenges. In the present study, synchrotron-based Nano-computed Tomography (Nano-CT) and Scanning Transmission X-ray Microscopy-Near-edge X-ray Absorption Fine Structure Spectromicroscopy (STXM-NEXAFS) techniques were employed to identify Ca spatial distribution and investigate the compositional chemistry and distinctive features of the association between biomacromolecules and mineral components of calcite present in coccoliths. The Nano-CT results show that the coccolith scale vesicle is similar as a continuous single channel. The mature coccoliths were intracellularly distributed and immediately ejected and located at the exterior surface to form a coccoshpere. The NEXAFS spectromicroscopy results of the Ca L edge clearly demonstrate the existence of two levels of gradients spatially, indicating two distinctive forms of Ca in coccoliths: a crystalline-poor layer surrounded by a relatively crystalline-rich layer. The results show that Sr is absorbed by the coccoliths and that Sr/Ca substitution is rather homogeneous within the coccoliths. Our findings indicate that synchrotron-based STXM-NEXAFS and Nano-CT are excellent tools for the study of biominerals and provide information to clarify biomineralization mechanism. PMID:25530614

Nano-scale measurement of biomolecules by optical microscopy and semiconductor nanoparticles

PubMed Central

Ichimura, Taro; Jin, Takashi; Fujita, Hideaki; Higuchi, Hideo; Watanabe, Tomonobu M.

2014-01-01

Over the past decade, great developments in optical microscopy have made this technology increasingly compatible with biological studies. Fluorescence microscopy has especially contributed to investigating the dynamic behaviors of live specimens and can now resolve objects with nanometer precision and resolution due to super-resolution imaging. Additionally, single particle tracking provides information on the dynamics of individual proteins at the nanometer scale both in vitro and in cells. Complementing advances in microscopy technologies has been the development of fluorescent probes. The quantum dot, a semi-conductor fluorescent nanoparticle, is particularly suitable for single particle tracking and super-resolution imaging. This article overviews the principles of single particle tracking and super resolution along with describing their application to the nanometer measurement/observation of biological systems when combined with quantum dot technologies. PMID:25120488

Wavelength-scale photonic-crystal laser formed by electron-beam-induced nano-block deposition.

PubMed

Seo, Min-Kyo; Kang, Ju-Hyung; Kim, Myung-Ki; Ahn, Byeong-Hyeon; Kim, Ju-Young; Jeong, Kwang-Yong; Park, Hong-Gyu; Lee, Yong-Hee

2009-04-13

A wavelength-scale cavity is generated by printing a carbonaceous nano-block on a photonic-crystal waveguide. The nanometer-size carbonaceous block is grown at a pre-determined region by the electron-beam-induced deposition method. The wavelength-scale photonic-crystal cavity operates as a single mode laser, near 1550 nm with threshold of approximately 100 microW at room temperature. Finite-difference time-domain computations show that a high-quality-factor cavity mode is defined around the nano-block with resonant wavelength slightly longer than the dispersion-edge of the photonic-crystal waveguide. Measured near-field images exhibit photon distribution well-localized in the proximity of the printed nano-block. Linearly-polarized emission along the vertical direction is also observed.

Fabrication of nano-scale Cu bond pads with seal design in 3D integration applications.

PubMed

Chen, K N; Tsang, C K; Wu, W W; Lee, S H; Lu, J Q

2011-04-01

A method to fabricate nano-scale Cu bond pads for improving bonding quality in 3D integration applications is reported. The effect of Cu bonding quality on inter-level via structural reliability for 3D integration applications is investigated. We developed a Cu nano-scale-height bond pad structure and fabrication process for improved bonding quality by recessing oxides using a combination of SiO2 CMP process and dilute HF wet etching. In addition, in order to achieve improved wafer-level bonding, we introduced a seal design concept that prevents corrosion and provides extra mechanical support. Demonstrations of these concepts and processes provide the feasibility of reliable nano-scale 3D integration applications.

Non-mechanical optical path switching and its application to dual beam spectroscopy including gas filter correlation radiometry

NASA Technical Reports Server (NTRS)

Sachse, Glen W. (Inventor); Wang, Liang-Guo (Inventor)

1992-01-01

A non-mechanical optical switch is developed for alternately switching a monochromatic or quasi-monochromatic light beam along two optical paths. A polarizer polarizes light into a single, e.g., vertical component which is then rapidly modulated into vertical and horizontal components by a polarization modulator. A polarization beam splitter then reflects one of these components along one path and transmits the other along the second path. In the specific application of gas filter correlation radiometry, one path is directed through a vacuum cell and one path is directed through a gas correlation cell containing a desired gas. Reflecting mirrors cause these two paths to intersect at a second polarization beam splitter which reflects one component and transmits the other to recombine them into a polarization modulated beam which can be detected by an appropriate single sensor.

Software Architecture for a Virtual Environment for Nano Scale Assembly (VENSA).

PubMed

Lee, Yong-Gu; Lyons, Kevin W; Feng, Shaw C

2004-01-01

A Virtual Environment (VE) uses multiple computer-generated media to let a user experience situations that are temporally and spatially prohibiting. The information flow between the user and the VE is bidirectional and the user can influence the environment. The software development of a VE requires orchestrating multiple peripherals and computers in a synchronized way in real time. Although a multitude of useful software components for VEs exists, many of these are packaged within a complex framework and can not be used separately. In this paper, an architecture is presented which is designed to let multiple frameworks work together while being shielded from the application program. This architecture, which is called the Virtual Environment for Nano Scale Assembly (VENSA), has been constructed for interfacing with an optical tweezers instrument for nanotechnology development. However, this approach can be generalized for most virtual environments. Through the use of VENSA, the programmer can rely on existing solutions and concentrate more on the application software design.

Software Architecture for a Virtual Environment for Nano Scale Assembly (VENSA)

PubMed Central

Lee, Yong-Gu; Lyons, Kevin W.; Feng, Shaw C.

2004-01-01

A Virtual Environment (VE) uses multiple computer-generated media to let a user experience situations that are temporally and spatially prohibiting. The information flow between the user and the VE is bidirectional and the user can influence the environment. The software development of a VE requires orchestrating multiple peripherals and computers in a synchronized way in real time. Although a multitude of useful software components for VEs exists, many of these are packaged within a complex framework and can not be used separately. In this paper, an architecture is presented which is designed to let multiple frameworks work together while being shielded from the application program. This architecture, which is called the Virtual Environment for Nano Scale Assembly (VENSA), has been constructed for interfacing with an optical tweezers instrument for nanotechnology development. However, this approach can be generalized for most virtual environments. Through the use of VENSA, the programmer can rely on existing solutions and concentrate more on the application software design. PMID:27366610

EDITORIAL: Nonlinear optical manipulation, patterning and control in nano- and micro-scale systems Nonlinear optical manipulation, patterning and control in nano- and micro-scale systems

NASA Astrophysics Data System (ADS)

Denz, Cornelia; Simoni, Francesco

2009-03-01

Nonlinearities are becoming more and more important for a variety of applications in nanosciences, bio-medical sciences, information processing and photonics. For applications at the crossings of these fields, especially microscopic and nanoscopic imaging and manipulation, nonlinearities play a key role. They may range from simple nonlinear parameter changes up to applications in manipulating, controlling and structuring material by light, or the manipulation of light by light itself. It is this area between basic nonlinear optics and photonic applications that includes `hot' topics such as ultra-resolution optical microscopy, micro- and nanomanipulation and -structuring, or nanophotonics. This special issue contains contributions in this field, many of them from the International Conference on Nonlinear Microscopy and Optical Control held in conjunction with a network meeting of the ESF COST action MP0604 `Optical Micromanipulation by Nonlinear Nanophotonics', 19-22 February 2008, Münster, Germany. Throughout this special issue, basic investigations of material structuring by nonlinear light--matter interaction, light-induced control of nanoparticles, and novel nonlinear material investigation techniques, are presented, covering the basic field of optical manipulation and control. These papers are followed by impressive developments of optical tweezers. Nowadays, optical phase contrast tweezers, twin and especially multiple beam traps, develop particle control in a new dimension: particles can be arranged, sorted and identified with high throughput. One of the most prominent forthcoming applications of optical tweezers is in the field of microfluidics. The action of light on fluids will open new horizons in microfluidic manipulation and control. The field of optical manipulation and control is a very broad field that has developed in an impressive way, in a short time, in Europe with the installation of the MP0604 network. Top researchers from 19 countries are

Design of micro-ring optical sensors and circuits for integration on optical printed circuit boards (O-PCBs)

NASA Astrophysics Data System (ADS)

Lee, El-Hang; Lee, Hyun S.; Lee, S. G.; O, B. H.; Park, S. G.; Kim, K. H.

2007-05-01

We report on the design of micro-ring resonator optical sensors for integration on what we call optical printed circuit boards (O-PCBs). The objective is to realize application-specific O-PCBs, either on hard board or on flexible board, by integrating micro/nano-scale optical sensors for compact, light-weight, low-energy, high-speed, intelligent, and environmentally friendly processing of information. The O-PCBs consist of two-dimensional planar arrays of micro/nano-scale optical wires, circuits and devices that are interconnected and integrated to perform the functions of sensing and then storing, transporting, processing, switching, routing and distributing optical signals that have been collected by means of sensors. For fabrication, the polymer and organic optical wires and waveguides are first fabricated on a board and are used to interconnect and integrate sensors and other micro/ nano-scale photonic devices. Here, in our study, we focus on the sensors based on the micro-ring structures. We designed bio-sensors using silicon based micro-ring resonator. We investigate the characteristics such as sensitivity and selectivity (or quality factor) of micro-ring resonator for their use in bio-sensing application. We performed simulation studies on the quality factor of micro-ring resonators by varying the radius of the ring resonators and the separation between adjacent waveguides. We introduce the effective coupling coefficient as a realistic value to describe the strength of the coupling in micro-ring resonators.

Performance evaluation of bimodal thermite composites : nano- vs miron-scale particles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moore, K. M.; Pantoya, M.; Son, S. F.

2004-01-01

In recent years many studies of metastable interstitial composites (MIC) have shown vast combustion improvements over traditional thermite materials. The main difference between these two materials is the size of the fuel particles in the mixture. Decreasing the fuel size from the micron to nanometer range significantly increases the combustion wave speed and ignition sensitivity. Little is known, however, about the critical level of nano-sized fuel particles needed to enhance the performance of the traditional thermite. Ignition sensitivity experiments were performed using Al/MoO{sub 3} pellets at a theoretical maximum density of 50% (2 g/cm{sup 3}). The Al fuel particles weremore » prepared as bi-modal size distributions with micron (i.e., 4 and 20 {micro}m diameter) and nano-scale Al particles. The micron-scale Al was replaced in 10% increments by 80 nm Al particles until the fuel was 100% 80 nm Al. These bi-modal distributions allow the unique characteristics of nano-scale materials to be better understood. The pellets were ignited using a 50-W CO{sub 2} laser. High speed imaging diagnostics were used to measure ignition delay times, and micro-thermocouples were used to measure ignition temperatures. Combustion wave speeds were also examined.« less

LCRD Update and Path to Optical Relay Operations

NASA Technical Reports Server (NTRS)

Israel, David

2017-01-01

Speaker and Presenter at the Lincoln Laboratory Communications Workshop on May 23, 2017 at the Massachusetts Institute of Technology Lincoln Laboratory in Lexington, MA. This presentation discusses a concept for an evolution of NASAs optical communications near-Earth relay architecture. NASA's Laser Communications Relay Demonstration (LCRD) is a joint project between NASAs Goddard Space Flight Center (GSFC), the Jet Propulsion Laboratory California Institute of Technology (JPL), and the Massachusetts Institute of Technology Lincoln Laboratory (MIT LL). LCRD will provide a minimum of two years of high data rate optical communications service experiments in geosynchronous orbit (GEO) following launch in 2019. This presentation will provide an update of the LCRD mission status and planned capabilities and experiments, followed by a discussion of the path from LCRD to operational network capabilities.

Advanced nano lithography via soft materials-derived and reversible nano-patterning methodology for molding of infrared nano lenses

NASA Astrophysics Data System (ADS)

Park, Jae Hong; Jang, Hyun Ik; Park, Jun Yong; Jeon, Seok Woo; Kim, Woo Choong; Kim, Hee Yeoun; Ahn, Chi Won

2015-03-01

The methodology suggested in this research provides the great possibility of creating nanostructures composed of various materials, such as soft polymer, hard polymer, and metal, as well as Si. Such nanostructures are required for a vast range of optical and display devices, photonic components, physical devices, energy devices including electrodes of secondary batteries, fuel cells, solar cells, and energy harvesters, biological devices including biochips, biomimetic or biosimilar structured devices, and mechanical devices including micro- or nano-scale sensors and actuators.

Nano-optical conveyor belt, part II: Demonstration of handoff between near-field optical traps.

PubMed

Zheng, Yuxin; Ryan, Jason; Hansen, Paul; Cheng, Yao-Te; Lu, Tsung-Ju; Hesselink, Lambertus

2014-06-11

Optical tweezers have been widely used to manipulate biological and colloidal material, but the diffraction limit of far-field optics makes focused beams unsuitable for manipulating nanoscale objects with dimensions much smaller than the wavelength of light. While plasmonic structures have recently been successful in trapping nanoscale objects with high positioning accuracy, using such structures for manipulation over longer range has remained a significant challenge. In this work, we introduce a conveyor belt design based on a novel plasmonic structure, the resonant C-shaped engraving (CSE). We show how long-range manipulation is made possible by means of handoff between neighboring CSEs, and we present a simple technique for controlling handoff by rotating the polarization of laser illumination. We experimentally demonstrate handoff between a pair of CSEs for polystyrene spheres 200, 390, and 500 nm in diameter. We then extend this technique and demonstrate controlled particle transport down a 4.5 μm long "nano-optical conveyor belt."

Nano/micro-scale magnetophoretic devices for biomedical applications

NASA Astrophysics Data System (ADS)

Lim, Byeonghwa; Vavassori, Paolo; Sooryakumar, R.; Kim, CheolGi

2017-01-01

In recent years there have been tremendous advances in the versatility of magnetic shuttle technology using nano/micro-scale magnets for digital magnetophoresis. While the technology has been used for a wide variety of single-cell manipulation tasks such as selection, capture, transport, encapsulation, transfection, or lysing of magnetically labeled and unlabeled cells, it has also expanded to include parallel actuation and study of multiple bio-entities. The use of nano/micro-patterned magnetic structures that enable remote control of the applied forces has greatly facilitated integration of the technology with microfluidics, thereby fostering applications in the biomedical arena. The basic design and fabrication of various scaled magnets for remote manipulation of individual and multiple beads/cells, and their associated energies and forces that underlie the broad functionalities of this approach, are presented. One of the most useful features enabled by such advanced integrated engineering is the capacity to remotely tune the magnetic field gradient and energy landscape, permitting such multipurpose shuttles to be implemented within lab-on-chip platforms for a wide range of applications at the intersection of cellular biology and biotechnology.

Density functional theory studies on the nano-scaled composites consisted of graphene and acyl hydrazone molecules

NASA Astrophysics Data System (ADS)

Ren, J. L.; Zhou, L.; Lv, Z. C.; Ding, C. H.; Wu, Y. H.; Bai, H. C.

2016-07-01

Graphene, which is the first obtained single atomic layer 2D materials, has drawn a great of concern in nano biotechnology due to the unique property. On one hand, acyl hydrazone compounds belonging to the Schif bases have aroused considerable attention in medicine, pharmacy, and analytical reagent. However, few understanding about the interaction between graphene and acyl hydrazone molecules is now available. And such investigations are much crucial for the applications of these new nano-scaled composites. The current work revealed theoretical investigations on the nano-scaled composites built by acyl hydrazone molecules loaded on the surface of graphene. The relative energy, electronic property and the interaction between the counterparts of graphene/acyl hydrazone composites are investigated based on the density functional theory calculations. According to the obtained adsorption energy, the formation of the nano-scaled composite from the isolated graphene and acyl hydrazone molecule is exothermic, and thus it is energetically favorable to form these nano composites in viewpoint of total energy change. The frontier molecular orbital for the nano composite is mainly distributed at the graphene part, leading to that the energy levels of the frontier molecular orbital of the nano composites are very close to that of isolated graphene. Moreover, the counterpart interaction for the graphene/acyl hydrazone composites is also explored based on the discussions of orbital hybridization, charge redistribution and Van der Waals interaction.

Adaptive optics compensation over a 3 km near horizontal path

NASA Astrophysics Data System (ADS)

Mackey, Ruth; Dainty, Chris

2008-10-01

We present results of adaptive optics compensation at the receiver of a 3km optical link using a beacon laser operating at 635nm. The laser is transmitted from the roof of a seven-storey building over a near horizontal path towards a 127 mm optical receiver located on the second-floor of the Applied Optics Group at the National University of Ireland, Galway. The wavefront of the scintillated beam is measured using a Shack-Hartmann wavefront sensor (SHWFS) with high-speed CMOS camera capable of frame rates greater than 1kHz. The strength of turbulence is determined from the fluctuations in differential angle-of-arrival in the wavefront sensor measurements and from the degree of scintillation in the pupil plane. Adaptive optics compensation is applied using a tip-tilt mirror and 37 channel membrane mirror and controlled using a single desktop computer. The performance of the adaptive optics system in real turbulence is compared with the performance of the system in a controlled laboratory environment, where turbulence is generated using a liquid crystal spatial light modulator.

Nano-indentation and laser-induced damage testing in optical multilayer-dielectric gratings [Nanomechanics and laser-induced damage in optical multilayer dielectric gratings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mehrotra, K.; Corning Research & Development Corp., Coming, NY; Taylor, B. N.

Here, we demonstrate how a nanomechanical test can be used to generate metrics to complement laser-induced–damage testing (LIDT) measurements and show that differences in optical performance of the gratings (arising from changes in cleaning process and/or fabrication methods) can be related to their mechanical reliability. Data are presented on LIDT measurements in diffractive gratings of silica deposited on optical multilayers. The nano-indentation response of the diffraction gratings is measured in a new mode that allows for the extraction of a measurable metric characterizing the brittleness of the gratings, as well as their ductility. We show that lower LIDT’s are positivelymore » correlated with an increased grating brittleness, and therefore identify a nanomechanical approach to describe LIDT’s. We present extensive numerical simulations of nano-indentation tests and identify different deformation modes including stretching, shear concentration, and bending as precursors to mechanical failure in the nano-indentation test. The effects of geometrical inhomogeneities on enhanced stress generation in these gratings are specifically examined and addressed.« less

Nano-indentation and laser-induced damage testing in optical multilayer-dielectric gratings [Nanomechanics and laser-induced damage in optical multilayer dielectric gratings

DOE PAGES

Mehrotra, K.; Corning Research & Development Corp., Coming, NY; Taylor, B. N.; ...

2017-03-16

Here, we demonstrate how a nanomechanical test can be used to generate metrics to complement laser-induced–damage testing (LIDT) measurements and show that differences in optical performance of the gratings (arising from changes in cleaning process and/or fabrication methods) can be related to their mechanical reliability. Data are presented on LIDT measurements in diffractive gratings of silica deposited on optical multilayers. The nano-indentation response of the diffraction gratings is measured in a new mode that allows for the extraction of a measurable metric characterizing the brittleness of the gratings, as well as their ductility. We show that lower LIDT’s are positivelymore » correlated with an increased grating brittleness, and therefore identify a nanomechanical approach to describe LIDT’s. We present extensive numerical simulations of nano-indentation tests and identify different deformation modes including stretching, shear concentration, and bending as precursors to mechanical failure in the nano-indentation test. The effects of geometrical inhomogeneities on enhanced stress generation in these gratings are specifically examined and addressed.« less

Observation of Biological Tissues Using Common Path Optical Coherence Tomography with Gold Coated Conical Tip Lens Fiber

NASA Astrophysics Data System (ADS)

Taguchi, K.; Sugiyama, J.; Totsuka, M.; Imanaka, S.

2012-03-01

In this paper, we proposed a high lateral resolution common-path Fourier domain optical coherence tomography(OCT) system with the use of a chemically etched single mode fiber. In our experiments, single mode optical fiber for 1310nm was used for preparing the tapered tips. Our system used a conical microlens that was chemically etched by selective chemical etching technique using an etching solution of buffered hydrofluoric acid (BHF). From experimental results, we verified that our proposed optical coherence tomography system could operate as a common-path Fourier domain OCT system and conical tip lens fiber was very useful for a high lateral resolution common-path Fourier domain OCT system. Furthermore, we could observe a surface of paramecium bursaria and symbiotic chlorella in the paramecium bursaria using gold coated conical-tip fiber in the water.

Benefit of adaptive FEC in shared backup path protected elastic optical network.

PubMed

Guo, Hong; Dai, Hua; Wang, Chao; Li, Yongcheng; Bose, Sanjay K; Shen, Gangxiang

2015-07-27

We apply an adaptive forward error correction (FEC) allocation strategy to an Elastic Optical Network (EON) operated with shared backup path protection (SBPP). To maximize the protected network capacity that can be carried, an Integer Linear Programing (ILP) model and a spectrum window plane (SWP)-based heuristic algorithm are developed. Simulation results show that the FEC coding overhead required by the adaptive FEC scheme is significantly lower than that needed by a fixed FEC allocation strategy resulting in higher network capacity for the adaptive strategy. The adaptive FEC allocation strategy can also significantly outperform the fixed FEC allocation strategy both in terms of the spare capacity redundancy and the average FEC coding overhead needed per optical channel. The proposed heuristic algorithm is efficient and not only performs closer to the ILP model but also does much better than the shortest-path algorithm.

Simultaneous Water Vapor and Dry Air Optical Path Length Measurements and Compensation with the Large Binocular Telescope Interferometer

NASA Technical Reports Server (NTRS)

Defrere, D.; Hinz, P.; Downey, E.; Boehm, M.; Danchi, W. C.; Durney, O.; Ertel, S.; Hill, J. M.; Hoffmann, W. F.; Mennesson, B.;

Plasmonic Optical Fiber Sensor Based on Double Step Growth of Gold Nano-Islands

PubMed Central

Vasconcelos, Helena

2018-01-01

It is presented the fabrication and characterization of optical fiber sensors for refractive index measurement based on localized surface plasmon resonance (LSPR) with gold nano-islands obtained by single and by repeated thermal dewetting of gold thin films. Thin films of gold deposited on silica (SiO2) substrates and produced by different experimental conditions were analyzed by Scanning Electron Microscope/Dispersive X-ray Spectroscopy (SEM/EDS) and optical means, allowing identifying and characterizing the formation of nano-islands. The wavelength shift sensitivity to the surrounding refractive index of sensors produced by single and by repeated dewetting is compared. While for the single step dewetting, a wavelength shift sensitivity of ~60 nm/RIU was calculated, for the repeated dewetting, a value of ~186 nm/RIU was obtained, an increase of more than three times. It is expected that through changing the fabrication parameters and using other fiber sensor geometries, higher sensitivities may be achieved, allowing, in addition, for the possibility of tuning the plasmonic frequency. PMID:29677108

Plasmonic Optical Fiber Sensor Based on Double Step Growth of Gold Nano-Islands.

PubMed

de Almeida, José M M M; Vasconcelos, Helena; Jorge, Pedro A S; Coelho, Luis

2018-04-20

It is presented the fabrication and characterization of optical fiber sensors for refractive index measurement based on localized surface plasmon resonance (LSPR) with gold nano-islands obtained by single and by repeated thermal dewetting of gold thin films. Thin films of gold deposited on silica (SiO₂) substrates and produced by different experimental conditions were analyzed by Scanning Electron Microscope/Dispersive X-ray Spectroscopy (SEM/EDS) and optical means, allowing identifying and characterizing the formation of nano-islands. The wavelength shift sensitivity to the surrounding refractive index of sensors produced by single and by repeated dewetting is compared. While for the single step dewetting, a wavelength shift sensitivity of ~60 nm/RIU was calculated, for the repeated dewetting, a value of ~186 nm/RIU was obtained, an increase of more than three times. It is expected that through changing the fabrication parameters and using other fiber sensor geometries, higher sensitivities may be achieved, allowing, in addition, for the possibility of tuning the plasmonic frequency.

Crystallization of high-strength nano-scale leucite glass-ceramics.

PubMed

Theocharopoulos, A; Chen, X; Wilson, R M; Hill, R; Cattell, M J

2013-11-01

Fine-grained, high strength, translucent leucite dental glass-ceramics are synthesized via controlled crystallization of finely milled glass powders. The objectives of this study were to utilize high speed planetary milling of an aluminosilicate glass for controlled surface crystallization of nano-scale leucite glass-ceramics and to test the biaxial flexural strength. An aluminosilicate glass was synthesized, attritor or planetary milled and heat-treated. Glasses and glass-ceramics were characterized using particle size analysis, X-ray diffraction and scanning electron microscopy. Experimental (fine and nanoscale) and commercial (Ceramco-3, IPS Empress Esthetic) leucite glass-ceramics were tested using the biaxial flexural strength (BFS) test. Gaussian and Weibull statistics were applied. Experimental planetary milled glass-ceramics showed an increased leucite crystal number and nano-scale median crystal sizes (0.048-0.055 μm(2)) as a result of glass particle size reduction and heat treatments. Experimental materials had significantly (p<0.05) higher mean BFS and characteristic strength values than the commercial materials. Attritor milled and planetary milled (2h) materials showed no significant (p>0.05) strength difference. All other groups' mean BFS and characteristic strengths were found to be significantly different (p<0.05) to each other. The mean (SD) MPa strengths measured were: Attritor milled: 252.4 (38.7), Planetary milled: 225.4 (41.8) [4h milling] 255.0 (35.0) [2h milling], Ceramco-3: 75.7 (6.8) and IPS Empress: 165.5 (30.6). Planetary milling enabled synthesis of nano-scale leucite glass-ceramics with high flexural strength. These materials may help to reduce problems associated with brittle fracture of all-ceramic restorations and give reduced enamel wear. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Nano-imaging enabled via self-assembly

PubMed Central

McLeod, Euan; Ozcan, Aydogan

2014-01-01

SUMMARY Imaging object details with length scales below approximately 200 nm has been historically difficult for conventional microscope objective lenses because of their inability to resolve features smaller than one-half the optical wavelength. Here we review some of the recent approaches to surpass this limit by harnessing self-assembly as a fabrication mechanism. Self-assembly can be used to form individual nano- and micro-lenses, as well as to form extended arrays of such lenses. These lenses have been shown to enable imaging with resolutions as small as 50 nm half-pitch using visible light, which is well below the Abbe diffraction limit. Furthermore, self-assembled nano-lenses can be used to boost contrast and signal levels from small nano-particles, enabling them to be detected relative to background noise. Finally, alternative nano-imaging applications of self-assembly are discussed, including three-dimensional imaging, enhanced coupling from light-emitting diodes, and the fabrication of contrast agents such as quantum dots and nanoparticles. PMID:25506387

Synthesis, Optical and Photoluminescence Properties of Cu-Doped Zno Nano-Fibers Thin Films: Nonlinear Optics

NASA Astrophysics Data System (ADS)

Ganesh, V.; Salem, G. F.; Yahia, I. S.; Yakuphanoglu, F.

2018-03-01

Different concentrations of copper-doped zinc oxide thin films were coated on a glass substrate by sol-gel/spin-coating technique. The structural properties of pure and Cu-doped ZnO films were characterized by different techniques, i.e., atomic force microscopy (AFM), photoluminescence and UV-Vis-NIR spectroscopy. The AFM study revealed that pure and doped ZnO films are formed as nano-fibers with a granular structure. The photoluminescence spectra of these films showed a strong ultraviolet emission peak centered at 392 nm and a strong blue emission peak cantered at 450 nm. The optical band gap of the pure and copper-doped ZnO thin films calculated from optical transmission spectra (3.29-3.23 eV) were found to be increasing with increasing copper doping concentration. The refractive index dispersion curve of pure and Cu-doped ZnO film obeyed the single-oscillator model. The optical dispersion parameters such as E o , E d , and n_{∞}2 were calculated. Further, the nonlinear refractive index and nonlinear optical susceptibility were also calculated and interpreted.

A combined method for correlative 3D imaging of biological samples from macro to nano scale

NASA Astrophysics Data System (ADS)

Kellner, Manuela; Heidrich, Marko; Lorbeer, Raoul-Amadeus; Antonopoulos, Georgios C.; Knudsen, Lars; Wrede, Christoph; Izykowski, Nicole; Grothausmann, Roman; Jonigk, Danny; Ochs, Matthias; Ripken, Tammo; Kühnel, Mark P.; Meyer, Heiko

2016-10-01

Correlative analysis requires examination of a specimen from macro to nano scale as well as applicability of analytical methods ranging from morphological to molecular. Accomplishing this with one and the same sample is laborious at best, due to deformation and biodegradation during measurements or intermediary preparation steps. Furthermore, data alignment using differing imaging techniques turns out to be a complex task, which considerably complicates the interconnection of results. We present correlative imaging of the accessory rat lung lobe by combining a modified Scanning Laser Optical Tomography (SLOT) setup with a specially developed sample preparation method (CRISTAL). CRISTAL is a resin-based embedding method that optically clears the specimen while allowing sectioning and preventing degradation. We applied and correlated SLOT with Multi Photon Microscopy, histological and immunofluorescence analysis as well as Transmission Electron Microscopy, all in the same sample. Thus, combining CRISTAL with SLOT enables the correlative utilization of a vast variety of imaging techniques.

Exploring Chondrule and CAI Rims Using Micro- and Nano-Scale Petrological and Compositional Analysis

NASA Astrophysics Data System (ADS)

Cartwright, J. A.; Perez-Huerta, A.; Leitner, J.; Vollmer, C.

2017-12-01

As the major components within chondrites, chondrules (mm-sized droplets of quenched silicate melt) and calcium-aluminum-rich inclusions (CAI, refractory) represent the most abundant and the earliest materials that solidified from the solar nebula. However, the exact formation mechanisms of these clasts, and whether these processes are related, remains unconstrained, despite extensive petrological and compositional study. By taking advantage of recent advances in nano-scale tomographical techniques, we have undertaken a combined micro- and nano-scale study of CAI and chondrule rim morphologies, to investigate their formation mechanisms. The target lithologies for this research are Wark-Lovering rims (WLR), and fine-grained rims (FGR) around CAIs and chondrules respectively, present within many chondrites. The FGRs, which are up to 100 µm thick, are of particular interest as recent studies have identified presolar grains within them. These grains predate the formation of our Solar System, suggesting FGR formation under nebular conditions. By contrast, WLRs are 10-20 µm thick, made of different compositional layers, and likely formed by flash-heating shortly after CAI formation, thus recording nebular conditions. A detailed multi-scale study of these respective rims will enable us to better understand their formation histories and determine the potential for commonality between these two phases, despite reports of an observed formation age difference of up to 2-3 Myr. We are using a combination of complimentary techniques on our selected target areas: 1) Micro-scale characterization using standard microscopic and compositional techniques (SEM-EBSD, EMPA); 2) Nano-scale characterization of structures using transmission electron microscopy (TEM) and elemental, isotopic and tomographic analysis with NanoSIMS and atom probe tomography (APT). Preliminary nano-scale APT analysis of FGR morphologies within the Allende carbonaceous chondrite has successfully discerned

Optical Path Difference Fluctations at the CHARA Interferometric Array

NASA Astrophysics Data System (ADS)

Merand, A.; ten Brummelaar, T. A.; McAlister, H. A.; Ridgway, S. T.; Sturmann, J.; Sturmann, L.; Turner, N. H.; Bagnuolo, W. G.; Hrynevych, M.; Shure, M. A.

2001-05-01

Commissioning observations at the CHARA Array have been carried out with the two south telescopes, with a telescope separation of 34 meters. Due to the size of the array (>340 meters across) and the optical delay geometry, the beams travel horizontal distances of approximately 200 meters, with a number of reflections in the telescope coude area and the optical delay and beam combination areas. Stellar and laboratory observations have been analyzed to determine the variations of the optical path, as revealed by shifts in the interference pattern. The power spectra of the OPD variations are diagnostic of the atmospheric turbulence characteristics, and of any internal vibrations in the laboratory. Results of the OPD analysis will be compared to similar studies at other interferometric facilities. The CHARA Array, a six-telescope O/IR interferometric array operated by Georgia State University on Mt. Wilson, Calfornia, was funded by the National Science Foundation, the W.M. Keck Foundation, the David and Lucile Packard Foundation, and Georgia State University.

Common-path low-coherence interferometry fiber-optic sensor guided microincision

NASA Astrophysics Data System (ADS)

Zhang, Kang; Kang, Jin U.

2011-09-01

We propose and demonstrate a common-path low-coherence interferometry (CP-LCI) fiber-optic sensor guided precise microincision. The method tracks the target surface and compensates the tool-to-surface relative motion with better than +/-5 μm resolution using a precision micromotor connected to the tool tip. A single-fiber distance probe integrated microdissector was used to perform an accurate 100 μm incision into the surface of an Intralipid phantom. The CP-LCI guided incision quality in terms of depth was evaluated afterwards using three-dimensional Fourier-domain optical coherence tomography imaging, which showed significant improvement of incision accuracy compared to free-hand-only operations.

Common-path low-coherence interferometry fiber-optic sensor guided microincision

PubMed Central

Zhang, Kang; Kang, Jin U.

2011-01-01

We propose and demonstrate a common-path low-coherence interferometry (CP-LCI) fiber-optic sensor guided precise microincision. The method tracks the target surface and compensates the tool-to-surface relative motion with better than ±5 μm resolution using a precision micromotor connected to the tool tip. A single-fiber distance probe integrated microdissector was used to perform an accurate 100 μm incision into the surface of an Intralipid phantom. The CP-LCI guided incision quality in terms of depth was evaluated afterwards using three-dimensional Fourier-domain optical coherence tomography imaging, which showed significant improvement of incision accuracy compared to free-hand-only operations. PMID:21950912

Modeling Near-Crack-Tip Plasticity from Nano- to Micro-Scales

NASA Technical Reports Server (NTRS)

Glaessgen, Edward H.; Saether, Erik; Hochhalter, Jake D.; Yamakov, Vesselin I.

2010-01-01

Several efforts that are aimed at understanding the plastic deformation mechanisms related to crack propagation at the nano-, meso- and micro-length scales including atomistic simulation, discrete dislocation plasticity, strain gradient plasticity and crystal plasticity are discussed. The paper focuses on discussion of newly developed methodologies and their application to understanding damage processes in aluminum and its alloys. Examination of plastic mechanisms as a function of increasing length scale illustrates increasingly complex phenomena governing plasticity

Stability of retained austenite in high carbon steel under compressive stress: an investigation from macro to nano scale

PubMed Central

Hossain, R.; Pahlevani, F.; Quadir, M. Z.; Sahajwalla, V.

2016-01-01

Although high carbon martensitic steels are well known for their industrial utility in high abrasion and extreme operating environments, due to their hardness and strength, the compressive stability of their retained austenite, and the implications for the steels’ performance and potential uses, is not well understood. This article describes the first investigation at both the macro and nano scale of the compressive stability of retained austenite in high carbon martensitic steel. Using a combination of standard compression testing, X-ray diffraction, optical microstructure, electron backscattering diffraction imaging, electron probe micro-analysis, nano-indentation and micro-indentation measurements, we determined the mechanical stability of retained austenite and martensite in high carbon steel under compressive stress and identified the phase transformation mechanism, from the macro to the nano level. We found at the early stage of plastic deformation hexagonal close-packed (HCP) martensite formation dominates, while higher compression loads trigger body-centred tetragonal (BCT) martensite formation. The combination of this phase transformation and strain hardening led to an increase in the hardness of high carbon steel of around 30%. This comprehensive characterisation of stress induced phase transformation could enable the precise control of the microstructures of high carbon martensitic steels, and hence their properties. PMID:27725722

An automatic alignment system for measuring optical path of transmissometer based on light beam scanning

NASA Astrophysics Data System (ADS)

Zhou, Shudao; Ma, Zhongliang; Wang, Min; Peng, Shuling

2018-05-01

This paper proposes a novel alignment system based on the measurement of optical path using a light beam scanning mode in a transmissometer. The system controls both the probe beam and the receiving field of view while scanning in two vertical directions. The system then calculates the azimuth angle of the transmitter and the receiver to determine the precise alignment of the optical path. Experiments show that this method can determine the alignment angles in less than 10 min with errors smaller than 66 μrad in the azimuth. This system also features high collimation precision, process automation and simple installation.

Controlling high-throughput manufacturing at the nano-scale

NASA Astrophysics Data System (ADS)

Cooper, Khershed P.

2013-09-01

Interest in nano-scale manufacturing research and development is growing. The reason is to accelerate the translation of discoveries and inventions of nanoscience and nanotechnology into products that would benefit industry, economy and society. Ongoing research in nanomanufacturing is focused primarily on developing novel nanofabrication techniques for a variety of applications—materials, energy, electronics, photonics, biomedical, etc. Our goal is to foster the development of high-throughput methods of fabricating nano-enabled products. Large-area parallel processing and highspeed continuous processing are high-throughput means for mass production. An example of large-area processing is step-and-repeat nanoimprinting, by which nanostructures are reproduced again and again over a large area, such as a 12 in wafer. Roll-to-roll processing is an example of continuous processing, by which it is possible to print and imprint multi-level nanostructures and nanodevices on a moving flexible substrate. The big pay-off is high-volume production and low unit cost. However, the anticipated cost benefits can only be realized if the increased production rate is accompanied by high yields of high quality products. To ensure product quality, we need to design and construct manufacturing systems such that the processes can be closely monitored and controlled. One approach is to bring cyber-physical systems (CPS) concepts to nanomanufacturing. CPS involves the control of a physical system such as manufacturing through modeling, computation, communication and control. Such a closely coupled system will involve in-situ metrology and closed-loop control of the physical processes guided by physics-based models and driven by appropriate instrumentation, sensing and actuation. This paper will discuss these ideas in the context of controlling high-throughput manufacturing at the nano-scale.

Fabrication of a 3D micro/nano dual-scale carbon array and its demonstration as the microelectrodes for supercapacitors

NASA Astrophysics Data System (ADS)

Jiang, Shulan; Shi, Tielin; Gao, Yang; Long, Hu; Xi, Shuang; Tang, Zirong

2014-04-01

An easily accessible method is proposed for the fabrication of a 3D micro/nano dual-scale carbon array with a large surface area. The process mainly consists of three critical steps. Firstly, a hemispherical photoresist micro-array was obtained by the cost-effective nanoimprint lithography process. Then the micro-array was transformed into hierarchical structures with longitudinal nanowires on the microstructure surface by oxygen plasma etching. Finally, the micro/nano dual-scale carbon array was fabricated by carbonizing these hierarchical photoresist structures. It has also been demonstrated that the micro/nano dual-scale carbon array can be used as the microelectrodes for supercapacitors by the electrodeposition of a manganese dioxide (MnO2) film onto the hierarchical carbon structures with greatly enhanced electrochemical performance. The specific gravimetric capacitance of the deposited micro/nano dual-scale microelectrodes is estimated to be 337 F g-1 at the scan rate of 5 mV s-1. This proposed approach of fabricating a micro/nano dual-scale carbon array provides a facile way in large-scale microstructures’ manufacturing for a wide variety of applications, including sensors and on-chip energy storage devices.

Optical study of xanthene-type dyes in nano-confined liquid

NASA Astrophysics Data System (ADS)

Mahdi Shavakandi, Seyyed; Alizadeh, Khalil; Sharifi, Soheil; Marti, Othmar; Amirkhani, Masoud

2017-04-01

The optical activity of dye molecules in different environments is of great interest for many applications such as laser system or biological imaging. We investigate the fluorescence and absorption spectrum of nano-confined xanthene dyes (RhB and fluorescein sodium salt) in a two-phase liquid. Each show very distinct optical behavior in the water phase of a reverse microemulsion. Their optical properties such as absorption and fluorescence for different concentrations of dye and nanodroplets are investigated. We show that for the same concentration of dye in the microemulsion the peak of fluorescence intensity is varied by altering the concentration of nanodroplets. However, the trend of the change is widely different depending on the hydrophobicity of dyes. Quantum-mechanical second order perturbation theory is used to calculate the ratio of dipole moments in the ground and excited states, which accounts for the Stokes shift in fluorescence peak. Photon correlation spectroscopy is employed to check the trace of the dye in the oil phase of the microemulsion.

Hard and flexible optical printed circuit board

NASA Astrophysics Data System (ADS)

Lee, El-Hang; Lee, Hyun Sik; Lee, S. G.; O, B. H.; Park, S. G.; Kim, K. H.

2007-02-01

We report on the design and fabrication of hard and flexible optical printed circuit boards (O-PCBs). The objective is to realize generic and application-specific O-PCBs, either in hard form or flexible form, that are compact, light-weight, low-energy, high-speed, intelligent, and environmentally friendly, for low-cost and high-volume universal applications. The O-PCBs consist of 2-dimensional planar arrays of micro/nano-scale optical wires, circuits and devices that are interconnected and integrated to perform the functions of sensing, storing, transporting, processing, switching, routing and distributing optical signals on flat modular boards. For fabrication, the polymer and organic optical wires and waveguides are first fabricated on a board and are used to interconnect and integrate micro/nano-scale photonic devices. The micro/nano-optical functional devices include lasers, detectors, switches, sensors, directional couplers, multi-mode interference devices, ring-resonators, photonic crystal devices, plasmonic devices, and quantum devices. For flexible boards, the optical waveguide arrays are fabricated on flexible poly-ethylen terephthalate (PET) substrates by UV embossing. Electrical layer carrying VCSEL and PD array is laminated with the optical layer carrying waveguide arrays. Both hard and flexible electrical lines are replaced with high speed optical interconnection between chips over four waveguide channels up to 10Gbps on each. We discuss uses of hard or flexible O-PCBs for telecommunication systems, computer systems, transportation systems, space/avionic systems, and bio-sensor systems.

Electro-Optic Effects in Colloidal Dispersion of Metal Nano-Rods in Dielectric Fluid

PubMed Central

Golovin, Andrii B.; Xiang, Jie; Park, Heung-Shik; Tortora, Luana; Nastishin, Yuriy A.; Shiyanovskii, Sergij V.; Lavrentovich, Oleg D.

2011-01-01

In modern transformation optics, one explores metamaterials with properties that vary from point to point in space and time, suitable for application in devices such as an “optical invisibility cloak” and an “optical black hole”. We propose an approach to construct spatially varying and switchable metamaterials that are based on colloidal dispersions of metal nano-rods (NRs) in dielectric fluids, in which dielectrophoretic forces, originating in the electric field gradients, create spatially varying configurations of aligned NRs. The electric field controls orientation and concentration of NRs and thus modulates the optical properties of the medium. Using gold (Au) NRs dispersed in toluene, we demonstrate electrically induced change in refractive index on the order of 0.1. PMID:28879997

Surface roughness: A review of its measurement at micro-/nano-scale

NASA Astrophysics Data System (ADS)

Gong, Yuxuan; Xu, Jian; Buchanan, Relva C.

2018-01-01

The measurement of surface roughness at micro-/nano-scale is of great importance to metrological, manufacturing, engineering, and scientific applications given the critical roles of roughness in physical and chemical phenomena. The surface roughness of materials can significantly change the way of how they interact with light, phonons, molecules, and so forth, thus surface roughness ultimately determines the functionality and property of materials. In this short review, the techniques of measuring micro-/nano-scale surface roughness are discussed with special focus on the limitations and capabilities of each technique. In addition, the calculations of surface roughness and their theoretical background are discussed to offer readers a better understanding of the importance of post-measurement analysis. Recent progress on fractal analysis of surface roughness is discussed to shed light on the future efforts in surface roughness measurement.

Optical rectification using geometrical field enhancement in gold nano-arrays

NASA Astrophysics Data System (ADS)

Piltan, S.; Sievenpiper, D.

2017-11-01

Conversion of photons to electrical energy has a wide variety of applications including imaging, solar energy harvesting, and IR detection. A rectenna device consists of an antenna in addition to a rectifying element to absorb the incident radiation within a certain frequency range. We designed, fabricated, and measured an optical rectifier taking advantage of asymmetrical field enhancement for forward and reverse currents due to geometrical constraints. The gold nano-structures as well as the geometrical parameters offer enhanced light-matter interaction at 382 THz. Using the Taylor expansion of the time-dependent current as a function of the external bias and oscillating optical excitation, we obtained responsivities close to quantum limit of operation. This geometrical approach can offer an efficient, broadband, and scalable solution for energy conversion and detection in the future.

Preferential flow paths in fractured rock detected by cross-borehole nano-iron tracer test

NASA Astrophysics Data System (ADS)

Chia, Yeeping; Chuang, Po-Yu

2017-04-01

Characterization of the preferential flow paths and their hydraulic properties is desirable for developing a hydrogeological conceptual model in fractured rock. However, the heterogeneity and anisotropy of the hydraulic property often make it difficult to understand groundwater flow paths through fractures. In this study, we adopted nanoscale zero-valent iron (nZVI) as a tracer to characterize fracture connectivity and hydraulic properties. A magnet array was placed in an observation well to attract arriving nZVI particles for identifying the location of incoming tracer. This novel approach was developed for the investigation of fracture flow at a hydrogeological research station in central Taiwan. A heat-pulse flowmeter test was performed to delineate the vertical distribution of permeable fractures in two boreholes, making it possible to design a field tracer test. The nZVI slurry was released in the sealed injection well. The arrival of the slurry in the observation well was evidenced by a breakthrough curve recorded by the fluid conductivity sensor as well as the nZVI particles attracted to the magnets. The iron nanoparticles attracted to the magnets provide the quantitative criteria for locating the position of tracer inlet in the observation well. The position of the magnet attracting the maximum weight of iron nanoparticles agrees well with the depth of a permeable fracture zone delineated by the flowmeter. Besides, a conventional saline tracer test was conducted in the field, producing a similar outcome as the nZVI tracer test. Our study results indicate that the nano-iron tracer test could be a promising method for the characterization of the preferential flow paths in fractured rock.

Radiative control of dark excitons at room temperature by nano-optical antenna-tip Purcell effect

NASA Astrophysics Data System (ADS)

Park, Kyoung-Duck; Jiang, Tao; Clark, Genevieve; Xu, Xiaodong; Raschke, Markus B.

2018-01-01

Excitons, Coulomb-bound electron-hole pairs, are elementary photo-excitations in semiconductors that can couple to light through radiative relaxation. In contrast, dark excitons (XD) show anti-parallel spin configuration with generally forbidden radiative emission. Because of their long lifetimes, these dark excitons are appealing candidates for quantum computing and optoelectronics. However, optical read-out and control of XD states has remained challenging due to their decoupling from light. Here, we present a tip-enhanced nano-optical approach to induce, switch and programmably modulate the XD emission at room temperature. Using a monolayer transition metal dichalcogenide (TMD) WSe2 on a gold substrate, we demonstrate 6 × 105-fold enhancement in dark exciton photoluminescence quantum yield achieved through coupling of the antenna-tip to the dark exciton out-of-plane optical dipole moment, with a large Purcell factor of ≥2 × 103 of the tip-sample nano-cavity. Our approach provides a facile way to harness excitonic properties in low-dimensional semiconductors offering new strategies for quantum optoelectronics.

Radiative control of dark excitons at room temperature by nano-optical antenna-tip Purcell effect.

PubMed

Park, Kyoung-Duck; Jiang, Tao; Clark, Genevieve; Xu, Xiaodong; Raschke, Markus B

2018-01-01

Excitons, Coulomb-bound electron-hole pairs, are elementary photo-excitations in semiconductors that can couple to light through radiative relaxation. In contrast, dark excitons (X D ) show anti-parallel spin configuration with generally forbidden radiative emission. Because of their long lifetimes, these dark excitons are appealing candidates for quantum computing and optoelectronics. However, optical read-out and control of X D states has remained challenging due to their decoupling from light. Here, we present a tip-enhanced nano-optical approach to induce, switch and programmably modulate the X D emission at room temperature. Using a monolayer transition metal dichalcogenide (TMD) WSe 2 on a gold substrate, we demonstrate ~6 × 10 5 -fold enhancement in dark exciton photoluminescence quantum yield achieved through coupling of the antenna-tip to the dark exciton out-of-plane optical dipole moment, with a large Purcell factor of ≥2 × 10 3 of the tip-sample nano-cavity. Our approach provides a facile way to harness excitonic properties in low-dimensional semiconductors offering new strategies for quantum optoelectronics.

Remarkable Second-Order Optical Nonlinearity of Nano-Sized Au Cluster: A TDDFT Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Kechen; Li, Jun; Lin, Chensheng

2004-04-21

The dipole polarizability, static first hyperpolarizability, and UV-vis spectrum of the recently identified nano-sized tetrahedral cluster of Au have been investigated by using time-dependent density functional response theory. We have discovered that the Au cluster possesses remarkably large molecular second-order optical nonlinearity with the first hyperpolarizabilty (xyz) calculated to be 14.3 x 10 electrostatic unit (esu). The analysis of the low-energy absorption band suggests that the charge transfer from the edged gold atoms to the vertex ones plays the key role in nonlinear optical (NLO) response of Au.

Advances in optoplasmonic sensors - combining optical nano/microcavities and photonic crystals with plasmonic nanostructures and nanoparticles

NASA Astrophysics Data System (ADS)

Xavier, Jolly; Vincent, Serge; Meder, Fabian; Vollmer, Frank

2018-01-01

Nanophotonic device building blocks, such as optical nano/microcavities and plasmonic nanostructures, lie at the forefront of sensing and spectrometry of trace biological and chemical substances. A new class of nanophotonic architecture has emerged by combining optically resonant dielectric nano/microcavities with plasmonically resonant metal nanostructures to enable detection at the nanoscale with extraordinary sensitivity. Initial demonstrations include single-molecule detection and even single-ion sensing. The coupled photonic-plasmonic resonator system promises a leap forward in the nanoscale analysis of physical, chemical, and biological entities. These optoplasmonic sensor structures could be the centrepiece of miniaturised analytical laboratories, on a chip, with detection capabilities that are beyond the current state of the art. In this paper, we review this burgeoning field of optoplasmonic biosensors. We first focus on the state of the art in nanoplasmonic sensor structures, high quality factor optical microcavities, and photonic crystals separately before proceeding to an outline of the most recent advances in hybrid sensor systems. We discuss the physics of this modality in brief and each of its underlying parts, then the prospects as well as challenges when integrating dielectric nano/microcavities with metal nanostructures. In Section 5, we hint to possible future applications of optoplasmonic sensing platforms which offer many degrees of freedom towards biomedical diagnostics at the level of single molecules.

An approach to control tuning range and speed in 1D ternary photonic band gap material nano-layered optical filter structures electro-optically

NASA Astrophysics Data System (ADS)

Zia, Shahneel; Banerjee, Anirudh

2016-05-01

This paper demonstrates a way to control spectrum tuning capability in one-dimensional (1D) ternary photonic band gap (PBG) material nano-layered structures electro-optically. It is shown that not only tuning range, but also tuning speed of tunable optical filters based on 1D ternary PBG structures can be controlled Electro-optically. This approach finds application in tuning range enhancement of 1D Ternary PBG structures and compensating temperature sensitive transmission spectrum shift in 1D Ternary PBG structures.

An approach to control tuning range and speed in 1D ternary photonic band gap material nano-layered optical filter structures electro-optically

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zia, Shahneel, E-mail: shahneelzia@gmail.com; Banerjee, Anirudh, E-mail: abanerjee@amity.edu

2016-05-06

This paper demonstrates a way to control spectrum tuning capability in one-dimensional (1D) ternary photonic band gap (PBG) material nano-layered structures electro-optically. It is shown that not only tuning range, but also tuning speed of tunable optical filters based on 1D ternary PBG structures can be controlled Electro-optically. This approach finds application in tuning range enhancement of 1D Ternary PBG structures and compensating temperature sensitive transmission spectrum shift in 1D Ternary PBG structures.

The silicon chip: A versatile micro-scale platform for micro- and nano-scale systems

NASA Astrophysics Data System (ADS)

Choi, Edward

Cutting-edge advances in micro- and nano-scale technology require instrumentation to interface with the external world. While technology feature sizes are continually being reduced, the size of experimentalists and their instrumentation do not mirror this trend. Hence there is a need for effective application-specific instrumentation to bridge the gap from the micro and nano-scale phenomena being studied to the comparative macro-scale of the human interfaces. This dissertation puts forward the idea that the silicon CMOS integrated circuit, or microchip in short, serves as an excellent platform to perform this functionality. The electronic interfaces designed for the semiconductor industry are particularly attractive as development platforms, and the reduction in feature sizes that has been a hallmark of the industry suggests that chip-scale instrumentation may be more closely coupled to the phenomena of interest, allowing finer control or improved measurement capabilities. Compatibility with commercial processes will further enable economies of scale through mass production, another welcome feature of this approach. Thus chip-scale instrumentation may replace the bulky, expensive, cumbersome-to-operate macro-scale prototypes currently in use for many of these applications. The dissertation examines four specific applications in which the chip may serve as the ideal instrumentation platform. These are nanorod manipulation, polypyrrole bilayer hinge microactuator control, organic transistor hybrid circuits, and contact fluorescence imaging. The thesis is structured around chapters devoted to each of these projects, in addition to a chapter on preliminary work on an RFID system that serves as a wireless interface model. Each of these chapters contains tools and techniques developed for chip-scale instrumentation, from custom scripts for automated layout and data collection to microfabrication processes. Implementation of these tools to develop systems for the

Optical modeling based on mean free path calculations for quantum dot phosphors applied to optoelectronic devices.

PubMed

Shin, Min-Ho; Kim, Hyo-Jun; Kim, Young-Joo

2017-02-20

We proposed an optical simulation model for the quantum dot (QD) nanophosphor based on the mean free path concept to understand precisely the optical performance of optoelectronic devices. A measurement methodology was also developed to get the desired optical characteristics such as the mean free path and absorption spectra for QD nanophosphors which are to be incorporated into the simulation. The simulation results for QD-based white LED and OLED displays show good agreement with the experimental values from the fabricated devices in terms of spectral power distribution, chromaticity coordinate, CCT, and CRI. The proposed simulation model and measurement methodology can be applied easily to the design of lots of optoelectronics devices using QD nanophosphors to obtain high efficiency and the desired color characteristics.

Complete description of the optical path difference of a novel spectral zooming imaging spectrometer

NASA Astrophysics Data System (ADS)

Li, Jie; Wu, Haiying; Qi, Chun

2018-03-01

A complete description of the optical path difference of a novel spectral zooming imaging spectrometer (SZIS) is presented. SZIS is designed based on two identical Wollaston prisms with an adjustable air gap. Thus, interferogram with arbitrary spectral resolution and great reduction of spectral image size can be conveniently formed to adapt to different application requirements. Ray tracing modeling in arbitrary incidence with a quasi-parallel-plate approximation scheme is proposed to analyze the optical path difference of SZIS. In order to know the characteristics of the apparatus, exact calculations of the corresponding spectral resolution and field of view are both derived and analyzed in detail. We also present a comparison of calculation and experiment to prove the validity of the theory.

Random fluctuations of optical signal path delay in the atmosphere

NASA Astrophysics Data System (ADS)

Kral, L.; Prochazka, I.; Hamal, K.

2006-09-01

Atmospheric turbulence induces random delay fluctuations to any optical signal transmitted through the air. These fluctuations can influence for example the measurement precision of laser rangefinders. We have found an appropriate theoretical model based on geometrical optics that allows us to predict the amplitude of the random delay fluctuations for different observing conditions. We have successfully proved the applicability of this model by a series of experiments, directly determining the amplitude of the turbulence-induced pulse delay fluctuations by analysis of a high precision laser ranging data. Moreover, we have also shown that a standard theoretical approach based on diffractive propagation of light through inhomogeneous media and implemented using the GLAD software is not suitable for modeling of the optical signal delay fluctuations caused by the atmosphere. These models based on diffractive propagation predict the turbulence-induced optical path length fluctuations of the order of micrometers, whereas the fluctuations predicted by the geometrical optics model (in agreement with our experimental data) are generally larger by two orders of magnitude, i.e. in the submillimeter range. The reason of this discrepancy is a subject to discussion.

Simultaneous water vapor and dry air optical path length measurements and compensation with the large binocular telescope interferometer

NASA Astrophysics Data System (ADS)

Defrère, D.; Hinz, P.; Downey, E.; Böhm, M.; Danchi, W. C.; Durney, O.; Ertel, S.; Hill, J. M.; Hoffmann, W. F.; Mennesson, B.; Millan-Gabet, R.; Montoya, M.; Pott, J.-U.; Skemer, A.; Spalding, E.; Stone, J.; Vaz, A.

2016-08-01

The Large Binocular Telescope Interferometer uses a near-infrared camera to measure the optical path length variations between the two AO-corrected apertures and provide high-angular resolution observations for all its science channels (1.5-13 microns). There is however a wavelength dependent component to the atmospheric turbulence, which can introduce optical path length errors when observing at a wavelength different from that of the fringe sensing camera. Water vapor in particular is highly dispersive and its effect must be taken into account for high-precision infrared interferometric observations as described previously for VLTI/MIDI or the Keck Interferometer Nuller. In this paper, we describe the new sensing approach that has been developed at the LBT to measure and monitor the optical path length fluctuations due to dry air and water vapor separately. After reviewing the current performance of the system for dry air seeing compensation, we present simultaneous H-, K-, and N-band observations that illustrate the feasibility of our feedforward approach to stabilize the path length fluctuations seen by the LBTI nuller.

High-Bandwidth Dynamic Full-Field Profilometry for Nano-Scale Characterization of MEMS

NASA Astrophysics Data System (ADS)

Chen, Liang-Chia; Huang, Yao-Ting; Chang, Pi-Bai

2006-10-01

The article describes an innovative optical interferometric methodology to delivery dynamic surface profilometry with a measurement bandwidth up to 10MHz or higher and a vertical resolution up to 1 nm. Previous work using stroboscopic microscopic interferometry for dynamic characterization of micro (opto)electromechanical systems (M(O)EMS) has been limited in measurement bandwidth mainly within a couple of MHz. For high resonant mode analysis, the stroboscopic light pulse is insufficiently short to capture the moving fringes from dynamic motion of the detected structure. In view of this need, a microscopic prototype based on white-light stroboscopic interferometry with an innovative light superposition strategy was developed to achieve dynamic full-field profilometry with a high measurement bandwidth up to 10MHz or higher. The system primarily consists of an optical microscope, on which a Mirau interferometric objective embedded with a piezoelectric vertical translator, a high-power LED light module with dual operation modes and light synchronizing electronics unit are integrated. A micro cantilever beam used in AFM was measured to verify the system capability in accurate characterisation of dynamic behaviours of the device. The full-field seventh-mode vibration at a vibratory frequency of 3.7MHz can be fully characterized and nano-scale vertical measurement resolution as well as tens micrometers of vertical measurement range can be performed.

Optical spins and nano-antenna array for magnetic therapy.

PubMed

Thammawongsa, N; Mitatha, S; Yupapin, P P

2013-09-01

Magnetic therapy is an alternative medicine practice involving the use of magnetic fields subjected to certain parts of the body and stimulates healing from a range of health problems. In this paper, an embedded nano-antenna system using the optical spins generated from a particular configuration of microrings (PANDA) is proposed. The orthogonal solitons pairs corresponding to the left-hand and right-hand optical solitons (photons) produced from dark-bright soliton conversion can be simultaneously detected within the system at the output ports. Two possible spin states which are assigned as angular momentum of either +ħ or -ħ will be absorbed by an object whenever this set of orthogonal solitons is imparted to the object. Magnetic moments could indeed arise from the intrinsic property of spins. By controlling some important parameters of the system such as soliton input power, coupling coefficients and sizes of rings, output signals from microring resonator system can be tuned and optimized to be used as magnetic therapy array.

Statistical analysis of measured free-space laser signal intensity over a 2.33 km optical path.

PubMed

Tunick, Arnold

2007-10-17

Experimental research is conducted to determine the characteristic behavior of high frequency laser signal intensity data collected over a 2.33 km optical path. Results focus mainly on calculated power spectra and frequency distributions. In addition, a model is developed to calculate optical turbulence intensity (C(n)/2) as a function of receiving and transmitting aperture diameter, log-amplitude variance, and path length. Initial comparisons of calculated to measured C(n)/2 data are favorable. It is anticipated that this kind of signal data analysis will benefit laser communication systems development and testing at the U.S. Army Research Laboratory (ARL) and elsewhere.

Phototoxicity and Dosimetry of Nano-scaleTitanium Dioxide in Aquatic Organisms

EPA Science Inventory

We have been testing nanoscale TiO2 (primarily Evonik P25) in acute exposures to identify and quantify its phototoxicity under solar simulated radiation (SSR), and to develop dose metrics reflective of both nano-scale properties and the photon component of its potency. Several e...

Phototoxicity and Dosimetry of Nano-scale Titanium Dioxide in Aquatic Organisms

EPA Science Inventory

We have been testing nanoscale TiO2 (primarily Evonik P25) in acute exposures to identify and quantify its phototoxicity under solar simulated radiation (SSR), and to develop dose metrics reflective of both nano-scale properties and the photon component of its potency. Several e...

Nano-scale surface morphology, wettability and osteoblast adhesion on nitrogen plasma-implanted NiTi shape memory alloy.

PubMed

Liu, X M; Wu, S L; Chu, Paul K; Chung, C Y; Chu, C L; Chan, Y L; Lam, K O; Yeung, K W K; Lu, W W; Cheung, K M C; Luk, K D K

2009-06-01

Plasma immersion ion implantation (PIII) is an effective method to increase the corrosion resistance and inhibit nickel release from orthopedic NiTi shape memory alloy. Nitrogen was plasma-implanted into NiTi using different pulsing frequencies to investigate the effects on the nano-scale surface morphology, structure, wettability, as well as biocompatibility. X-ray photoelectron spectroscopy (XPS) results show that the implantation depth of nitrogen increases with higher pulsing frequencies. Atomic force microscopy (AFM) discloses that the nano-scale surface roughness increases and surface features are changed from islands to spiky cones with higher pulsing frequencies. This variation in the nano surface structures leads to different surface free energy (SFE) monitored by contact angle measurements. The adhesion, spreading, and proliferation of osteoblasts on the implanted NiTi surface are assessed by cell culture tests. Our results indicate that the nano-scale surface morphology that is altered by the implantation frequencies impacts the surface free energy and wettability of the NiTi surfaces, and in turn affects the osteoblast adhesion behavior.

Investigation of nuclear nano-morphology marker as a biomarker for cancer risk assessment using a mouse model

NASA Astrophysics Data System (ADS)

Bista, Rajan K.; Uttam, Shikhar; Hartman, Douglas J.; Qiu, Wei; Yu, Jian; Zhang, Lin; Brand, Randall E.; Liu, Yang

2012-06-01

The development of accurate and clinically applicable tools to assess cancer risk is essential to define candidates to undergo screening for early-stage cancers at a curable stage or provide a novel method to monitor chemoprevention treatments. With the use of our recently developed optical technology--spatial-domain low-coherence quantitative phase microscopy (SL-QPM), we have derived a novel optical biomarker characterized by structure-derived optical path length (OPL) properties from the cell nucleus on the standard histology and cytology specimens, which quantifies the nano-structural alterations within the cell nucleus at the nanoscale sensitivity, referred to as nano-morphology marker. The aim of this study is to evaluate the feasibility of the nuclear nano-morphology marker from histologically normal cells, extracted directly from the standard histology specimens, to detect early-stage carcinogenesis, assess cancer risk, and monitor the effect of chemopreventive treatment. We used a well-established mouse model of spontaneous carcinogenesis--ApcMin mice, which develop multiple intestinal adenomas (Min) due to a germline mutation in the adenomatous polyposis coli (Apc) gene. We found that the nuclear nano-morphology marker quantified by OPL detects the development of carcinogenesis from histologically normal intestinal epithelial cells, even at an early pre-adenomatous stage (six weeks). It also exhibits a good temporal correlation with the small intestine that parallels the development of carcinogenesis and cancer risk. To further assess its ability to monitor the efficacy of chemopreventive agents, we used an established chemopreventive agent, sulindac. The nuclear nano-morphology marker is reversed toward normal after a prolonged treatment. Therefore, our proof-of-concept study establishes the feasibility of the SL-QPM derived nuclear nano-morphology marker OPL as a promising, simple and clinically applicable biomarker for cancer risk assessment and

Corrections to scaling for watersheds, optimal path cracks, and bridge lines

NASA Astrophysics Data System (ADS)

Fehr, E.; Schrenk, K. J.; Araújo, N. A. M.; Kadau, D.; Grassberger, P.; Andrade, J. S., Jr.; Herrmann, H. J.

2012-07-01

We study the corrections to scaling for the mass of the watershed, the bridge line, and the optimal path crack in two and three dimensions (2D and 3D). We disclose that these models have numerically equivalent fractal dimensions and leading correction-to-scaling exponents. We conjecture all three models to possess the same fractal dimension, namely, df=1.2168±0.0005 in 2D and df=2.487±0.003 in 3D, and the same exponent of the leading correction, Ω=0.9±0.1 and Ω=1.0±0.1, respectively. The close relations between watersheds, optimal path cracks in the strong disorder limit, and bridge lines are further supported by either heuristic or exact arguments.

Semiclassical Path Integral Calculation of Nonlinear Optical Spectroscopy.

PubMed

Provazza, Justin; Segatta, Francesco; Garavelli, Marco; Coker, David F

2018-02-13

Computation of nonlinear optical response functions allows for an in-depth connection between theory and experiment. Experimentally recorded spectra provide a high density of information, but to objectively disentangle overlapping signals and to reach a detailed and reliable understanding of the system dynamics, measurements must be integrated with theoretical approaches. Here, we present a new, highly accurate and efficient trajectory-based semiclassical path integral method for computing higher order nonlinear optical response functions for non-Markovian open quantum systems. The approach is, in principle, applicable to general Hamiltonians and does not require any restrictions on the form of the intrasystem or system-bath couplings. This method is systematically improvable and is shown to be valid in parameter regimes where perturbation theory-based methods qualitatively breakdown. As a test of the methodology presented here, we study a system-bath model for a coupled dimer for which we compare against numerically exact results and standard approximate perturbation theory-based calculations. Additionally, we study a monomer with discrete vibronic states that serves as the starting point for future investigation of vibronic signatures in nonlinear electronic spectroscopy.

Multi-scale Observation of Biological Interactions of Nanocarriers: from Nano to Macro

PubMed Central

Jin, Su-Eon; Bae, Jin Woo; Hong, Seungpyo

2010-01-01

Microscopic observations have played a key role in recent advancements in nanotechnology-based biomedical sciences. In particular, multi-scale observation is necessary to fully understand the nano-bio interfaces where a large amount of unprecedented phenomena have been reported. This review describes how to address the physicochemical and biological interactions of nanocarriers within the biological environments using microscopic tools. The imaging techniques are categorized based on the size scale of detection. For observation of the nano-scale biological interactions of nanocarriers, we discuss atomic force microscopy (AFM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). For the micro to macro-scale (in vitro and in vivo) observation, we focus on confocal laser scanning microscopy (CLSM) as well as in vivo imaging systems such as magnetic resonance imaging (MRI), superconducting quantum interference devices (SQUIDs), and IVIS®. Additionally, recently developed combined techniques such as AFM-CLSM, correlative Light and Electron Microscopy (CLEM), and SEM-spectroscopy are also discussed. In this review, we describe how each technique helps elucidate certain physicochemical and biological activities of nanocarriers such as dendrimers, polymers, liposomes, and polymeric/inorganic nanoparticles, thus providing a toolbox for bioengineers, pharmaceutical scientists, biologists, and research clinicians. PMID:20232368

Quantum optics and nano-optics teaching laboratory for the undergraduate curriculum: teaching quantum mechanics and nano-physics with photon counting instrumentation

NASA Astrophysics Data System (ADS)

Lukishova, Svetlana G.

2017-08-01

At the Institute of Optics, University of Rochester (UR), we have adapted to the main challenge (the lack of space in the curriculum) by developing a series of modular 3-hour experiments and 20-min-demonstrations based on technical elective, 4-credit-hour laboratory course "Quantum Optics and Nano-Optics Laboratory" (OPT 253/OPT453/PHY434), that were incorporated into a number of required courses ranging from freshman to senior level. Rochester Monroe Community College (MCC) students also benefited from this facility that was supported by four NSF grants. MCC students carried out two 3-hour labs on photon quantum mechanics at the UR. Since 2006, total 566 students passed through the labs with lab reports submission (including 144 MCC students) and more than 250 students through lab demonstrations. In basic class OPT 253, four teaching labs were prepared on generation and characterization of entangled and single (antibunched) photons demonstrating the laws of quantum mechanics: (1) entanglement and Bell's inequalities, (2) single-photon interference (Young's double slit experiment and Mach-Zehnder interferometer), (3) confocal microscope imaging of single-emitter (colloidal nanocrystal quantum dots and NV-center nanodiamonds) fluorescence within photonic (liquid crystal photonic bandgap microcavities) or plasmonic (gold bowtie nanoantennas) nanostructures, (4) Hanbury Brown and Twiss setup. Fluorescence antibunching from nanoemitters. Students also carried out measurements of nanodiamond topography using atomic force microscopy and prepared photonic bandgap materials from cholesteric liquid crystals. Manuals, student reports, presentations, lecture materials and quizzes, as well as some NSF grants' reports are placed on a website http://www.optics.rochester.edu/workgroups/lukishova/QuantumOpticsLab/ . In 2011 UR hosted 6 professors from different US universities in three-days training of these experiments participating in the Immersion Program of the Advanced

Application of exergetic sustainability index to a nano-scale irreversible Brayton cycle operating with ideal Bose and Fermi gasses

NASA Astrophysics Data System (ADS)

Açıkkalp, Emin; Caner, Necmettin

2015-09-01

In this study, a nano-scale irreversible Brayton cycle operating with quantum gasses including Bose and Fermi gasses is researched. Developments in the nano-technology cause searching the nano-scale machines including thermal systems to be unavoidable. Thermodynamic analysis of a nano-scale irreversible Brayton cycle operating with Bose and Fermi gasses was performed (especially using exergetic sustainability index). In addition, thermodynamic analysis involving classical evaluation parameters such as work output, exergy output, entropy generation, energy and exergy efficiencies were conducted. Results are submitted numerically and finally some useful recommendations were conducted. Some important results are: entropy generation and exergetic sustainability index are affected mostly for Bose gas and power output and exergy output are affected mostly for the Fermi gas by x. At the high temperature conditions, work output and entropy generation have high values comparing with other degeneracy conditions.

Optical phase nanoscopy in red blood cells using low-coherence spectroscopy.

PubMed

Shock, Itay; Barbul, Alexander; Girshovitz, Pinhas; Nevo, Uri; Korenstein, Rafi; Shaked, Natan T

2012-10-01

We propose a low-coherence spectral-domain phase microscopy (SDPM) system for accurate quantitative phase measurements in red blood cells (RBCs) for the prognosis and monitoring of disease conditions that affect the visco-elastic properties of RBCs. Using the system, we performed time-recordings of cell membrane fluctuations, and compared the nano-scale fluctuation dynamics of healthy and glutaraldehyde-treated RBCs. Glutaraldehyde-treated RBCs possess lower amplitudes of fluctuations, reflecting an increased membrane stiffness. To demonstrate the ability of our system to measure fluctuations of lower amplitudes than those measured by the commonly used holographic phase microscopy techniques, we also constructed wide-field digital interferometry (WFDI) system and compared the performances of both systems. Due to its common-path geometry, the optical-path-delay stability of SDPM was found to be less than 0.3 nm in liquid environment, at least three times better than WFDI under the same conditions. In addition, due to the compactness of SDPM and its inexpensive and robust design, the system possesses a high potential for clinical applications.

Femtosecond pulsed laser processing of electronic materials: Fundamentals and micro/nano-scale applications

NASA Astrophysics Data System (ADS)

Choi, Tae-Youl

ultrashort laser pulse accompanied by the pre-pulse induces air breakdown that can be detrimental to materials processing. A time-resolved pump-and-probe experiment provides distinct evidence for the occurrence of an air plasma and air breakdown. This highly nonlinear phenomenon takes place before the commencement of the ablation process, which is traced beyond elapsed time of the order of 10 ps with respect to the ablating pulse. The nonlinear refractive index of the generated air plasma is calculated as a function of electron density. The self-focusing of the main pulse is identified by the third order nonlinear susceptibility. A crystalline silicon sample is subjected to two optically separated ultra-fast laser pulses of full-width-half-maximum (FWHM) duration of about 80 femtoseconds. These pulses are delivered at wavelength, lambda = 800 nm. Femtosecond-resolved imaging pump-and-probe experiments in reflective and Schlieren configurations have been performed to investigate plasma dynamics and shock wave propagation during the sample ablation process. By using a diffractive optical element (DOE) for beam shaping, microchannels were fabricated. A super-long working distance objective lens was used to machine silicon materials in the sub-micrometer scale. As an extension of micro-machining, the finite difference time domain (FDTD) method is used to assess the feasibility of using near-field distribution of laser light. Gold coated films were machined with nano-scale dimensions and characterized with atomic force microscopy (AFM).

Chinese vinegar classification via volatiles using long-optical-path infrared spectroscopy and chemometrics.

PubMed

Dong, D; Zheng, W; Jiao, L; Lang, Y; Zhao, X

2016-03-01

Different brands of Chinese vinegar are similar in appearance, color and aroma, making their discrimination difficult. The compositions and concentrations of the volatiles released from different vinegars vary by raw material and brewing process and thus offer a means to discriminate vinegars. In this study, we enhanced the detection sensitivity of the infrared spectrometer by extending its optical path. We measured the infrared spectra of the volatiles from 5 brands of Chinese vinegar and observed the spectral characteristics corresponding to alcohols, esters, acids, furfural, etc. Different brands of Chinese vinegar had obviously different infrared spectra and could be classified through chemometrics analysis. Furthermore, we established classification models and demonstrated their effectiveness for classifying different brands of vinegar. This study demonstrates that long-optical-path infrared spectroscopy has the ability to discriminate Chinese vinegars with the advantages that it is fast and non-destructive and eliminates the need for sampling. Copyright © 2015 Elsevier Ltd. All rights reserved.

Nano-scale gene delivery systems; current technology, obstacles, and future directions.

PubMed

Garcia-Guerra, Antonio; Dunwell, Thomas L; Trigueros, Sonia

2018-01-07

Within the different applications of nanomedicine currently being developed, nano-gene delivery is appearing as an exciting new technique with the possibility to overcome recognised hurdles and fulfill several biological and medical needs. The central component of all delivery systems is the requirement for the delivery of genetic material into cells, and for them to eventually reside in the nucleus where their desired function will be exposed. However, genetic material does not passively enter cells; thus, a delivery system is necessary. The emerging field of nano-gene delivery exploits the use of new materials and the properties that arise at the nanometre-scale to produce delivery vectors that can effectively deliver genetic material into a variety of different types of cells. The novel physicochemical properties of the new delivery vectors can be used to address the current challenges existing in nucleic acid delivery in vitro and in vivo. While there is a growing interest in nanostructure-based gene delivery, the field is still in its infancy, and there is yet much to discover about nanostructures and their physicochemical properties in a biological context. We carry out an organized and focused search of bibliographic databases. Our results suggest that despite new breakthroughs in nanostructure synthesis and advanced characterization techniques, we still face many barriers in producing highly efficient and non-toxic delivery systems. In this review, we overview the types of systems currently used for clinical and biomedical research applications along with their advantages and disadvantages, as well as discussing barriers that arise from nano-scale interactions with biological material. In conclusion, we hope that by bringing the far reaching multidisciplinary nature of nano-gene delivery to light, new targeted nanotechnology-bases strategies are developed to overcome the major challenges covered in this review. Copyright© Bentham Science Publishers; For

Nano-scaled Pt/Ag/Ni/Au contacts on p-type GaN for low contact resistance and high reflectivity.

PubMed

Kwon, Y W; Ju, I C; Kim, S K; Choi, Y S; Kim, M H; Yoo, S H; Kang, D H; Sung, H K; Shin, K; Ko, C G

2011-07-01

We synthesized the vertical-structured LED (VLED) using nano-scaled Pt between p-type GaN and Ag-based reflector. The metallization scheme on p-type GaN for high reflectance and low was the nano-scaled Pt/Ag/Ni/Au. Nano-scaled Pt (5 A) on Ag/Ni/Au exhibited reasonably high reflectance of 86.2% at the wavelength of 460 nm due to high transmittance of light through nano-scaled Pt (5 A) onto Ag layer. Ohmic behavior of contact metal, Pt/Ag/Ni/Au, to p-type GaN was achieved using surface treatments of p-type GaN prior to the deposition of contact metals and the specific contact resistance was observed with decreasing Pt thickness of 5 A, resulting in 1.5 x 10(-4) ohms cm2. Forward voltages of Pt (5 A)/Ag/Ni contact to p-type GaN showed 4.19 V with the current injection of 350 mA. Output voltages with various thickness of Pt showed the highest value at the smallest thickness of Pt due to its high transmittance of light onto Ag, leading to high reflectance. Our results propose that nano-scaled Pt/Ag/Ni could act as a promising contact metal to p-type GaN for improving the performance of VLEDs.

Enrichment of Glycoproteins using Nano-scale Chelating Con A Monolithic Capillary Chromatography

PubMed Central

Feng, Shun; Yang, Na; Pennathur, Subramaniam; Goodison, Steve; Lubman, David M.

2009-01-01

Immobilized lectin chromatography can be employed for glycoprotein enrichment, but commonly used columns have limitations of yield and resolution. In order to improve efficiency and to make the technique applicable to minimal sample material, we have developed a nano-scale chelating Concanavalin A (Con A) monolithic capillary prepared using GMA-EDMA (glycidyl methacrylate–co-ethylene dimethacrylate) as polymeric support. Con A was immobilized on Cu(II)-charged iminodiacetic acid (IDA) regenerable sorbents by forming a IDA:Cu(II):Con A sandwich affinity structure that has high column capacity as well as stability. When compared with conventional Con A lectin chromatography, the monolithic capillary enabled the better reproducible detection of over double the number of unique N-glycoproteins in human urine samples. Utility for analysis of minimal biological samples was confirmed by the successful elucidation of glycoprotein profiles in mouse urine samples at the microliter scale. The improved efficiency of the nano-scale monolithic capillary will impact the analysis of glycoproteins in complex biological samples, especially where only limited material may be available. PMID:19366252

Sub-10-nm suspended nano-web formation by direct laser writing

NASA Astrophysics Data System (ADS)

Wang, Sihao; Yu, Ye; Liu, Hailong; Lim, Kevin T. P.; Madurai Srinivasan, Bharathi; Zhang, Yong Wei; Yang, Joel K. W.

2018-06-01

A diffraction-limited three-dimensional (3D) direct laser writing (DLW) system based on two-photon polymerization can routinely pattern structures at the 100 nm length scale. Several schemes have been developed to improve the patterning resolution of 3D DLW but often require customized resist formulations or multi-wavelength exposures. Here, we introduce a scheme to produce suspended nano-webs with feature sizes below 10 nm in IP-Dip resist using sub-threshold exposure conditions in a commercial DLW system. The narrowest suspended lines (nano-webs) measured 7 nm in width. Larger ∼20 nm nano-webs were patterned with ∼80% yield at increased laser powers. In addition, closely spaced nano-gaps with a center-to-center distance of 33 nm were produced by patterning vertically displaced suspended lines followed by metal deposition and liftoff. We provide hypotheses and present preliminary results for a mechanism involving the initiation of a percolative path and a strain-induced narrowing in the nano-web formation. Our approach allows selective features to be patterned with dimensions comparable to the sub-10 nm patterning capability of electron-beam lithography (EBL).

NanoSIMS Reveals New Structural and Elemental Signatures of Early Life

NASA Technical Reports Server (NTRS)

Oehler, Dorothy Z.; Mostefaoui, Smail; Meibom, Anders; Selo, Madeleine; Robert, Francois; McKay, David S.

2006-01-01

The young technology of NanoSIMS is unlocking new information from organic matter in ancient sediments. We have used this technique to characterize sub-micron scale element composition of Proterozoic organics that are clearly biogenic as a guide for interpreting problematic structures in terrestrial or extraterrestrial samples. We used the NanoSIMS 50 of the National Museum of Natural History in Paris to map carbon, nitrogen (as CN), and sulfur in organic structures from the approximately 0.8 Ga Bitter Springs Formation. We analyzed spheroidal and filamentous microfossils as well as organic laminae that appeared amorphous by optical and scanning electron microscopy. In clear-cut microfossils, a coincidence between optical images and NanoSIMS element maps suggests a biological origin for the mapped carbon, sulfur, and nitrogen; this conclusion is supported by high resolution NanoSIMS maps showing identical spatial distributions of C, CN and S. High resolution images also demonstrate distinctive nano structure of the filaments and spheroids. In the amorphous laminae, NanoSIMS reveals morphologies reminiscent of compressed microfossils. Distinct CN/C ratios of the spheroids, filaments, and laminae may reflect their biological precursors (cell walls, cyanobacterial sheaths, and microbial communities/biofilms, respectively). Similar amorphous laminae comprise a preponderance of the organic matter in many Precambrian deposits. Thus it is possible that NanoSIMS will provide fresh insight into a large body of previously uninterpretable material. Additionally, NanoSIMS analysis may establish new biosignatures that will be helpful for assessing the origin and biogenicity of controversial Archean structures and any organic materials that may occur in Martian or other extraterrestrial samples.

Compound focusing mirror and X-ray waveguide optics for coherent imaging and nano-diffraction.

PubMed

Salditt, Tim; Osterhoff, Markus; Krenkel, Martin; Wilke, Robin N; Priebe, Marius; Bartels, Matthias; Kalbfleisch, Sebastian; Sprung, Michael

2015-07-01

A compound optical system for coherent focusing and imaging at the nanoscale is reported, realised by high-gain fixed-curvature elliptical mirrors in combination with X-ray waveguide optics or different cleaning apertures. The key optical concepts are illustrated, as implemented at the Göttingen Instrument for Nano-Imaging with X-rays (GINIX), installed at the P10 coherence beamline of the PETRA III storage ring at DESY, Hamburg, and examples for typical applications in biological imaging are given. Characteristic beam configurations with the recently achieved values are also described, meeting the different requirements of the applications, such as spot size, coherence or bandwidth. The emphasis of this work is on the different beam shaping, filtering and characterization methods.

Laser Scanning Holographic Lithography for Flexible 3D Fabrication of Multi-Scale Integrated Nano-structures and Optical Biosensors

PubMed Central

Yuan, Liang (Leon); Herman, Peter R.

2016-01-01

Three-dimensional (3D) periodic nanostructures underpin a promising research direction on the frontiers of nanoscience and technology to generate advanced materials for exploiting novel photonic crystal (PC) and nanofluidic functionalities. However, formation of uniform and defect-free 3D periodic structures over large areas that can further integrate into multifunctional devices has remained a major challenge. Here, we introduce a laser scanning holographic method for 3D exposure in thick photoresist that combines the unique advantages of large area 3D holographic interference lithography (HIL) with the flexible patterning of laser direct writing to form both micro- and nano-structures in a single exposure step. Phase mask interference patterns accumulated over multiple overlapping scans are shown to stitch seamlessly and form uniform 3D nanostructure with beam size scaled to small 200 μm diameter. In this way, laser scanning is presented as a facile means to embed 3D PC structure within microfluidic channels for integration into an optofluidic lab-on-chip, demonstrating a new laser HIL writing approach for creating multi-scale integrated microsystems. PMID:26922872

Mass production of polymer nano-wires filled with metal nano-particles.

PubMed

Lomadze, Nino; Kopyshev, Alexey; Bargheer, Matias; Wollgarten, Markus; Santer, Svetlana

2017-08-17

Despite the ongoing progress in nanotechnology and its applications, the development of strategies for connecting nano-scale systems to micro- or macroscale elements is hampered by the lack of structural components that have both, nano- and macroscale dimensions. The production of nano-scale wires with macroscale length is one of the most interesting challenges here. There are a lot of strategies to fabricate long nanoscopic stripes made of metals, polymers or ceramics but none is suitable for mass production of ordered and dense arrangements of wires at large numbers. In this paper, we report on a technique for producing arrays of ordered, flexible and free-standing polymer nano-wires filled with different types of nano-particles. The process utilizes the strong response of photosensitive polymer brushes to irradiation with UV-interference patterns, resulting in a substantial mass redistribution of the polymer material along with local rupturing of polymer chains. The chains can wind up in wires of nano-scale thickness and a length of up to several centimeters. When dispersing nano-particles within the film, the final arrangement is similar to a core-shell geometry with mainly nano-particles found in the core region and the polymer forming a dielectric jacket.

Optical Manipulation along Optical Axis with Polarization Sensitive Meta-lens.

PubMed

Markovich, Hen; Shishkin, Ivan; Hendler, Netta; Ginzburg, Pavel

2018-06-27

The ability to manipulate small objects with focused laser beams opens a broad spectrum of opportunities in fundamental and applied studies, where a precise control over mechanical path and stability is required. While conventional optical tweezers are based on bulky diffractive optical elements, developing compact integrable within a fluid cell trapping devices is highly demanded. Here, plasmonic polarization sensitive metasurface-based lens, embedded within a fluid, is demonstrated to provide several stable trapping centers along the optical axis. The position of a particle is controlled with the polarization of the incident light, interacting with plasmonic nanoscale patch antennas, organized within overlapping Fresnel zones of the lens. While standard diffractive optical elements face challenges to trap objects in lateral direction outside the depth of focus, bi-focal Fresnel meta-lens demonstrates the capability to manipulate a bead along 4 micrometers line. Additional fluorescent module, incorporated within the optical trapping setup, was implemented and enabled accurate mapping of optical potential via a particle tracking algorithm. Auxiliary micro- and nano- structures, integrated within fluidic devices, provide numerous opportunities to achieve flexible optomechanical manipulation, including, transport, trapping and sorting, which are highly demanded in lab-on-a-chip applications and many others.

Electron transport in nano-scaled piezoelectronic devices

NASA Astrophysics Data System (ADS)

Jiang, Zhengping; Kuroda, Marcelo A.; Tan, Yaohua; Newns, Dennis M.; Povolotskyi, Michael; Boykin, Timothy B.; Kubis, Tillmann; Klimeck, Gerhard; Martyna, Glenn J.

2013-05-01

The Piezoelectronic Transistor (PET) has been proposed as a post-CMOS device for fast, low-power switching. In this device, the piezoresistive channel is metalized via the expansion of a relaxor piezoelectric element to turn the device on. The mixed-valence compound SmSe is a good choice of PET channel material because of its isostructural pressure-induced continuous metal insulator transition, which is well characterized in bulk single crystals. Prediction and optimization of the performance of a realistic, nano-scaled PET based on SmSe requires the understanding of quantum confinement, tunneling, and the effect of metal interface. In this work, a computationally efficient empirical tight binding (ETB) model is developed for SmSe to study quantum transport in these systems and the scaling limit of PET channel lengths. Modulation of the SmSe band gap under pressure is successfully captured by ETB, and ballistic conductance shows orders of magnitude change under hydrostatic strain, supporting operability of the PET device at nanoscale.

Generation of elliptical and circular vector hollow beams with different polarizations by a Mach-Zehnder-type optical path

NASA Astrophysics Data System (ADS)

Wang, Zhizhang; Pei, Chunying; Xia, Meng; Yin, Yaling; Xia, Yong; Yin, Jianping

2018-01-01

We present an experimental approach to convert linearly polarized Gaussian beams into elliptical and circular vector hollow beams (VHBs) with different polarization states. The scheme employed is based on a Mach-Zehnder-type optical path combined with a reflective spatial light modulator (SLM) in each path. The resulting VHBs have radial, azimuthal, and other polarization states. Our studies also show that the size of the generated VHBs remains constant during the propagation in free space over a certain distance, and can be controlled by the axial ratio of the SLM’s binary phase plate. These studies deliver great optical parameters and hold promising applications in the fields of optical trapping and manipulation of particles.

Nano-scaled graphene platelets with a high length-to-width aspect ratio

DOEpatents

Zhamu, Aruna; Guo, Jiusheng; Jang, Bor Z.

2010-09-07

This invention provides a nano-scaled graphene platelet (NGP) having a thickness no greater than 100 nm and a length-to-width ratio no less than 3 (preferably greater than 10). The NGP with a high length-to-width ratio can be prepared by using a method comprising (a) intercalating a carbon fiber or graphite fiber with an intercalate to form an intercalated fiber; (b) exfoliating the intercalated fiber to obtain an exfoliated fiber comprising graphene sheets or flakes; and (c) separating the graphene sheets or flakes to obtain nano-scaled graphene platelets. The invention also provides a nanocomposite material comprising an NGP with a high length-to-width ratio. Such a nanocomposite can become electrically conductive with a small weight fraction of NGPs. Conductive composites are particularly useful for shielding of sensitive electronic equipment against electromagnetic interference (EMI) or radio frequency interference (RFI), and for electrostatic charge dissipation.

Ultrafast optics. Ultrafast optical control by few photons in engineered fiber.

PubMed

Nissim, R; Pejkic, A; Myslivets, E; Kuo, B P; Alic, N; Radic, S

2014-07-25

Fast control of a strong optical beam by a few photons is an outstanding challenge that limits the performance of quantum sensors and optical processing devices. We report that a fast and efficient optical gate can be realized in an optical fiber that has been engineered with molecular-scale accuracy. Highly efficient, distributed phase-matched photon-photon interaction was achieved in the fiber with locally controlled, nanometer-scale core variations. A three-photon input was used to manipulate a Watt-scale beam at a speed exceeding 500 gigahertz. In addition to very fast beam control, the results provide a path to developing a new class of sensitive receivers capable of operating at very high rates. Copyright © 2014, American Association for the Advancement of Science.

Optical Nano Antennas: State of the Art, Scope and Challenges as a Biosensor Along with Human Exposure to Nano-Toxicology

PubMed Central

Kausar, Abu Sulaiman Mohammad Zahid; Reza, Ahmed Wasif; Latef, Tarik Abdul; Ullah, Mohammad Habib; Karim, Mohammad Ershadul

2015-01-01

The concept of optical antennas in physical optics is still evolving. Like the antennas used in the radio frequency (RF) regime, the aspiration of optical antennas is to localize the free propagating radiation energy, and vice versa. For this purpose, optical antennas utilize the distinctive properties of metal nanostructures, which are strong plasmonic coupling elements at the optical regime. The concept of optical antennas is being advanced technologically and they are projected to be substitute devices for detection in the millimeter, infrared, and visible regimes. At present, their potential benefits in light detection, which include polarization dependency, tunability, and quick response times have been successfully demonstrated. Optical antennas also can be seen as directionally responsive elements for point detectors. This review provides an overview of the historical background of the topic, along with the basic concepts and parameters of optical antennas. One of the major parts of this review covers the use of optical antennas in biosensing, presenting biosensing applications with a broad description using different types of data. We have also mentioned the basic challenges in the path of the universal use of optical biosensors, where we have also discussed some legal matters. PMID:25884787

Nano-Engineered Biomimetic Optical Sensors for Glucose Monitoring in Diabetes.

PubMed

Rauf, Sajid; Hayat Nawaz, Muhammad Azhar; Badea, Mihaela; Marty, Jean Louis; Hayat, Akhtar

2016-11-17

Diabetes is a rapidly growing disease that can be monitored at an individual level by controlling the blood glucose level, hence minimizing the negative impact of the disease. Significant research efforts have been focused on the design of novel and improved technologies to overcome the limitations of existing glucose analysis methods. In this context, nanotechnology has enabled the diagnosis at the single cell and molecular level with the possibility of incorporation in advanced molecular diagnostic biochips. Recent years have witnessed the exploration and synthesis of various types of nanomaterials with enzyme-like properties, with their subsequent integration into the design of biomimetic optical sensors for glucose monitoring. This review paper will provide insights on the type, nature and synthesis of different biomimetic nanomaterials. Moreover, recent developments in the integration of these nanomaterials for optical glucose biosensing will be highlighted, with a final discussion on the challenges that must be addressed for successful implementation of these nano-devices in the clinical applications is presented.

Nano-Engineered Biomimetic Optical Sensors for Glucose Monitoring in Diabetes

PubMed Central

Rauf, Sajid; Hayat Nawaz, Muhammad Azhar; Badea, Mihaela; Marty, Jean Louis; Hayat, Akhtar

2016-01-01

Diabetes is a rapidly growing disease that can be monitored at an individual level by controlling the blood glucose level, hence minimizing the negative impact of the disease. Significant research efforts have been focused on the design of novel and improved technologies to overcome the limitations of existing glucose analysis methods. In this context, nanotechnology has enabled the diagnosis at the single cell and molecular level with the possibility of incorporation in advanced molecular diagnostic biochips. Recent years have witnessed the exploration and synthesis of various types of nanomaterials with enzyme-like properties, with their subsequent integration into the design of biomimetic optical sensors for glucose monitoring. This review paper will provide insights on the type, nature and synthesis of different biomimetic nanomaterials. Moreover, recent developments in the integration of these nanomaterials for optical glucose biosensing will be highlighted, with a final discussion on the challenges that must be addressed for successful implementation of these nano-devices in the clinical applications is presented. PMID:27869658

MapMaker and PathTracer for tracking carbon in genome-scale metabolic models

PubMed Central

Tervo, Christopher J.; Reed, Jennifer L.

2016-01-01

Constraint-based reconstruction and analysis (COBRA) modeling results can be difficult to interpret given the large numbers of reactions in genome-scale models. While paths in metabolic networks can be found, existing methods are not easily combined with constraint-based approaches. To address this limitation, two tools (MapMaker and PathTracer) were developed to find paths (including cycles) between metabolites, where each step transfers carbon from reactant to product. MapMaker predicts carbon transfer maps (CTMs) between metabolites using only information on molecular formulae and reaction stoichiometry, effectively determining which reactants and products share carbon atoms. MapMaker correctly assigned CTMs for over 97% of the 2,251 reactions in an Escherichia coli metabolic model (iJO1366). Using CTMs as inputs, PathTracer finds paths between two metabolites. PathTracer was applied to iJO1366 to investigate the importance of using CTMs and COBRA constraints when enumerating paths, to find active and high flux paths in flux balance analysis (FBA) solutions, to identify paths for putrescine utilization, and to elucidate a potential CO2 fixation pathway in E. coli. These results illustrate how MapMaker and PathTracer can be used in combination with constraint-based models to identify feasible, active, and high flux paths between metabolites. PMID:26771089

Wafer-scale micro-optics fabrication

NASA Astrophysics Data System (ADS)

Voelkel, Reinhard

2012-07-01

Micro-optics is an indispensable key enabling technology for many products and applications today. Probably the most prestigious examples are the diffractive light shaping elements used in high-end DUV lithography steppers. Highly-efficient refractive and diffractive micro-optical elements are used for precise beam and pupil shaping. Micro-optics had a major impact on the reduction of aberrations and diffraction effects in projection lithography, allowing a resolution enhancement from 250 nm to 45 nm within the past decade. Micro-optics also plays a decisive role in medical devices (endoscopes, ophthalmology), in all laser-based devices and fiber communication networks, bringing high-speed internet to our homes. Even our modern smart phones contain a variety of micro-optical elements. For example, LED flash light shaping elements, the secondary camera, ambient light and proximity sensors. Wherever light is involved, micro-optics offers the chance to further miniaturize a device, to improve its performance, or to reduce manufacturing and packaging costs. Wafer-scale micro-optics fabrication is based on technology established by the semiconductor industry. Thousands of components are fabricated in parallel on a wafer. This review paper recapitulates major steps and inventions in wafer-scale micro-optics technology. The state-of-the-art of fabrication, testing and packaging technology is summarized.

Common path ball lens probe for optical coherence tomography (Conference Presentation)

NASA Astrophysics Data System (ADS)

Singh, Kanwarpal; Yamada, Daisuke; Tearney, Guillermo J.

2016-02-01

Background: Common path probes are highly desirable for optical coherence tomography (OCT) as they reduce system complexity and cost. In this work we report an all-fiber common path side viewing monolithic probe for coronary artery imaging. Methods: Our common path probe was designed for spectrometer based Fourier domain OCT at 1310 nm wavelength. Light from the fiber expands in the coreless fiber region and then focussed by the ball lens. Reflection from ball lens-air interface served as reference signal. The monolithic ball lens probe was assembled within a 560 µmouter diameter drive shaft which was attached to a rotary junction. The drive shaft was placed inside an outer, transparent sheath of 800 µm diameter. Results: With a source input power of 25 mW, we could achieve sensitivity of 100.5 dB. The axial resolution of the system was found to be 15.6 µm in air and the lateral resolution (full width half maximum) was approximately 49 µm. As proof of principal, images of skin acquired using this probe demonstrated clear visualization of the stratum corneum, epidermis, and papillary dermis, along with sweat ducts. Conclusion: In this work we have demonstrated a monolithic, ball lens common, path probe for OCT imaging. The designed ball lens probe is easy to fabricate using a laser splicer. Based on the features and capability of common path probes to provide a simpler solution for OCT, we believe that this development will be an important enhancement for certain types of catheters.

45 Km Horizontal Path Optical Link Experiment

NASA Technical Reports Server (NTRS)

Biswas, A.; Ceniceros, J.; Novak, M.; Jeganathan, M.; Portillo, A.; Erickson, D.; Depew, J.; Sanii, B.; Lesh, J. R.

2000-01-01

Mountain-top to mountain-top optical link experiments have been initiated at JPL, in order to perform a systems level evaluation of optical communications. Progress made so far is reported. ne NASA, JPL developed optical communications demonstrator (OCD) is used to transmit a laser signal from Strawberry Peak (SP), located in the San Bernadino mountains of California. This laser beam is received by a 0.6 m aperture telescope at JPL's Table Mountain Facility (TMF), located in Wrightwood, California. The optical link is bi-directional with the TMF telescope transmitting a continuous 4-wave (cw) 780 run beacon and the OCD sending back a 840 nm, 100 - 500 Mbps pseudo noise (PN) modulated, laser beam. The optical link path is at an average altitude of 2 km above sea level, covers a range of 46.8 km and provides an atmospheric channel equivalent to approx. 4 air masses. Average received power measured at either end fall well within the uncertainties predicted by link analysis. The reduction in normalized intensity variance (sigma(sup 2, sub I)) for the 4-beam beacon, compared to each individual beam, at SP, was from approx. 0.68 to 0.22. With some allowance for intra-beam mis-alignment, this is consistent with incoherent averaging. The sigma(sup2, sub I) measured at TMF approx. 0.43 +/- 0.22 exceeded the expected aperture averaged value of less than 0.1, probably because of beam wander. The focused spot sizes of approx. 162 +/- 6 microns at the TMF Coude and approx. 64 +/- 3 microns on the OCD compare to the predicted size range of 52 - 172 microns and 57 - 93 microns, respectively. This is consistent with 4 - 5 arcsec of atmospheric "seeing". The preliminary evaluation of OCD's fine tracking indicates that the uncompensated tracking error is approx. 3.3 micro rad compared to approx. 1.7 micro rad observed in the laboratory. Fine tracking performance was intermittent, primarily due to beacon fades on the OCD tracking sensor. The best bit error rates observed while

Fabrication of micro/nano hierarchical structures with analysis on the surface mechanics

NASA Astrophysics Data System (ADS)

Jheng, Yu-Sheng; Lee, Yeeu-Chang

2016-10-01

Biomimicry refers to the imitation of mechanisms and features found in living creatures using artificial methods. This study used optical lithography, colloidal lithography, and dry etching to mimic the micro/nano hierarchical structures covering the soles of gecko feet. We measured the static contact angle and contact angle hysteresis to reveal the behavior of liquid drops on the hierarchical structures. Pulling tests were also performed to measure the resistance of movement between the hierarchical structures and a testing plate. Our results reveal that hierarchical structures at the micro-/nano-scale are considerably hydrophobic, they provide good flow characteristics, and they generate more contact force than do surfaces with micro-scale cylindrical structures.

Synchronized femtosecond laser pulse switching system based nano-patterning technology

NASA Astrophysics Data System (ADS)

Sohn, Ik-Bu; Choi, Hun-Kook; Yoo, Dongyoon; Noh, Young-Chul; Sung, Jae-Hee; Lee, Seong-Ku; Ahsan, Md. Shamim; Lee, Ho

2017-07-01

This paper demonstrates the design and development of a synchronized femtosecond laser pulse switching system and its applications in nano-patterning of transparent materials. Due to synchronization, we are able to control the location of each irradiated laser pulse in any kind of substrate. The control over the scanning speed and scanning step of the laser beam enables us to pattern periodic micro/nano-metric holes, voids, and/or lines in various materials. Using the synchronized laser system, we pattern synchronized nano-holes on the surface of and inside various transparent materials including fused silica glass and polymethyl methacrylate to replicate any image or pattern on the surface of or inside (transparent) materials. We also investigate the application areas of the proposed synchronized femtosecond laser pulse switching system in a diverse field of science and technology, especially in optical memory, color marking, and synchronized micro/nano-scale patterning of materials.

Fluorophore-NanoLuc BRET Reporters Enable Sensitive In Vivo Optical Imaging and Flow Cytometry for Monitoring Tumorigenesis

PubMed Central

Schaub, Franz X; Reza, Md Shamim; Flaveny, Colin A; Li, Weimin; Musicant, Adele M; Hoxha, Sany; Guo, Min; Cleveland, John L; Amelio, Antonio L

2015-01-01

Fluorescent proteins are widely used to study molecular and cellular events, yet this traditionally relies on delivery of excitation light, which can trigger autofluorescence, photoxicity, and photobleaching, impairing their use in vivo. Accordingly, chemiluminescent light sources such as those generated by luciferases have emerged, as they do not require excitation light. However, current luciferase reporters lack the brightness needed to visualize events in deep tissues. We report the creation of chimeric eGFP-NanoLuc (GpNLuc) and LSSmOrange-NanoLuc (OgNLuc) fusion reporter proteins coined LumiFluors, which combine the benefits of eGFP or LSSmOrange fluorescent proteins with the bright, glow-type bioluminescent light generated by an enhanced small luciferase subunit (NanoLuc) of the deep sea shrimp Oplophorus gracilirostris. The intramolecular bioluminescence resonance energy transfer (BRET) that occurs between NanoLuc and the fused fluorophore generates the brightest bioluminescent signal known to date, including improved intensity, sensitivity and durable spectral properties, thereby dramatically reducing image acquisition times and permitting highly sensitive in vivo imaging. Notably, the self-illuminating and bi-functional nature of these LumiFluor reporters enables greatly improved spatio-temporal monitoring of very small numbers of tumor cells via in vivo optical imaging and also allows the isolation and analyses of single cells by flow cytometry. Thus, LumiFluor reporters are inexpensive, robust, non-invasive tools that allow for markedly improved in vivo optical imaging of tumorigenic processes. PMID:26424696

Nuclear Reactions in Micro/Nano-Scale Metal Particles

NASA Astrophysics Data System (ADS)

Kim, Y. E.

2013-03-01

Low-energy nuclear reactions in micro/nano-scale metal particles are described based on the theory of Bose-Einstein condensation nuclear fusion (BECNF). The BECNF theory is based on a single basic assumption capable of explaining the observed LENR phenomena; deuterons in metals undergo Bose-Einstein condensation. The BECNF theory is also a quantitative predictive physical theory. Experimental tests of the basic assumption and theoretical predictions are proposed. Potential application to energy generation by ignition at low temperatures is described. Generalized theory of BECNF is used to carry out theoretical analyses of recently reported experimental results for hydrogen-nickel system.

Design of differential optical absorption spectroscopy long-path telescopes based on fiber optics.

PubMed

Merten, André; Tschritter, Jens; Platt, Ulrich

2011-02-10

We present a new design principle of telescopes for use in the spectral investigation of the atmosphere and the detection of atmospheric trace gases with the long-path differential optical absorption spectroscopy (DOAS) technique. A combination of emitting and receiving fibers in a single bundle replaces the commonly used coaxial-Newton-type combination of receiving and transmitting telescope. This very simplified setup offers a higher light throughput and simpler adjustment and allows smaller instruments, which are easier to handle and more portable. The higher transmittance was verified by ray-tracing calculations, which result in a theoretical factor threefold improvement in signal intensity compared with the old setup. In practice, due to the easier alignment and higher stability, up to factor of 10 higher signal intensities were found. In addition, the use of a fiber optic light source provides a better spectral characterization of the light source, which results in a lower detection limit for trace gases studied with this instrument. This new design will greatly enhance the usability and the range of applications of active DOAS instruments.

Stabilizing the body centered cubic crystal in titanium alloys by a nano-scale concentration modulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, H. L.; Shah, S. A. A.; Hao, Y. L.

It is well-known that the body centered cubic (bcc) crystal in titanium alloys reaches its stability limit as the electron-to-atom (e/a) ratio of the alloy drops down to ~4.24. This critical value, however, is much higher than that of a multifunctional bcc type alloy (e/a = 4.15). Here we demonstrate that a nano-scale concentration modulation created by spinodal decomposition is what stabilizes the bcc crystal of the alloy. Aided by such a nano-scale concentration heterogeneity, unexpected properties from its chemically homogeneous counterpart are obtained. This provides a new strategy to design functional titanium alloys by tuning the spinodal decomposition.

Arc-evaporated carbon films: optical properties and electron mean free paths

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, M.W.; Arakawa, E.T.; Dolfini, S.M.

1984-01-01

This paper describes briefly a method which can be used to calculate inelastic mean free paths for electrons with energies in the range of interest for the interpretation of surface phenomena. This method requires a knowledge of the optical properties of the material for the photon energies associated with the oscillator strength of the valence electrons. However, in general it is easier to obtain accurate values of the required properties than it is to measure the electron attenuation lengths in the energy region of interest. This technique, demonstrated here for arc-evaporated carbon, can be used for any material for whichmore » the optical properties can be measured over essentially the whole energy range corresponding to the valence electron response.« less

Optical nano artifact metrics using silicon random nanostructures

NASA Astrophysics Data System (ADS)

Matsumoto, Tsutomu; Yoshida, Naoki; Nishio, Shumpei; Hoga, Morihisa; Ohyagi, Yasuyuki; Tate, Naoya; Naruse, Makoto

2016-08-01

Nano-artifact metrics exploit unique physical attributes of nanostructured matter for authentication and clone resistance, which is vitally important in the age of Internet-of-Things where securing identities is critical. However, expensive and huge experimental apparatuses, such as scanning electron microscopy, have been required in the former studies. Herein, we demonstrate an optical approach to characterise the nanoscale-precision signatures of silicon random structures towards realising low-cost and high-value information security technology. Unique and versatile silicon nanostructures are generated via resist collapse phenomena, which contains dimensions that are well below the diffraction limit of light. We exploit the nanoscale precision ability of confocal laser microscopy in the height dimension; our experimental results demonstrate that the vertical precision of measurement is essential in satisfying the performances required for artifact metrics. Furthermore, by using state-of-the-art nanostructuring technology, we experimentally fabricate clones from the genuine devices. We demonstrate that the statistical properties of the genuine and clone devices are successfully exploited, showing that the liveness-detection-type approach, which is widely deployed in biometrics, is valid in artificially-constructed solid-state nanostructures. These findings pave the way for reasonable and yet sufficiently secure novel principles for information security based on silicon random nanostructures and optical technologies.

Reversible nano-lithography for commercial approaches

NASA Astrophysics Data System (ADS)

Park, Jae Hong; Jang, Hyun Ik; Kim, Woo Choong; Yun, Hae S.; Park, Jun Yong; Jeon, Seok Woo; Kim, Hee Yeoun; Ahn, Chi Won

2016-04-01

The methodology suggested in this research provides the great possibility of creating nanostructures composed of various materials, such as soft polymer, hard polymer, and metal, as well as Si. Such nanostructures are required for a vast range of optical and display devices, photonic components, physical devices, energy devices including electrodes of secondary batteries, fuel cells, solar cells, and energy harvesters, biological devices including biochips, biomimetic or biosimilar structured devices, and mechanical devices including micro- or nano-scale sensors and actuators.

Plasmonic non-concentric nanorings array as an unidirectional nano-optical conveyor belt actuated by polarization rotation.

PubMed

Jiang, Min; Wang, Guanghui; Jiao, Wenxiang; Ying, Zhoufeng; Zou, Ningmu; Ho, Ho-Pui; Sun, Tianyu; Zhang, Xuping

2017-01-15

We report a nano-optical conveyor belt containing an array of gold plasmonic non-concentric nanorings (PNNRs) for the realization of trapping and unidirectional transportation of nanoparticles through rotating the polarization of an excitation beam. The location of hot spots within an asymmetric plasmonic nanostructure is polarization dependent, thus making it possible to manipulate a trapped target by rotating the incident polarization state. In the case of PNNR, the two poles have highly unbalanced trap potential. This greatly enhances the chance of transferring trapped particles between adjacent PNNRs in a given direction through rotating the polarization. As confirmed by three-dimensional finite-difference time-domain analysis, an array of PNNRs forms an unidirectional nano-optical conveyor belt, which delivers target nanoparticles or biomolecules over a long distance with nanometer accuracy. With the capacity to trap and to transfer, our design offers a versatile scheme for conducting mechanical sample manipulation in many on-chip optofluidic applications.

Mechano-micro/nano systems

NASA Astrophysics Data System (ADS)

Horie, Mikio

2004-10-01

In recent years, the researches about Micro/Nano Systems are down actively in the bio-medical research fields, DNA research fields, chemical analysis systems fields, etc. In the results, a new materials and new functions in the systems are developed. In this invited paper, Mechano-Micro/Nano Systems, especially, motion systems are introduced. First, the research activities concerning the Mechano-Micro/Nano Systems in the world(MST2003, MEMS2003 and MEMS2004) and in Japan(Researech Projects on Nanotechnology and Materials in Ministry of Education, Culture, Sports, Science and Technology) are shown. Secondary, my research activities are introduced. As my research activities, (1) a comb-drive static actuator for the motion convert mechanisms, (2) a micro-nano fabrication method by use of FAB(Fast Atom Beam) machines, (3) a micro optical mirror manipulator for inputs-outputs optical switches, (4) a miniature pantograph mechanism with large-deflective hinges and links made of plastics are discussed and their performances are explained.

Nano-imprint gold grating as refractive index sensor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kumari, Sudha; Mohapatra, Saswat; Moirangthem, Rakesh S.

Large scale of fabrication of plasmonic nanostructures has been a challenging task due to time consuming process and requirement of expensive nanofabrication tools such as electron beam lithography system, focused ion beam system, and extreme UV photolithography system. Here, we present a cost-effective fabrication technique so called soft nanoimprinting to fabricate nanostructures on the larger sample area. In our fabrication process, a commercially available optical DVD disc was used as a template which was imprinted on a polymer glass substrate to prepare 1D polymer nano-grating. A homemade nanoimprinting setup was used in this fabrication process. Further, a label-free refractive indexmore » sensor was developed by utilizing the properties of surface plasmon resonance (SPR) of a gold coated 1D polymer nano-grating. Refractive index sensing was tested by exposing different solutions of glycerol-water mixture on the surface of gold nano-grating. The calculated bulk refractive index sensitivity was found to be 751nm/RIU. We believed that our proposed SPR sensor could be a promising candidate for developing low-cost refractive index sensor with high sensitivity on a large scale.« less

Tribological Properties of CrAlN and TiN Coatings Tested in Nano- and Micro-scale Laboratory Wear Tests

NASA Astrophysics Data System (ADS)

Hong, Ling; Bian, Guangdong; Hu, Shugen; Wang, Linlin; Dacosta, Herbert

2015-07-01

We investigated the tribological properties of CrAlN and TiN coatings produced by electron beam plasma-assisted physical vapor deposition by nano- and micro-scale wear tests. For comparison, we also conducted nano-indentation, nano-scanning wear tests, and pin-on-disk tribotests on uncoated M2 steel. The results indicate that, after nano-scale sliding tests against diamond indenter and pin-on-disk tests against ceramic alumina counterface pins, the CrAlN coating presents superior abrasive wear resistance compared to the TiN-coated and uncoated M2 steel samples. Against aluminum counterface, aluminum is more prone to attach on the CrAlN coating surface compared to TiN coating, but no apparent adhesive wear was observed, which has occurred on the TiN coating.

The efficiency of parameter estimation of latent path analysis using summated rating scale (SRS) and method of successive interval (MSI) for transformation of score to scale

NASA Astrophysics Data System (ADS)

Solimun, Fernandes, Adji Achmad Rinaldo; Arisoesilaningsih, Endang

2017-12-01

Research in various fields generally investigates systems and involves latent variables. One method to analyze the model representing the system is path analysis. The data of latent variables measured using questionnaires by applying attitude scale model yields data in the form of score, before analyzed should be transformation so that it becomes data of scale. Path coefficient, is parameter estimator, calculated from scale data using method of successive interval (MSI) and summated rating scale (SRS). In this research will be identifying which data transformation method is better. Path coefficients have smaller varieties are said to be more efficient. The transformation method that produces scaled data and used in path analysis capable of producing path coefficients (parameter estimators) with smaller varieties is said to be better. The result of analysis using real data shows that on the influence of Attitude variable to Intention Entrepreneurship, has relative efficiency (ER) = 1, where it shows that the result of analysis using data transformation of MSI and SRS as efficient. On the other hand, for simulation data, at high correlation between items (0.7-0.9), MSI method is more efficient 1.3 times better than SRS method.

Enhanced optical and electrochemical properties of polyaniline/cobalt oxide nano composite

NASA Astrophysics Data System (ADS)

Niranjana, M.; Yesappa, L.; Ashokkumar, S. P.; Vijeth, H.; Basappa, M.; Devendrappa, H.

2018-05-01

Polyaniline and its composites at different wt. % of Cobalt oxide nano (PDC1, PDC2 and PDC5) were prepared by in-situ chemical reaction method The optical property was carried out using UV-Vis. Absorption Spectroscopy. The electrochemical property like cyclic voltammetry and galvonostatic charging-discharging was carried out for PANI and PDC nanocomposite electrode materials. A specific capacitance of 212.08 F/g and 336.41 F/g with scan rates 100 and 200 mV/s at 0.4 A/g current density respectively. These results are suggesting PDC composite is a prominent candidate for supercapacitor properties applications.

Nano Liquid Crystal Droplet Impact on Solid Surfaces

NASA Astrophysics Data System (ADS)

Zhang, Rui; de Pablo, Juan; dePablo Team

2015-03-01

Liquid droplet impaction on solid surfaces is an important problem with a wide range of applications in everyday life. Liquid crystals (LCs) are anisotropic liquids whose internal structure gives rise to rich optical and morphological phenomena. In this work we study the liquid crystal droplet impaction on solid surfaces by molecular dynamics simulations. We employ a widely used Gay-Berne model to describe the elongated liquid crystal molecules and their interactions. Our work shows that, in contrast to isotropic liquids, drop deformation is symmetric unless an instability kicks in, in which case a nano scale liquid crystal droplet exhibits distinct anisotropic spreading modes that do not occur in simple liquids. The drop prefers spreading along the low viscosity direction, but inertia can in some cases overcome that bias. The effects of the director field of the droplet, preferred anchoring direction and the anchoring strength of the wall are investigated. Large scale (0.1 micron) simulations are performed to connect our nano scale results to the experiments. Our studies indicate that LCs could provide an interesting alternative for development of next-generation printing inks.

Scaling properties of ballistic nano-transistors

PubMed Central

2011-01-01

Recently, we have suggested a scale-invariant model for a nano-transistor. In agreement with experiments a close-to-linear thresh-old trace was found in the calculated ID - VD-traces separating the regimes of classically allowed transport and tunneling transport. In this conference contribution, the relevant physical quantities in our model and its range of applicability are discussed in more detail. Extending the temperature range of our studies it is shown that a close-to-linear thresh-old trace results at room temperatures as well. In qualitative agreement with the experiments the ID - VG-traces for small drain voltages show thermally activated transport below the threshold gate voltage. In contrast, at large drain voltages the gate-voltage dependence is weaker. As can be expected in our relatively simple model, the theoretical drain current is larger than the experimental one by a little less than a decade. PMID:21711899

Developing Sensitive and Selective Nanosensors: A Single Molecule - Multiple Excitation Source Approach. Altairnano Lithium Ion Nano-scaled Titanate Oxide Cell and Module Abuse Testing

DTIC Science & Technology

2012-03-13

Source Approach Part II. Altairnano Lithium Ion Nano-scaled Titanate Oxide Cell and Module Abuse Testing 14. ABSTRACT 16. SECURITY CLASSIFICATION OF...Lithium Ion Nano-scaled Titanate Oxide Cell and Module Abuse Testing Report Title ABSTRACT This final report for Contract W911NF-09-C-0135 transmits the...prototype development. The second (Part II.) is "Altairnano Lithium Ion Nano-scaled Titanate Oxide Cell and Module Abuse Test Report". The

Angular dependence of dose sensitivity of nanoDot optically stimulated luminescent dosimeters in different radiation geometries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jursinic, Paul A., E-mail: pjursinic@wmcc.org

2015-10-15

Purpose: A type of in vivo dosimeter, an optically stimulated luminescent dosimeter, OSLD, may have dose sensitivity that depends on the angle of incidence of radiation. This work measures how angular dependence of a nanoDot changes with the geometry of the phantom in which irradiation occurs and with the intrinsic structure of the nanoDot. Methods: The OSLDs used in this work were nanoDot dosimeters (Landauer, Inc., Glenwood, IL), which were read with a MicroStar reader (Landauer, Inc., Glenwood, IL). Dose to the OSLDs was delivered by 6 MV x-rays. NanoDots with various intrinsic sensitivities were irradiated in numerous phantoms thatmore » had geometric shapes of cylinders, rectangles, and a cube. Results: No angular dependence was seen in cylindrical phantoms, cubic phantoms, or rectangular phantoms with a thickness to width ratio of 0.3 or 1.5. An angular dependence of 1% was observed in rectangular phantoms with a thickness to width of 0.433–0.633. A group of nanoDots had sensitive layers with mass density of 2.42–2.58 g/cm{sup 3} and relative sensitivity of 0.92–1.09 and no difference in their angular dependence. Within experimental uncertainty, nanoDot measurements agree with a parallel-plate ion chamber at a depth of maximum dose. Conclusions: When irradiated in cylindrical, rectangular, and cubic phantoms, nanoDots show a maximum angular dependence of 1% or less at an incidence angle of 90°. For a sample of 78 new nanoDots, the range of their relative intrinsic sensitivity is 0.92–1.09. For a sample of ten nanoDots, on average, the mass in the sensitive layer is 73.1% Al{sub 2}O{sub 3}:C and 26.9% polyester. The mass density of the sensitive layer of a nanoDot disc is between 2.42 and 2.58 g/cm{sup 3}. The angular dependence is not related to Al{sub 2}O{sub 3}:C loading of the nanoDot disc. The nanoDot at the depth of maximum dose has no more angular dependence than a parallel-plate ion chamber.« less

3D positioning scheme exploiting nano-scale IR-UWB orthogonal pulses.

PubMed

Kim, Nammoon; Kim, Youngok

2011-10-04

In these days, the development of positioning technology for realizing ubiquitous environments has become one of the most important issues. The Global Positioning System (GPS) is a well-known positioning scheme, but it is not suitable for positioning in in-door/building environments because it is difficult to maintain line-of-sight condition between satellites and a GPS receiver. To such problem, various positioning methods such as RFID, WLAN, ZigBee, and Bluetooth have been developed for indoor positioning scheme. However, the majority of positioning schemes are focused on the two-dimension positioning even though three-dimension (3D) positioning information is more useful especially in indoor applications, such as smart space, U-health service, context aware service, etc. In this paper, a 3D positioning system based on mutually orthogonal nano-scale impulse radio ultra-wideband (IR-UWB) signals and cross array antenna is proposed. The proposed scheme uses nano-scale IR-UWB signals providing fine time resolution and high-resolution multiple signal specification algorithm for the time-of-arrival and the angle-of-arrival estimation. The performance is evaluated over various IEEE 802.15.4a channel models, and simulation results show the effectiveness of proposed scheme.

Fracture behavior of nano-scale rubber-modified epoxies

NASA Astrophysics Data System (ADS)

Bacigalupo, Lauren N.

The primary focus of the first portion of this study is to compare physical and mechanical properties of a model epoxy that has been toughened with one of three different types of rubber-based modifier: a traditional telechelic oligomer (phase separates into micro-size particles), a core-shell latex particle (preformed nano-scale particles) and a triblock copolymer (self-assembles into nano-scale particles). The effect of modifier content on the physical properties of the matrix was determined using several thermal analysis methods, which provided insight into any inherent alterations of the epoxy matrix. Although the primary objective is to study the role of particle size on the fracture toughness, stiffness and strength were also determined since these properties are often reduced in rubber-toughened epoxies. It was found that since the CSR- and SBM-modified epoxies are composed of less rubber, thermal and mechanical properties of the epoxy were better maintained. In order to better understand the fracture behavior and mechanisms of the three types of rubber particles utilized in this study, extensive microscopy analysis was conducted. Scanning transmission electron microscopy (STEM) was used to quantify the volume fraction of particles, transmission optical microscopy (TOM) was used to determine plastic damage zone size, and scanning electron microscopy (SEM) was used to assess void growth in the plastic zone after fracture. By quantifying these characteristics, it was then possible to model the plastic damage zone size as well as the fracture toughness to elucidate the behavior of the rubber-modified epoxies. It was found that localized shear yielding and matrix void growth are the active toughening mechanisms in all rubber-modified epoxies in this study, however, matrix void growth was more prevalent. The second portion of this study investigated the use of three acrylate-based triblocks and four acrylate-based diblocks to modify a model epoxy system. By

Modeling the Charge Transport in Graphene Nano Ribbon Interfaces for Nano Scale Electronic Devices

NASA Astrophysics Data System (ADS)

Kumar, Ravinder; Engles, Derick

2015-05-01

In this research work we have modeled, simulated and compared the electronic charge transport for Metal-Semiconductor-Metal interfaces of Graphene Nano Ribbons (GNR) with different geometries using First-Principle calculations and Non-Equilibrium Green's Function (NEGF) method. We modeled junctions of Armchair GNR strip sandwiched between two Zigzag strips with (Z-A-Z) and Zigzag GNR strip sandwiched between two Armchair strips with (A-Z-A) using semi-empirical Extended Huckle Theory (EHT) within the framework of Non-Equilibrium Green Function (NEGF). I-V characteristics of the interfaces were visualized for various transport parameters. The distinct changes in conductance and I-V curves reported as the Width across layers, Channel length (Central part) was varied at different bias voltages from -1V to 1 V with steps of 0.25 V. From the simulated results we observed that the conductance through A-Z-A graphene junction is in the range of 10-13 Siemens whereas the conductance through Z-A-Z graphene junction is in the range of 10-5 Siemens. These suggested conductance controlled mechanisms for the charge transport in the graphene interfaces with different geometries is important for the design of graphene based nano scale electronic devices like Graphene FETs, Sensors.

Studies of free-space optical links through simulated boundary layer and long-path turbulence

NASA Astrophysics Data System (ADS)

Wasiczko, Linda; Smolyaninov, Igor I.; Milner, Stuart D.; Davis, Christopher C.

2004-02-01

There is recent interest from the US Department of Defense in free space optical communication networks involving aircraft flying at various altitudes. The optical links between these aircraft may be as long as 100km, and involve communication between network nodes that are moving at sub-sonic speeds. An unresolved issue for links of this kind between pairs of aircraft is the effect of boundary layer turbulence near each aircraft, as well as along the atmospheric path between them. The deployment of optical wireless links in several different scenarios will be described. These include links near to the ground for which the turbulence parameter Cn2 varies along the path between transmitter (TX) and receiver (RX), high altitude links between aircraft, and ground to aircraft links. The last two of these may involve boundary layer turbulence near the aircraft node where the turbulence is localized either at the TX or at the RX. Some of the theoretical approaches to examining these situations will be described, as well as an ongoing program of research to examine these situations experimentally. Ways to mitigate the effects of node motion, and scintillation at the RX will be discussed, including the use of non-imaging concentrators at the RX.

Elastic transducers incorporating finite-length optical paths

NASA Astrophysics Data System (ADS)

Peters, Kara J.; Washabaugh, Peter D.

1995-08-01

Frequently, when designing a structure to incorporate integrated sensors, one sacrifices the stiffness of the system to improve sensitivity. However, the use of interferometric displacement sensors that tessellate throughout the volume of a structure has the potential to allow the precision and range of the component measurement to scale with the geometry of the device rather than the maximum strain in the structure. The design of stiff structures that measure all six resultant-load components is described. In addition, an advanced torsion sensor and a linear acceleration transducer are also discussed. Finally, invariant paths are presented that allow the in situ integrity of a structural volume to be monitored with a single pair of displacement sensors.

Chemical characterization of single micro- and nano-particles by optical catapulting-optical trapping-laser-induced breakdown spectroscopy

NASA Astrophysics Data System (ADS)

Fortes, Francisco J.; Fernández-Bravo, Angel; Javier Laserna, J.

2014-10-01

Spectral identification of individual micro- and nano-sized particles by the sequential intervention of optical catapulting, optical trapping and laser-induced breakdown spectroscopy is presented. The three techniques are used for different purposes. Optical catapulting (OC) serves to put the particulate material under inspection in aerosol form. Optical trapping (OT) permits the isolation and manipulation of individual particles from the aerosol, which are subsequently analyzed by laser-induced breakdown spectroscopy (LIBS). Once catapulted, the dynamics of particle trapping depends both on the laser beam characteristics (power and intensity gradient) and on the particle properties (size, mass and shape). Particles are stably trapped in air at atmospheric pressure and can be conveniently manipulated for a precise positioning for LIBS analysis. The spectra acquired from the individually trapped particles permit a straightforward identification of the material inspected. Variability of LIBS signal for the inspection of Ni microspheres was 30% relative standard deviation. OC-OT-LIBS permits the separation of particles in a heterogeneous mixture and the subsequent analysis of the isolated particle of interest. In order to evaluate the sensitivity of the approach, the number of absolute photons emitted by a single trapped particle was calculated. The limit of detection (LOD) for Al2O3 particles was calculated to be 200 attograms aluminium.

Single layer of MX3(M = Ti, Zr; X = S, Se, Te): a new platform for nano-electronics and optics

NASA Astrophysics Data System (ADS)

Jin, Yingdi; Li, Xingxing; Yang, Jinlong

A serial of two dimensional titanium and zirconium trichalcogenides nanosheets MX3 (M=Ti, Zr; X=S, Se, Te) are investigated based on first-principles calculations. The evaluated low cleavage energy indicates that stable two dimensional monolayers can be exfoliated from their bulk crystals in experiment. Electronic studies reveal very rich electronic properties in these monolayers, including metallic TiTe3 and ZrTe3, direct band gap semiconductor TiS3 and indirect band gap semiconductors TiSe3, ZrS3 and ZrSe3. The band gaps of all the semiconductors are between 0.57~1.90 eV, which implies their potential applications in nano-electronics. And the calculated effective masses demonstrate highly anisotropic conduction properties for all the semiconductors. Optically, TiS3 and TiSe3 monolayers exhibit good light absorption in the visible and near-infrared region respectively, indicating their potential applications in optical devices. In particular, the highly anisotropic optical absorption of TiS3 monolayer suggests it could be used in designing nano optical waveguide polarizers.

Slant-path coherent free space optical communications over the maritime and terrestrial atmospheres with the use of adaptive optics for beam wavefront correction.

PubMed

Li, Ming; Gao, Wenbo; Cvijetic, Milorad

2017-01-10

As a continuation of our previous work [Appl. Opt.54, 1453 (2015)APOPAI0003-693510.1364/AO.54.001453] in which we have studied the performance of coherent free space optical (FSO) communication systems operating over a horizontal path, in this paper we study the coherent FSO system operating over a general slant path. We evaluated system bit-error-rate (BER) in the case when the quadrature phase-shift keying (QPSK) modulation format is applied and when an adaptive optics (AO) system is employed to mitigate the air turbulence effects for both maritime and terrestrial air transmission scenarios. We adopted a multiple-layer scheme to efficiently model the FSO slant-path links. The atmospheric channel fading was characterized by the wavefront phase distortions and the log-amplitude fluctuations. We derived analytical expressions to characterize log-amplitude fluctuations of air turbulence by asserting the aperture averaging within the frame of the multiple-layer model. The obtained results showed that use of AO enabled improvement of system performance for both uplinks and downlinks, and also revealed that it is more beneficial for the FSO downlinks. Also, AO employment brought larger enhancements in BER performance for the maritime slant-path FSO links than for the terrestrial ones, with an additional striking increase in performance when the AO correction is combined with the aperture averaging.

Harnessing optical loss for unique microlaser functionality (Conference Presentation)

NASA Astrophysics Data System (ADS)

Feng, Liang

2017-05-01

Lasers, as the key driving force in the field of optics and photonics over other photonic components, are now being significantly benefited from the studies of nanophotonics and metamaterials, broadening laser physics and device applications. The properties of light are much more beyond its simple intensity and temporal characteristics. The fruitful nature of light provides a great variety of freedoms in manipulating light for modern photonic applications, including spin (polarization), chirality, angular momentum, and spin-orbit coupling. Unfortunately, all these fundamental properties and functionalities of light have not been fully exploited in micro/nano-laser systems because the conventional principles of laser design in bulk optics cannot be easily scaled down to the micro/nano scale. The capability of creating microlasers with controlled spin/orbital information and chirality in their radiations is expected to revolutionize next generation of photonic systems for computing and communication. In this talk, I will focus on our recent effort in harnessing optical losses for unique microlaser functionalities, in particular, an orbital angular momentum (OAM) microlaser that structure and twist the lasing radiation at the microscale. The effective generation of OAM lasing, especially at a micro/nano-scale, could address the growing demand for information capacity. By exploiting the emerging non-Hermitian photonics design at an exceptional point, we demonstrate a microring laser producing a single-mode OAM vortex lasing with the ability to precisely define the topological charge of the OAM mode and its polarization state. Our OAM microlaser could find applications in the next generation of integrated optoelectronic devices for optical communications.

Defect-free fabrication of nano-disk and nano-wire by fusion of bio-template and neutral beam etching

NASA Astrophysics Data System (ADS)

Samukawa, S.; Noda, Shuichi; Higo, Akio; Yasuda, Manabu; Wada, Kazumi

2016-11-01

We have developed an innovated fabrication technology of Si, GaAs, and Ge nano-structures, i.e., we called defect-free neutral beam etching. The technology has been successfully applied to prototype the quantum nano-disks and nano-wires with ferritin based bio-templates. SEM observation verifies that the designed structures are prototyped. Photoluminescence measurements demonstrates high optical quality of nano-structures based on the technology.

Demodulation algorithm for optical fiber F-P sensor.

PubMed

Yang, Huadong; Tong, Xinglin; Cui, Zhang; Deng, Chengwei; Guo, Qian; Hu, Pan

2017-09-10

The demodulation algorithm is very important to improving the measurement accuracy of a sensing system. In this paper, the variable step size hill climbing search method will be initially used for the optical fiber Fabry-Perot (F-P) sensing demodulation algorithm. Compared with the traditional discrete gap transformation demodulation algorithm, the computation is greatly reduced by changing step size of each climb, which could achieve nano-scale resolution, high measurement accuracy, high demodulation rates, and large dynamic demodulation range. An optical fiber F-P pressure sensor based on micro-electro-mechanical system (MEMS) has been fabricated to carry out the experiment, and the results show that the resolution of the algorithm can reach nano-scale level, the sensor's sensitivity is about 2.5  nm/KPa, which is similar to the theoretical value, and this sensor has great reproducibility.

Growth of periodic nano-layers of nano-crystals of Au, Ag, Cu by ion beam

NASA Technical Reports Server (NTRS)

Smith, Cydale C.; Zheng, B.; Muntele, C. I.; Muntele, I. C.; Ila, D.

2005-01-01

Multilayered thin films of SiO2/AU+ SiO2/, SiO2/Ag+ SiO2/, and SiO2/Cu+ SiO2/, were grown by deposition. We have previously shown that MeV ion Bombardment of multi-nano-layers of SiO2/AU+ SiO2/ produces Au nanocrystals in the AU+ SiO2 layers. An increased number of nano-layers followed by MeV ion bombardment produces a wide optical absorption band, of which its FWHM depends on the number of nano-layers of SiO2/AU+ SiO2/. We have successfully repeated this process for nano-layers of SiO2/Ag+ SiO2/, and SiO2/Cu+ SiO2/. In this work we used 5 MeV Si as the post deposition bombardment ion and monitored the location as well as the optical absorption's FWHM for each layered structure using Optical Absorption Photospectrometry. The concentration and location of the metal nano-crystals were measured by Rutherford Backscattering Spectrometry. We will report on the results obtained for nano-layered structures produced by post deposition bombardment of SiO2/AU+ SiO2/, SiO2/Ag+ SiO2/, and SiO2/Cu+ SiO2/ layered systems as well as the results obtained from a system containing a periodic combination of SiO2/AU+ SiO2/, SiO2/Ag+ SiO2/, and SiO2/Cu+ SiO2/.

Synthesis of Nano-Scale Fast Ion Conducting Cubic Li7La3Zr2O12

DTIC Science & Technology

2013-09-25

offer the flexibility to make nano-dimensional particles with high sinterability nor the ability to coat/protect electrode powders. By developing a...sintering temperature are needed. One possible approach is to use small particles , such as nano-scale particles , that can be sintered at lower temperatures...matrix to suppress Li dendrite penetration. By developing a sol–gel process, the LLZO particle size can be precisely tuned, from the nanometer to the

Chromium doped nano-phase separated yttria-alumina-silica glass based optical fiber preform: fabrication and characterization

NASA Astrophysics Data System (ADS)

Dutta, Debjit; Dhar, Anirban; Das, Shyamal; Bysakh, Sandip; Kir'yanov, Alexandar; Paul, Mukul Chandra

2015-06-01

Transition metal (TM) doping in silica core optical fiber is one of the research area which has been studied for long time and Chromium (Cr) doping specially attracts a lot of research interest due to their broad emission band covering U, C and L band with many potential application such as saturable absorber or broadband amplifier etc. This paper present fabrication of Cr doped nano-phase separated silica fiber within yttria-alumina-silica core glass through conventional Modified Chemical Vapor Deposition (MCVD) process coupled with solution doping technique along with different material and optical characterization. For the first time scanning electron microscope (SEM) / energy dispersive X-ray (EDX) analysis of porous soot sample and final preform has been utilized to investigate incorporation mechanism of Crions with special emphasis on Cr-species evaporation at different stages of fabrication. We also report that optimized annealing condition of our fabricated preform exhibited enhanced fluorescence emission and a broad band within 550- 800 nm wavelength region under pumping at 532 nm wavelength due to nano-phase restructuration.

Measurement of greenhouse gas emissions from agricultural sites using open-path optical remote sensing method.

PubMed

Ro, Kyoung S; Johnson, Melvin H; Varma, Ravi M; Hashmonay, Ram A; Hunt, Patrick

2009-08-01

Improved characterization of distributed emission sources of greenhouse gases such as methane from concentrated animal feeding operations require more accurate methods. One promising method is recently used by the USEPA. It employs a vertical radial plume mapping (VRPM) algorithm using optical remote sensing techniques. We evaluated this method to estimate emission rates from simulated distributed methane sources. A scanning open-path tunable diode laser was used to collect path-integrated concentrations (PICs) along different optical paths on a vertical plane downwind of controlled methane releases. Each cycle consists of 3 ground-level PICs and 2 above ground PICs. Three- to 10-cycle moving averages were used to reconstruct mass equivalent concentration plum maps on the vertical plane. The VRPM algorithm estimated emission rates of methane along with meteorological and PIC data collected concomitantly under different atmospheric stability conditions. The derived emission rates compared well with actual released rates irrespective of atmospheric stability conditions. The maximum error was 22 percent when 3-cycle moving average PICs were used; however, it decreased to 11% when 10-cycle moving average PICs were used. Our validation results suggest that this new VRPM method may be used for improved estimations of greenhouse gas emission from a variety of agricultural sources.

Laser Communications Relay Demonstration (LCRD) Update and the Path Towards Optical Relay Operations

NASA Technical Reports Server (NTRS)

Israel, David J.; Edwards, Bernard L.; Staren, John W.

2017-01-01

This paper provides a concept for an evolution of NASA's optical communications near Earth relay architecture. NASA's Laser Communications Relay Demonstration (LCRD), a joint project between NASA's Goddard Space Flight Center (GSFC), the Jet Propulsion Laboratory - California Institute of Technology (JPL), and the Massachusetts Institute of Technology Lincoln Laboratory (MIT LL). LCRD will provide a minimum of two years of high data rate optical communications service experiments in geosynchronous orbit (GEO), following launch in 2019. This paper will provide an update of the LCRD mission status and planned capabilities and experiments, followed by a discussion of the path from LCRD to operational network capabilities.

Laser Communications Relay Demonstration (LCRD) Update and the Path Towards Optical Relay Operations

NASA Technical Reports Server (NTRS)

Israel, David J.; Edwards, Bernard L.; Staren, John W.

2017-01-01

This Presentation provides a concept for an evolution of NASAs optical communications near Earth relay architecture. NASA's Laser Communications Relay Demonstration (LCRD), a joint project between NASAs Goddard Space Flight Center (GSFC), the Jet Propulsion Laboratory - California Institute of Technology (JPL), and the Massachusetts Institute of Technology Lincoln Laboratory (MIT LL). LCRD will provide a minimum of two years of high data rate optical communications service experiments in geosynchronous orbit (GEO), following launch in 2019. This paper will provide an update of the LCRD mission status and planned capabilities and experiments, followed by a discussion of the path from LCRD to operational network capabilities.

Cross-Polarization Optical Coherence Tomography with Active Maintenance of the Circular Polarization of a Sounding Wave in a Common Path System

NASA Astrophysics Data System (ADS)

Gelikonov, V. M.; Romashov, V. N.; Shabanov, D. V.; Ksenofontov, S. Yu.; Terpelov, D. A.; Shilyagin, P. A.; Gelikonov, G. V.; Vitkin, I. A.

2018-05-01

We consider a cross-polarization optical coherence tomography system with a common path for the sounding and reference waves and active maintenance of the circular polarization of a sounding wave. The system is based on the formation of birefringent characteristics of the total optical path, which are equivalent to a quarter-wave plate with a 45° orientation of its optical axes with respect to the linearly polarized reference wave. Conditions under which any light-polarization state can be obtained using a two-element phase controller are obtained. The dependence of the local cross-scattering coefficient of light in a model medium and biological tissue on the sounding-wave polarization state is demonstrated. The necessity of active maintenance of the circular polarization of a sounding wave in this common path system (including a flexible probe) is shown to realize uniform optimal conditions for cross-polarization studies of biological tissue.

Aligned Layers of Silver Nano-Fibers.

PubMed

Golovin, Andrii B; Stromer, Jeremy; Kreminska, Liubov

2012-02-01

We describe a new dichroic polarizers made by ordering silver nano-fibers to aligned layers. The aligned layers consist of nano-fibers and self-assembled molecular aggregates of lyotropic liquid crystals. Unidirectional alignment of the layers is achieved by means of mechanical shearing. Aligned layers of silver nano-fibers are partially transparent to a linearly polarized electromagnetic radiation. The unidirectional alignment and density of the silver nano-fibers determine degree of polarization of transmitted light. The aligned layers of silver nano-fibers might be used in optics, microwave applications, and organic electronics.

The viability and performance characterization of nano scale energetic materials on a semiconductor bridge (SCB)

NASA Astrophysics Data System (ADS)

Strohm, Gianna Sophia

The move from conventional energetic composites to nano scale energetic mixtures (nano energetics) has shown dramatic improvement in energy release rate and sensitivity to ignition. A possible application of nano energetics is on a semiconductor bridge (SCB). An SCB typically requires a tenth of the energy input as compared to a bridge wire design with the same no-fire and is capable of igniting in tens of microseconds. For very low energy applications, SCBs can be manufactured to extremely small sizes and it is necessary to find materials with particle sizes that are even smaller to function. Reactive particles of comparable size to the bridge can lead to problems with ignition reliability for small bridges. Nano-energetic composites and the use of SCBs have been significantly studied individually, however, the process of combining nano energetics with an SCB has not been investigated extensively and is the focus of this work. Goals of this study are to determine if nano energetics can be used with SCBs to further reduce the minimum energy required and improve reliability. The performance of nano-scale aluminum (nAl) and bismuth oxide (Bi2O3) with nitrocellulose (NC), Fluorel(TM) FC 2175 (chemically equivalent to VitonRTM) and Glycidyl Azide Polymer (GAP) as binders where quantified initially using the SenTest(TM) algorithm at three weight fractions (5, 7, and 9%) of binder. The threshold energy was calculated and compared to previous data using conventional materials such as zirconium potassium chlorate (ZPC), mercuric 5-Nitrotetrazol (DXN-1) and titanium sub-hydride potassium per-chlorate (TSPP). It was found that even though there where only slight differences in performance between the binders with nAl/Bi2O 3 at any of the three binder weight fractions, the results show that these nano energetic materials require about half of the threshold energy compared to conventional materials using an SCB with an 84x42 mum bridge. Binder limit testing was conducted to

Upconverting Nanoparticles as Optical Sensors of Nano- to Micro-Newton Forces.

PubMed

Lay, Alice; Wang, Derek S; Wisser, Michael D; Mehlenbacher, Randy D; Lin, Yu; Goodman, Miriam B; Mao, Wendy L; Dionne, Jennifer A

2017-07-12

Mechanical forces affect a myriad of processes, from bone growth to material fracture to touch-responsive robotics. While nano- to micro-Newton forces are prevalent at the microscopic scale, few methods have the nanoscopic size and signal stability to measure them in vivo or in situ. Here, we develop an optical force-sensing platform based on sub-25 nm NaYF 4 nanoparticles (NPs) doped with Yb 3+ , Er 3+ , and Mn 2+ . The lanthanides Yb 3+ and Er 3+ enable both photoluminescence and upconversion, while the energetically coupled d-metal Mn 2+ adds force tunability through its crystal field sensitivity. Using a diamond anvil cell to exert up to 3.5 GPa pressure or ∼10 μN force per particle, we track stress-induced spectral responses. The red (660 nm) to green (520, 540 nm) emission ratio varies linearly with pressure, yielding an observed color change from orange to red for α-NaYF 4 and from yellow-green to green for d-metal optimized β-NaYF 4 when illuminated in the near infrared. Consistent readouts are recorded over multiple pressure cycles and hours of illumination. With the nanoscopic size, a dynamic range of 100 nN to 10 μN, and photostability, these nanoparticles lay the foundation for visualizing dynamic mechanical processes, such as stress propagation in materials and force signaling in organisms.

Upconverting Nanoparticles as Optical Sensors of Nano- to Micro-Newton Forces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lay, Alice; Wang, Derek S.; Wisser, Michael D.

Mechanical forces affect a myriad of processes, from bone growth to material fracture to touch-responsive robotics. While nano- to micro-Newton forces are prevalent at the microscopic scale, few methods have the nanoscopic size and signal stability to measure them in vivo or in situ. Here, we develop an optical force-sensing platform based on sub-25 nm NaYF4 nanoparticles (NPs) doped with Yb3+, Er3+, and Mn2+. The lanthanides Yb3+ and Er3+ enable both photoluminescence and upconversion, while the energetically coupled d-metal Mn2+ adds force tunability through its crystal field sensitivity. Using a diamond anvil cell to exert up to 3.5 GPa pressuremore » or ~10 μN force per particle, we track stress-induced spectral responses. The red (660 nm) to green (520, 540 nm) emission ratio varies linearly with pressure, yielding an observed color change from orange to red for α-NaYF4 and from yellow–green to green for d-metal optimized β-NaYF4 when illuminated in the near infrared. Consistent readouts are recorded over multiple pressure cycles and hours of illumination. With the nanoscopic size, a dynamic range of 100 nN to 10 μN, and photostability, these nanoparticles lay the foundation for visualizing dynamic mechanical processes, such as stress propagation in materials and force signaling in organisms.« less

Campanile Near-Field Probes Fabricated by Nanoimprint Lithography on the Facet of an Optical Fiber

DOE PAGES

Calafiore, Giuseppe; Koshelev, Alexander; Darlington, Thomas P.; ...

2017-05-10

One of the major challenges to the widespread adoption of plasmonic and nano-optical devices in real-life applications is the difficulty to mass-fabricate nano-optical antennas in parallel and reproducible fashion, and the capability to precisely place nanoantennas into devices with nanometer-scale precision. In this study, we present a solution to this challenge using the state-of-the-art ultraviolet nanoimprint lithography (UV-NIL) to fabricate functional optical transformers onto the core of an optical fiber in a single step, mimicking the 'campanile' near-field probes. Imprinted probes were fabricated using a custom-built imprinter tool with co-axial alignment capability with sub < 100 nm position accuracy, followedmore » by a metallization step. Scanning electron micrographs confirm high imprint fidelity and precision with a thin residual layer to facilitate efficient optical coupling between the fiber and the imprinted optical transformer. The imprinted optical transformer probe was used in an actual NSOM measurement performing hyperspectral photoluminescence mapping of standard fluorescent beads. The calibration scans confirmed that imprinted probes enable sub-diffraction limited imaging with a spatial resolution consistent with the gap size. This novel nano-fabrication approach promises a low-cost, high-throughput, and reproducible manufacturing of advanced nano-optical devices.« less

Campanile Near-Field Probes Fabricated by Nanoimprint Lithography on the Facet of an Optical Fiber

DOE Office of Scientific and Technical Information (OSTI.GOV)

Calafiore, Giuseppe; Koshelev, Alexander; Darlington, Thomas P.

One of the major challenges to the widespread adoption of plasmonic and nano-optical devices in real-life applications is the difficulty to mass-fabricate nano-optical antennas in parallel and reproducible fashion, and the capability to precisely place nanoantennas into devices with nanometer-scale precision. In this study, we present a solution to this challenge using the state-of-the-art ultraviolet nanoimprint lithography (UV-NIL) to fabricate functional optical transformers onto the core of an optical fiber in a single step, mimicking the 'campanile' near-field probes. Imprinted probes were fabricated using a custom-built imprinter tool with co-axial alignment capability with sub < 100 nm position accuracy, followedmore » by a metallization step. Scanning electron micrographs confirm high imprint fidelity and precision with a thin residual layer to facilitate efficient optical coupling between the fiber and the imprinted optical transformer. The imprinted optical transformer probe was used in an actual NSOM measurement performing hyperspectral photoluminescence mapping of standard fluorescent beads. The calibration scans confirmed that imprinted probes enable sub-diffraction limited imaging with a spatial resolution consistent with the gap size. This novel nano-fabrication approach promises a low-cost, high-throughput, and reproducible manufacturing of advanced nano-optical devices.« less

Nano-Bio Quantum Technology for Device-Specific Materials

NASA Technical Reports Server (NTRS)

Choi, Sang H.

2009-01-01

The areas discussed are still under development: I. Nano structured materials for TE applications a) SiGe and Be.Te; b) Nano particles and nanoshells. II. Quantum technology for optical devices: a) Quantum apertures; b) Smart optical materials; c) Micro spectrometer. III. Bio-template oriented materials: a) Bionanobattery; b) Bio-fuel cells; c) Energetic materials.

Remote artificial eyes using micro-optical circuit for long-distance 3D imaging perception.

PubMed

Thammawongsa, Nopparat; Yupapin, Preecha P

2016-01-01

A small-scale optical device incorporated with an optical nano-antenna is designed to operate as the remote artificial eye using a tiny conjugate mirror. A basic device known as a conjugate mirror can be formed using the artificial eye device, the partially reflected light intensities from input source are interfered and the 3D whispering gallery modes formed within the ring centers, which can be modulated and propagated to the object. The image pixel is obtained at the center ring and linked with the optic nerve in the remote area via the nano-antenna, which is useful for blind people.

Changes in diffusion path length with old age in diffuse optical tomography

NASA Astrophysics Data System (ADS)

Bonnéry, Clément; Leclerc, Paul-Olivier; Desjardins, Michèle; Hoge, Rick; Bherer, Louis; Pouliot, Philippe; Lesage, Frédéric

2012-05-01

Diffuse, optical near infrared imaging is increasingly being used in various neurocognitive contexts where changes in optical signals are interpreted through activation maps. Statistical population comparison of different age or clinical groups rely on the relative homogeneous distribution of measurements across subjects in order to infer changes in brain function. In the context of an increasing use of diffuse optical imaging with older adult populations, changes in tissue properties and anatomy with age adds additional confounds. Few studies investigated these changes with age. Duncan et al. measured the so-called diffusion path length factor (DPF) in a large population but did not explore beyond the age of 51 after which physiological and anatomical changes are expected to occur [Pediatr. Res. 39(5), 889-894 (1996)]. With increasing interest in studying the geriatric population with optical imaging, we studied changes in tissue properties in young and old subjects using both magnetic resonance imaging (MRI)-guided Monte-Carlo simulations and time-domain diffuse optical imaging. Our results, measured in the frontal cortex, show changes in DPF that are smaller than previously measured by Duncan et al. in a younger population. The origin of these changes are studied using simulations and experimental measures.

Selective laser processing of ink-jet printed nano-scaled tin-clad copper particles

NASA Astrophysics Data System (ADS)

Yung, K. C.; Plura, T. S.

2010-11-01

The deposition of tin-clad nano-size copper particles was carried out by means of ink-jet printing. Curing the particles on Polyimide (PI) turned them into soldered structures using an Nd-YAG laser. Area coverage of 55% was achieved for a single-layer print. Subsequent laser sintering increased this value to 95%. A Butanol-based copper ink and an aqueous tin (Sn)-clad Copper (Cu) ink were produced and were ink-jetted in this work. These nano-metallic inks showed excellent suspension stability with particle weight concentrations as high as 5%. The ink components were examined by measuring the particle size distribution in a dispersed condition, and the melting temperature. A piezo ink-jet print head was used to deposit the inks onto a moveable substrate. The thermal effect of the laser irradiation allowed approaching and connecting adjacent particles by melting the particle’s tin coating. The results were examined with regard to structure and soldering properties using EDX, SEM and optical microscopy.

CPP-GMR films with a current-confined-path nano-oxide layer (CCP-NOL)

NASA Astrophysics Data System (ADS)

Fukuzawa, Hideaki; Yuasa, Hiromi; Iwasaki, Hitoshi

2007-03-01

We investigated the film performance and nanostructure of current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) spin-valve film with a current-confined-path nano-oxide layer (CCP-NOL). By applying ion-assisted oxidation (IAO) for the CCP-NOL formation, we enhanced the MR ratio to 5.4% at a small RA value of 500 mΩ µm2 for conventional Co90Fe10 layers. Furthermore, the use of bcc-Fe50Co50 also increased the MR ratio to 8.2% at a small RA value of 580 mΩ µm2. A modified Valet-Fert model for the CCP-NOL showed that the MR enhancement by the IAO is due to the improvement in resistivity of the CCP, and that by Fe50Co50 is due to a larger spin-dependent interface scattering effect. Analysis by cross-sectional TEM and three-dimensional atom probe confirmed the formation of the CCP-NOL structure. A reliability test for test element devices showed almost no change even under acceleration stress. The CPP-GMR spin-valve film with the CCP-NOL is extendable to future high-density recording heads due to its potential for a higher MR ratio at a small value of RA.

Arbitrary unitary transformations on optical states using a quantum memory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Campbell, Geoff T.; Pinel, Olivier; Hosseini, Mahdi

2014-12-04

We show that optical memories arranged along an optical path can perform arbitrary unitary transformations on frequency domain optical states. The protocol offers favourable scaling and can be used with any quantum memory that uses an off-resonant Raman transition to reversibly transfer optical information to an atomic spin coherence.

Ignition dynamics and activation energies of metallic thermites: From nano- to micron-scale particulate composites

NASA Astrophysics Data System (ADS)

Hunt, Emily M.; Pantoya, Michelle L.

2005-08-01

Ignition behaviors associated with nano- and micron-scale particulate composite thermites were studied experimentally and modeled theoretically. The experimental analysis utilized a CO2 laser ignition apparatus to ignite the front surface of compacted nickel (Ni) and aluminum (Al) pellets at varying heating rates. Ignition delay time and ignition temperature as a function of both Ni and Al particle size were measured using high-speed imaging and microthermocouples. The apparent activation energy was determined from this data using a Kissinger isoconversion method. This study shows that the activation energy is significantly lower for nano- compared with micron-scale particulate media (i.e., as low as 17.4 compared with 162.5kJ /mol, respectively). Two separate Arrhenius-type mathematical models were developed that describe ignition in the nano- and the micron-composite thermites. The micron-composite model is based on a heat balance while the nanocomposite model incorporates the energy of phase transformation in the alumina shell theorized to be an initiating step in the solid-solid diffusion reaction and uniquely appreciable in nanoparticle media. These models were found to describe the ignition of the Ni /Al alloy for a wide range of heating rates.

Feasibility of Pb phytoextraction using nano-materials assisted ryegrass: Results of a one-year field-scale experiment.

PubMed

Liang, Shu-Xuan; Jin, Yu; Liu, Wei; Li, Xiliang; Shen, Shi-Gang; Ding, Ling

2017-04-01

The effect of the combined application of nano-hydroxyapatite (NHAP) or nano-carbon black (NCB) on the phytoextraction of Pb by ryegrass was investigated as an enhanced remediation technique for soils by field-scale experiment. After the addition of 0.2% NHAP or NCB to the soil, temporal variation of the uptake of Pb in aboveground parts and roots were observed. Ryegrass shoot concentrations of Pb were lower with nano-materials application than without nano-materials for the first month. However, the shoot concentrations of Pb were significantly increased with nano-materials application, in particular NHAP groups. The ryegrass root concentrations of Pb were lower with nano-materials application for the first month. These results indicated that nano-materials had significant effects on stabilization of lead, especially at the beginning of the experiment. Along with the experimental proceeding, phytotoxicity was alleviated after the incorporation of nano-materials. The ryegrass biomass was significantly higher with nano-materials application. Consequently, the Pb phytoextraction potential of ryegrass significantly increased with nano-materials application compared to the gounps without nano-materials application. The total removal rates of soil Pb were higher after combined application of NHAP than NCB. NHAP is more suitable than NCB for in-situ remediation of Pb-contaminated soils. The ryegrass translocation factor exhibited a marked increase with time. It was thought that the major role of NHP and NBA might be to alleviate the Pb phytotoxicity and increase biomass of plants. Copyright © 2016 Elsevier Ltd. All rights reserved.

Going the distance: spatial scale of athletic experience affects the accuracy of path integration.

PubMed

Smith, Alastair D; Howard, Christina J; Alcock, Niall; Cater, Kirsten

2010-09-01

Evidence suggests that athletically trained individuals are more accurate than untrained individuals in updating their spatial position through idiothetic cues. We assessed whether training at different spatial scales affects the accuracy of path integration. Groups of rugby players (large-scale training) and martial artists (small-scale training) participated in a triangle-completion task: they were led (blindfolded) along two sides of a right-angled triangle and were required to complete the hypotenuse by returning to the origin. The groups did not differ in their assessment of the distance to the origin, but rugby players were more accurate than martial artists in assessing the correct angle to turn (heading), and landed significantly closer to the origin. These data support evidence that distance and heading components can be dissociated. Furthermore, they suggest that the spatial scale at which an individual is trained may affect the accuracy of one component of path integration but not the other.

Turbulent Channel Flow Measurements with a Nano-scale Thermal Anemometry Probe

NASA Astrophysics Data System (ADS)

Bailey, Sean; Witte, Brandon

2014-11-01

Using a Nano-scale Thermal Anemometry Probe (NSTAP), streamwise velocity was measured in a turbulent channel flow wind tunnel at Reynolds numbers ranging from Reτ = 500 to Reτ = 4000 . Use of these probes results in the a sensing-length-to-viscous-length-scale ratio of just 5 at the highest Reynolds number measured. Thus measured results can be considered free of spatial filtering effects. Point statistics are compared to recently published DNS and LDV data at similar Reynolds numbers and the results are found to be in good agreement. However, comparison of the measured spectra provide further evidence of aliasing at long wavelengths due to application of Taylor's frozen flow hypothesis, with increased aliasing evident with increasing Reynolds numbers. In addition to conventional point statistics, the dissipative scales of turbulence are investigated with focus on the wall-dependent scaling. Results support the existence of a universal pdf distribution of these scales once scaled to account for large-scale anisotropy. This research is supported by KSEF Award KSEF-2685-RDE-015.

OVMS: the optical path difference and vibration monitoring system for the LBT and its interferometers

NASA Astrophysics Data System (ADS)

Kürster, M.; Bertram, T.; Borelli, J. L.; Brix, M.; Gässler, W.; Herbst, T. M.; Naranjo, V.; Pott, J.-U.; Trowitzsch, J.; Connors, T. E.; Hinz, P. M.; McMahon, T. J.; Ashby, D. S.; Brynnel, J. G.; Cushing, N. J.; Edgin, T.; Esguerra, J. D.; Green, R. F.; Kraus, J.; Little, J.; Beckmann, U.; Weigelt, G. P.

2010-07-01

Characterisation, mitigation and correction of telescope vibrations have proven to be crucial for the performance of astronomical infrared interferometers. The project teams of the interferometers for the LBT, LINC-NIRVANA and LBTI, and LBT Observatory (LBTO) have embarked on a joint effort to implement an accelerometer-based vibration measurement system distributed over the optical elements of the LBT. OVMS, the Optical Path Difference and Vibration Monitoring System will serve to (i) ensure conditions suitable for adaptive optics (AO) and interferometric (IF) observations and (ii) utilize vibration information, converted into tip-tilt and optical path difference data, in the control strategies of the LBT adaptive secondary mirrors and the beam combining interferometers. The system hardware is mainly developed by Steward Observatory's LBTI team and its installation at the LBT is underway. The OVMS software development and associated computer infrastructure is the responsibility of the LINC-NIRVANA team at MPIA Heidelberg. Initially, the OVMS will fill a data archive provided by LBTO that will be used to study vibration data and correlate them with telescope movements and environmental parameters thereby identifiying sources of vibrations and to eliminate or mitigate them. Data display tools will help LBTO staff to keep vibrations within predefined thresholds for quiet conditions for AO and IF observations. Later-on real-time data from the OVMS will be fed into the control loops of the AO systems and IF instruments in order to permit the correction of vibration signals with frequencies up to 450 Hz.

Hard paths, soft paths or no paths? Cross-cultural perceptions of water solutions

NASA Astrophysics Data System (ADS)

Wutich, A.; White, A. C.; White, D. D.; Larson, K. L.; Brewis, A.; Roberts, C.

2014-01-01

In this study, we examine how development status and water scarcity shape people's perceptions of "hard path" and "soft path" water solutions. Based on ethnographic research conducted in four semi-rural/peri-urban sites (in Bolivia, Fiji, New Zealand, and the US), we use content analysis to conduct statistical and thematic comparisons of interview data. Our results indicate clear differences associated with development status and, to a lesser extent, water scarcity. People in the two less developed sites were more likely to suggest hard path solutions, less likely to suggest soft path solutions, and more likely to see no path to solutions than people in the more developed sites. Thematically, people in the two less developed sites envisioned solutions that involve small-scale water infrastructure and decentralized, community-based solutions, while people in the more developed sites envisioned solutions that involve large-scale infrastructure and centralized, regulatory water solutions. People in the two water-scarce sites were less likely to suggest soft path solutions and more likely to see no path to solutions (but no more likely to suggest hard path solutions) than people in the water-rich sites. Thematically, people in the two water-rich sites seemed to perceive a wider array of unrealized potential soft path solutions than those in the water-scarce sites. On balance, our findings are encouraging in that they indicate that people are receptive to soft path solutions in a range of sites, even those with limited financial or water resources. Our research points to the need for more studies that investigate the social feasibility of soft path water solutions, particularly in sites with significant financial and natural resource constraints.

Hard paths, soft paths or no paths? Cross-cultural perceptions of water solutions

NASA Astrophysics Data System (ADS)

Wutich, A.; White, A. C.; Roberts, C. M.; White, D. D.; Larson, K. L.; Brewis, A.

2013-06-01

In this study, we examine how development status and water scarcity shape people's perceptions of "hard path" and "soft path" water solutions. Based on ethnographic research conducted in four semi-rural/peri-urban sites (in Bolivia, Fiji, New Zealand, and the US), we use content analysis to conduct statistical and thematic comparisons of interview data. Our results indicate clear differences based on development status and, to a lesser extent, water scarcity. People in less developed sites were more likely to suggest hard path solutions, less likely to suggest soft path solutions, and more likely to see no path to solutions than people in more developed sites. Thematically, people in less developed sites envisioned solutions that involve small-scale water infrastructure and decentralized, community based solutions, while people in more developed sites envisioned solutions that involve large-scale infrastructure and centralized, regulatory water solutions. People in water-scarce sites were less likely to suggest soft path solutions and more likely to see no path to solutions (but no more likely to suggest hard path solutions) than people in water-rich sites. Thematically, people in water-rich sites seemed to perceive a wider array of unrealized potential soft path solutions than those in water-scarce sites. On balance, our findings are encouraging in that they indicate that people are receptive to soft path solutions in a range of sites, even those with limited financial or water resources. Our research points to the need for more studies that investigate the social feasibility of soft path water solutions, particularly in sites with significant financial and natural resource constraints.

Nonadiabatic quantum path analysis of high-order harmonic generation: Role of the carrier-envelope phase on short and long paths

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sansone, G.; Stagira, S.; Nisoli, M.

2004-07-01

High-order harmonic generation process in the few- and multiple-optical-cycle regime is theoretically investigated, using the saddle-point method generalized to account for nonadiabatic effects. The influence of the carrier-envelope phase of the driving pulses on the various electron quantum paths is analyzed. We demonstrate that the short and long quantum paths are influenced in different ways by the carrier-envelope phase. In particular, we show that clear phase effects are visible on the long quantum paths even in the multiple-optical-cycle regime, while the short quantum paths are significantly influenced by the carrier-envelope phase only in the few-optical-cycle regime.

Development of a Cryostat to Characterize Nano-scale Superconducting Quantum Interference Devices

NASA Astrophysics Data System (ADS)

Longo, Mathew; Matheny, Matthew; Knudsen, Jasmine

2016-03-01

We have designed and constructed a low-noise vacuum cryostat to be used for the characterization of nano-scale superconducting quantum interference devices (SQUIDs). Such devices are very sensitive to magnetic fields and can measure changes in flux on the order of a single electron magnetic moment. As a part of the design process, we calculated the separation required between the cryogenic preamplifier and superconducting magnet, including a high-permeability magnetic shield, using a finite-element model of the apparatus. The cryostat comprises a vacuum cross at room temperature for filtered DC and shielded RF electrical connections, a thin-wall stainless steel support tube, a taper-sealed cryogenic vacuum can, and internal mechanical support and wiring for the nanoSQUID. The Dewar is modified with a room-temperature flange with a sliding seal for the cryostat. The flange supports the superconducting 3 Tesla magnet and thermometry wiring. Upon completion of the cryostat fabrication and Dewar modifications, operation of the nanoSQUIDs as transported from our collaborator's laboratory in Israel will be confirmed, as the lead forming the SQUID is sensitive to oxidation and the SQUIDs must be shipped in a vacuum container. After operation of the nanoSQUIDs is confirmed, the primary work of characterizing their high-speed properties will begin. This will include looking at the measurement of relaxation oscillations at high bandwidth in comparison to the theoretical predictions of the current model.

Optical Sensing And Imaging Opportunities

DTIC Science & Technology

2016-02-12

Functional Materials Workshops, supported by AFOSR.Potentially Useful New Research Areas.- Plasmonics - Infrared antennae- IV-VI (lead salt) Infrared Photo...Potentially Useful New Research Areas. - Plasmonics - Infrared antennae - IV-VI (lead salt) Infrared Photo Detectors and Focal Plane Arrays...Hexagonal Ferrite Thin Films for Q-Band Signal Processing Devices Plasmonics New techniques for transmitting optical signals through nano-scale

Low efficiency upconversion nanoparticles for high-resolution coalignment of near-infrared and visible light paths on a light microscope

PubMed Central

Sundaramoorthy, Sriramkumar; Badaracco, Adrian Garcia; Hirsch, Sophia M.; Park, Jun Hong; Davies, Tim; Dumont, Julien; Shirasu-Hiza, Mimi; Kummel, Andrew C.; Canman, Julie C.

2017-01-01

The combination of near infrared (NIR) and visible wavelengths in light microscopy for biological studies is increasingly common. For example, many fields of biology are developing the use of NIR for optogenetics, in which an NIR laser induces a change in gene expression and/or protein function. One major technical barrier in working with both NIR and visible light on an optical microscope is obtaining their precise coalignment at the imaging plane position. Photon upconverting particles (UCPs) can bridge this gap as they are excited by NIR light but emit in the visible range via an anti-Stokes luminescence mechanism. Here, two different UCPs have been identified, high-efficiency micro540-UCPs and lower efficiency nano545-UCPs, that respond to NIR light and emit visible light with high photostability even at very high NIR power densities (>25,000 Suns). Both of these UCPs can be rapidly and reversibly excited by visible and NIR light and emit light at visible wavelengths detectable with standard emission settings used for Green Fluorescent Protein (GFP), a commonly used genetically-encoded fluorophore. However, the high efficiency micro540-UCPs were suboptimal for NIR and visible light coalignment, due to their larger size and spatial broadening from particle-to-particle energy transfer consistent with a long lived excited state and saturated power dependence. In contrast, the lower efficiency nano-UCPs were superior for precise coalignment of the NIR beam with the visible light path (~2 µm versus ~8 µm beam broadening respectively) consistent with limited particle-to-particle energy transfer, superlinear power dependence for emission, and much smaller particle size. Furthermore, the nano-UCPs were superior to a traditional two-camera method for NIR and visible light path alignment in an in vivo Infrared-Laser-Evoked Gene Operator (IR-LEGO) optogenetics assay in the budding yeast S. cerevisiae. In summary, nano-UCPs are powerful new tools for coaligning NIR and

The element level time domain (ELTD) method for the analysis of nano-optical systems: I. Nondispersive media

NASA Astrophysics Data System (ADS)

Fallahi, Arya; Oswald, Benedikt; Leidenberger, Patrick

2012-04-01

We study a 3-dimensional, dual-field, fully explicit method for the solution of Maxwell's equations in the time domain on unstructured, tetrahedral grids. The algorithm uses the element level time domain (ELTD) discretization of the electric and magnetic vector wave equations. In particular, the suitability of the method for the numerical analysis of nanometer structured systems in the optical region of the electromagnetic spectrum is investigated. The details of the theory and its implementation as a computer code are introduced and its convergence behavior as well as conditions for stable time domain integration is examined. Here, we restrict ourselves to non-dispersive dielectric material properties since dielectric dispersion will be treated in a subsequent paper. Analytically solvable problems are analyzed in order to benchmark the method. Eventually, a dielectric microlens is considered to demonstrate the potential of the method. A flexible method of 2nd order accuracy is obtained that is applicable to a wide range of nano-optical configurations and can be a serious competitor to more conventional finite difference time domain schemes which operate only on hexahedral grids. The ELTD scheme can resolve geometries with a wide span of characteristic length scales and with the appropriate level of detail, using small tetrahedra where delicate, physically relevant details must be modeled.

Modelling rapid subsurface flow at the hillslope scale with explicit representation of preferential flow paths

NASA Astrophysics Data System (ADS)

Wienhöfer, J.; Zehe, E.

2012-04-01

Rapid lateral flow processes via preferential flow paths are widely accepted to play a key role for rainfall-runoff response in temperate humid headwater catchments. A quantitative description of these processes, however, is still a major challenge in hydrological research, not least because detailed information about the architecture of subsurface flow paths are often impossible to obtain at a natural site without disturbing the system. Our study combines physically based modelling and field observations with the objective to better understand how flow network configurations influence the hydrological response of hillslopes. The system under investigation is a forested hillslope with a small perennial spring at the study area Heumöser, a headwater catchment of the Dornbirnerach in Vorarlberg, Austria. In-situ points measurements of field-saturated hydraulic conductivity and dye staining experiments at the plot scale revealed that shrinkage cracks and biogenic macropores function as preferential flow paths in the fine-textured soils of the study area, and these preferential flow structures were active in fast subsurface transport of artificial tracers at the hillslope scale. For modelling of water and solute transport, we followed the approach of implementing preferential flow paths as spatially explicit structures of high hydraulic conductivity and low retention within the 2D process-based model CATFLOW. Many potential configurations of the flow path network were generated as realisations of a stochastic process informed by macropore characteristics derived from the plot scale observations. Together with different realisations of soil hydraulic parameters, this approach results in a Monte Carlo study. The model setups were used for short-term simulation of a sprinkling and tracer experiment, and the results were evaluated against measured discharges and tracer breakthrough curves. Although both criteria were taken for model evaluation, still several model setups

Challenges for the Modern Science in its Descend Towards Nano Scale

PubMed Central

Uskoković, Vuk

2013-01-01

The current rise in the interest in physical phenomena at nano spatial scale is described hereby as a natural consequence of the scientific progress in manipulation with matter with an ever higher sensitivity. The reason behind arising of the entirely new field of nanoscience is that the properties of nanostructured materials may significantly differ from their bulk counterparts and cannot be predicted by extrapolations of the size-dependent properties displayed by materials composed of microsized particles. It is also argued that although a material can comprise critical boundaries at the nano scale, this does not mean that it will inevitably exhibit properties that endow a nanomaterial. This implies that the attribute of “nanomaterial” can be used only in relation with a given property of interest. The major challenges faced with the expansion of resolution of the materials design, in terms of hardly reproducible experiments, are further discussed. It is claimed that owing to an unavoidable interference between the experimental system and its environment to which the controlling system belongs, an increased fineness of the experimental settings will lead to ever more difficulties in rendering them reproducible and controllable. Self-assembly methods in which a part of the preprogrammed scientific design is substituted with letting physical systems spontaneously evolve into attractive and functional structures is mentioned as one of the ways to overcome the problems inherent in synthetic approaches at the ultrafine scale. The fact that physical systems partly owe their properties to the interaction with their environment implies that each self-assembly process can be considered a co-assembly event. PMID:26491428

Evaporation of Liquid Droplet in Nano and Micro Scales from Statistical Rate Theory.

PubMed

Duan, Fei; He, Bin; Wei, Tao

2015-04-01

The statistical rate theory (SRT) is applied to predict the average evaporation flux of liquid droplet after the approach is validated in the sessile droplet experiments of the water and heavy water. The steady-state experiments show a temperature discontinuity at the evaporating interface. The average evaporation flux is evaluated by individually changing the measurement at a liquid-vapor interface, including the interfacial liquid temperature, the interfacial vapor temperature, the vapor-phase pressure, and the droplet size. The parameter study shows that a higher temperature jump would reduce the average evaporation flux. The average evaporation flux can significantly be influenced by the interfacial liquid temperature and the vapor-phase pressure. The variation can switch the evaporation into condensation. The evaporation flux is found to remain relative constant if the droplet is larger than a micro scale, while the smaller diameters in nano scale can produce a much higher evaporation flux. In addition, a smaller diameter of droplets with the same liquid volume has a larger surface area. It is suggested that the evaporation rate increases dramatically as the droplet shrinks into nano size.

Nano-optical imaging of WS e 2 waveguide modes revealing light-exciton interactions

DOE PAGES

Fei, Z.; Scott, M. E.; Gosztola, D. J.; ...

2016-08-01

We report on a nano-optical imaging study of WSe 2 thin flakes with scanning near-field optical microscopy (NSOM). The NSOM technique allows us to visualize in real space various waveguide photon modes inside WSe 2. By tuning the excitation laser energy, we are able to map the entire dispersion of these waveguide modes both above and below the A exciton energy of WSe 2. We found that all the modes interact strongly with WSe 2 excitons. The outcome of the interaction is that the observed waveguide modes shift to higher momenta right below the A exciton energy. At higher energies,more » on the other hand, these modes are strongly damped due to adjacent B excitons or band-edge absorptions. Lastly, the mode-shifting phenomena are consistent with polariton formation in WSe 2.« less

Analytical study of nano-scale logical operations

NASA Astrophysics Data System (ADS)

Patra, Moumita; Maiti, Santanu K.

2018-07-01

A complete analytical prescription is given to perform three basic (OR, AND, NOT) and two universal (NAND, NOR) logic gates at nano-scale level using simple tailor made geometries. Two different geometries, ring-like and chain-like, are taken into account where in each case the bridging conductor is coupled to a local atomic site through a dangling bond whose site energy can be controlled by means of external gate electrode. The main idea is that when injecting electron energy matches with site energy of local atomic site transmission probability drops exactly to zero, whereas the junction exhibits finite transmission for other energies. Utilizing this prescription we perform logical operations, and, we strongly believe that the proposed results can be verified in laboratory. Finally, we numerically compute two-terminal transmission probability considering general models and the numerical results match exactly well with our analytical findings.

Nano-scale Characterization of Basalt - Quenched Lava and Reheated Products

NASA Astrophysics Data System (ADS)

Burkhard, D. J.; Wirth, R.

2001-12-01

In order to trace the mechanism of crystallization in basalt we investigated basalt lava from active Pu'u O'o, Kilauea, Hawaii with TEM. We considered (1) quenched melt (glass, obtained by dipping a hammer into the lava (April 1996) and subsequent quenching in air), and (2) that glass after reheating for 48 hr at 850° C, and (3) after reheating for 48 hr at 930° C. Previous investigations had illustrated interface-controlled growth of pyroxene and Fe-Ti oxides at 850° C and volumetric growth of these phases in addition to plagioclase above 920° C [1]. In general, (1) is a perfect glass to the nano-scale. Occasional inhomogeneities are identified as plagioclase. With a size of no more than approximately 100 unit cells, these "crystals" might be considered as nuclei. Dendrites of pyroxene, identified on the micron scale with back scattered electrons [1], occur as a sequence of slightly displaced plates with equal orientation on the nano-scale. HREM, diffraction pattern and EDS confirm that this is augite, in agreement with investigations on the micron-scale [1]. Fe-Ti oxides occur isolated in the matrix with a diameter less than 100 nm, in contrast to the micron-scale, where Fe-Ti oxides appear at the apices of augite. In (3) we find in addition plagioclase with thin lamellae, indicating twinning. In (3),augite contains lamellae parallel to (001), and they are identified as pigeonite by HREM and electron diffraction. Pigeonite lamellae occur also in (2), however, less developed. Electron diffraction suggests that reflections of augite correspond to the space group C 2/c, and of exsolved pigeonite to P 21/c, which is a low pigeonite. These exsolution phenomena are undistiguishable from what is usually observed in relation to high cooling rates [e.g. 2]. The stability of pigeonite at these temperatures suggests a Fe/Fe+Mg ratio above 0.6 for pyroxene in the quadilateral [3]. Microprobe analyses [1] suggest ratios of 0.4 to 0.5. [1] Burkhard D.J.M. (2001) J. Petrol

On-chip optical transduction scheme for graphene nano-electro-mechanical systems in silicon-photonic platform

NASA Astrophysics Data System (ADS)

Dash, Aneesh; Selvaraja, S. K.; Naik, A. K.

2018-02-01

We present a scheme for on-chip optical transduction of strain and displacement of Graphene-based Nano-Electro-Mechanical Systems (NEMS). A detailed numerical study on the feasibility of three silicon-photonic integrated circuit configurations is presented: Mach-Zehnder Interferometer(MZI), micro-ring resonator and ring-loaded MZI. An index-sensing based technique using a Mach-Zehnder Interferometer loaded with a ring resonator with a moderate Q-factor of 2400 can yield a sensitivity of 28 fm/sqrt(Hz), and 6.5E-6 %/sqrt(Hz) for displacement and strain respectively. Though any phase sensitive integrated photonic device could be used for optical transduction, here we show that optimal sensitivity is achievable by combining resonance with phase sensitivity.

Upconverting Nanoparticles as Optical Sensors of Nano- to Micro-Newton Forces

DOE PAGES

Lay, Alice; Wang, Derek S.; Wisser, Michael D.; ...

2017-06-13

Mechanical forces affect a myriad of processes, from bone growth to material fracture to touch-responsive robotics. While nano- to micro-Newton forces are prevalent at the microscopic scale, few methods have the nanoscopic size and signal stability to measure them in vivo or in situ. Here, we develop an optical force-sensing platform based on sub-25 nm NaYF 4 nanoparticles (NPs) doped with Yb 3+, Er 3+, and Mn 2+. The lanthanides Yb 3+ and Er 3+ enable both photoluminescence and upconversion, while the energetically coupled d-metal Mn 2+ adds force tunability through its crystal field sensitivity. IN using a diamond anvilmore » cell to exert up to 3.5 GPa pressure or ~10 μN force per particle, we track stress-induced spectral responses. The red (660 nm) to green (520, 540 nm) emission ratio varies linearly with pressure, yielding an observed color change from orange to red for α-NaYF 4 and from yellow–green to green for d-metal optimized β-NaYF 4 when illuminated in the near infrared. We record consistent readouts over multiple pressure cycles and hours of illumination. With the nanoscopic size, a dynamic range of 100 nN to 10 μN, and photostability, these nanoparticles lay the foundation for visualizing dynamic mechanical processes, such as stress propagation in materials and force signaling in organisms.« less

Upconverting Nanoparticles as Optical Sensors of Nano- to Micro-Newton Forces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lay, Alice; Wang, Derek S.; Wisser, Michael D.

Mechanical forces affect a myriad of processes, from bone growth to material fracture to touch-responsive robotics. While nano- to micro-Newton forces are prevalent at the microscopic scale, few methods have the nanoscopic size and signal stability to measure them in vivo or in situ. Here, we develop an optical force-sensing platform based on sub-25 nm NaYF 4 nanoparticles (NPs) doped with Yb 3+, Er 3+, and Mn 2+. The lanthanides Yb 3+ and Er 3+ enable both photoluminescence and upconversion, while the energetically coupled d-metal Mn 2+ adds force tunability through its crystal field sensitivity. IN using a diamond anvilmore » cell to exert up to 3.5 GPa pressure or ~10 μN force per particle, we track stress-induced spectral responses. The red (660 nm) to green (520, 540 nm) emission ratio varies linearly with pressure, yielding an observed color change from orange to red for α-NaYF 4 and from yellow–green to green for d-metal optimized β-NaYF 4 when illuminated in the near infrared. We record consistent readouts over multiple pressure cycles and hours of illumination. With the nanoscopic size, a dynamic range of 100 nN to 10 μN, and photostability, these nanoparticles lay the foundation for visualizing dynamic mechanical processes, such as stress propagation in materials and force signaling in organisms.« less

Vehicle path-planning in three dimensions using optics analogs for optimizing visibility and energy cost

NASA Technical Reports Server (NTRS)

Rowe, Neil C.; Lewis, David H.

1989-01-01

Path planning is an important issue for space robotics. Finding safe and energy-efficient paths in the presence of obstacles and other constraints can be complex although important. High-level (large-scale) path planning for robotic vehicles was investigated in three-dimensional space with obstacles, accounting for: (1) energy costs proportional to path length; (2) turn costs where paths change trajectory abruptly; and (3) safety costs for the danger associated with traversing a particular path due to visibility or invisibility from a fixed set of observers. Paths optimal with respect to these cost factors are found. Autonomous or semi-autonomous vehicles were considered operating either in a space environment around satellites and space platforms, or aircraft, spacecraft, or smart missiles operating just above lunar and planetary surfaces. One class of applications concerns minimizing detection, as for example determining the best way to make complex modifications to a satellite without being observed by hostile sensors; another example is verifying there are no paths (holes) through a space defense system. Another class of applications concerns maximizing detection, as finding a good trajectory between mountain ranges of a planet while staying reasonably close to the surface, or finding paths for a flight between two locations that maximize the average number of triangulation points available at any time along the path.

Modeling and Characterization of Near-Crack-Tip Plasticity from Micro- to Nano-Scales

NASA Technical Reports Server (NTRS)

Glaessgen, Edward H.; Saether, Erik; Hochhalter, Jacob; Smith, Stephen W.; Ransom, Jonathan B.; Yamakov, Vesselin; Gupta, Vipul

2010-01-01

Methodologies for understanding the plastic deformation mechanisms related to crack propagation at the nano-, meso- and micro-length scales are being developed. These efforts include the development and application of several computational methods including atomistic simulation, discrete dislocation plasticity, strain gradient plasticity and crystal plasticity; and experimental methods including electron backscattered diffraction and video image correlation. Additionally, methodologies for multi-scale modeling and characterization that can be used to bridge the relevant length scales from nanometers to millimeters are being developed. The paper focuses on the discussion of newly developed methodologies in these areas and their application to understanding damage processes in aluminum and its alloys.

Modeling and Characterization of Near-Crack-Tip Plasticity from Micro- to Nano-Scales

NASA Technical Reports Server (NTRS)

Glaessgen, Edward H.; Saether, Erik; Hochhalter, Jacob; Smith, Stephen W.; Ransom, Jonathan B.; Yamakov, Vesselin; Gupta, Vipul

2011-01-01

Methodologies for understanding the plastic deformation mechanisms related 10 crack propagation at the nano, meso- and micro-length scales are being developed. These efforts include the development and application of several computational methods including atomistic simulation, discrete dislocation plasticity, strain gradient plasticity and crystal plasticity; and experimental methods including electron backscattered diffraction and video image correlation. Additionally, methodologies for multi-scale modeling and characterization that can be used to bridge the relevant length scales from nanometers to millimeters are being developed. The paper focuses on the discussion of newly developed methodologies in these areas and their application to understanding damage processes in aluminum and its alloys.

Electroless Deposition and Nanolithography Can Control the Formation of Materials at the Nano-Scale for Plasmonic Applications

PubMed Central

Coluccio, Maria Laura; Gentile, Francesco; Francardi, Marco; Perozziello, Gerardo; Malara, Natalia; Candeloro, Patrizio; Di Fabrizio, Enzo

2014-01-01

The new revolution in materials science is being driven by our ability to manipulate matter at the molecular level to create structures with novel functions and properties. The aim of this paper is to explore new strategies to obtain plasmonic metal nanostructures through the combination of a top down method, that is electron beam lithography, and a bottom up technique, that is the chemical electroless deposition. This technique allows a tight control over the shape and size of bi- and three-dimensional metal patterns at the nano scale. The resulting nanostructures can be used as constituents of Surface Enhanced Raman Spectroscopy (SERS) substrates, where the electromagnetic field is strongly amplified. Our results indicate that, in electroless growth, high quality metal nanostructures with sizes below 50 nm may be easily obtained. These findings were explained within the framework of a diffusion limited aggregation (DLA) model, that is a simulation model that makes it possible to decipher, at an atomic level, the rules governing the evolution of the growth front; moreover, we give a description of the physical mechanisms of growth at a basic level. In the discussion, we show how these findings can be utilized to fabricate dimers of silver nanospheres where the size and shape of those spheres is controlled with extreme precision and can be used for very large area SERS substrates and nano-optics, for single molecule detection. PMID:24681672

Fast-switching optically isotropic liquid crystal nano-droplets with improved depolarization and Kerr effect by doping high k nanoparticles.

PubMed

Kim, Byeonggon; Kim, Hyun Gyu; Shim, Gyu-Yeop; Park, Ji-Sub; Joo, Kyung-Il; Lee, Dong-Jin; Lee, Joun-Ho; Baek, Ji-Ho; Kim, Byeong Koo; Choi, Yoonseuk; Kim, Hak-Rin

2018-01-10

We proposed and analyzed an optically isotropic nano-droplet liquid crystal (LC) doped with high k nanoparticles (NPs), exhibiting enhanced Kerr effects, which could be operated with reduced driving voltages. For enhancing the contrast ratio together with the light efficiencies, the LC droplet sizes were adjusted to be shorter than the wavelength of visible light to reduce depolarization effects by optical scattering of the LC droplets. Based on the optical analysis of the depolarization effects, the influence of the relationship between the LC droplet size and the NP doping ratio on the Kerr effect change was investigated.

Quadratic Electro-Optic Effect and Electroabsorption in a Novel Nano-Optical Material based on the Nonconjugated Conductive Polymer, Poly(ethylenepyrrolediyl) Derivative

NASA Astrophysics Data System (ADS)

Swamy, R.; Vippa, P.; Rajagopalan, H.; Titus, J.; Thakur, M.; Sen, A.

2005-03-01

We report quadratic electro-optic effect and electroabsorption measurements in a novel nano-optical material based on the nonconjugated conductive polymer, iodine-doped poly(ethylenepyrrolediyl) derivative. Such effect has been recently reported in doped polyisoprene [1]. The measurement was made at 633 nm using field-induced birefringence. A modulation of 0.1% was observed for a field of 0.66 V/micron (film thickness 0.3 micron). The change in refractive index, δn, is 3.35x10-4 and the Kerr constant is 1.2x10-9 m/V^2 which is about 125 times that of nitrobenzene. Modulation due to electroabsorption was 0.05%. The exceptionally large electro-optic effect is most likely due to the specific structure and quantum confinement within a nanometer volume. In contrast, nonlinearity in a conjugated polymer is known to decrease upon iodine doping. [1] Thakur, Swamy and Titus, Macromolecules, Vol.37, 2677, (2004).

Large-scale phase separation with nano-twin domains in manganite spinel (Co,Fe,Mn){sub 3}O{sub 4}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Horibe, Y., E-mail: horibe@post.matsc.kyutech.ac.jp; Takeyama, S.; Mori, S.

The effect of Mn concentration on the formation of nano-domain structures in the spinel oxide (Co,Fe,Mn){sub 3}O{sub 4} was investigated by electron diffraction, bright-, and dark-field imaging technique with transmission electron microscopy. Large scale phase separation with nano-twin domains was observed in Co{sub 0.6}Fe{sub 1.0}Mn{sub 1.4}O{sub 4}, in contrast to the highly aligned checkerboard nano-domains in Co{sub 0.6}Fe{sub 0.9}Mn{sub 1.5}O{sub 4}. Diffusion of the Mn{sup 3+} ions with the Jahn-Teller distortions is suggested to play an important role in the formation of checkerboard nano-domain structure.

Direct Simulations of Coupled Transport and Reaction on Nano-Scale X-Ray Computed Tomography Images of Platinum Group Metal-Free Catalyst Cathodes

DOE PAGES

Ogawa, S.; Komini Babu, S.; Chung, H. T.; ...

2016-08-22

The nano/micro-scale geometry of polymer electrolyte fuel cell (PEFC) catalyst layers critically affects cell performance. The small length scales and complex structure of these composite layers make it challenging to analyze cell performance and physics at the particle scale by experiment. We present a computational method to simulate transport and chemical reaction phenomena at the pore/particle-scale and apply it to a PEFC cathode with platinum group metal free (PGM-free) catalyst. Here, we numerically solve the governing equations for the physics with heterogeneous oxygen diffusion coefficient and proton conductivity evaluated using the actual electrode structure and ionomer distribution obtained using nano-scalemore » resolution X-ray computed tomography (nano-CT). Using this approach, the oxygen concentration and electrolyte potential distributions imposed by the oxygen reduction reaction are solved and the impact of the catalyst layer structure on performance is evaluated.« less

Direct Simulations of Coupled Transport and Reaction on Nano-Scale X-Ray Computed Tomography Images of Platinum Group Metal-Free Catalyst Cathodes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ogawa, S.; Komini Babu, S.; Chung, H. T.

The nano/micro-scale geometry of polymer electrolyte fuel cell (PEFC) catalyst layers critically affects cell performance. The small length scales and complex structure of these composite layers make it challenging to analyze cell performance and physics at the particle scale by experiment. We present a computational method to simulate transport and chemical reaction phenomena at the pore/particle-scale and apply it to a PEFC cathode with platinum group metal free (PGM-free) catalyst. Here, we numerically solve the governing equations for the physics with heterogeneous oxygen diffusion coefficient and proton conductivity evaluated using the actual electrode structure and ionomer distribution obtained using nano-scalemore » resolution X-ray computed tomography (nano-CT). Using this approach, the oxygen concentration and electrolyte potential distributions imposed by the oxygen reduction reaction are solved and the impact of the catalyst layer structure on performance is evaluated.« less

Nano-Scale Characterization of Al-Mg Nanocrystalline Alloys

NASA Astrophysics Data System (ADS)

Harvey, Evan; Ladani, Leila

Materials with nano-scale microstructure have become increasingly popular due to their benefit of substantially increased strengths. The increase in strength as a result of decreasing grain size is defined by the Hall-Petch equation. With increased interest in miniaturization of components, methods of mechanical characterization of small volumes of material are necessary because traditional means such as tensile testing becomes increasingly difficult with such small test specimens. This study seeks to characterize elastic-plastic properties of nanocrystalline Al-5083 through nanoindentation and related data analysis techniques. By using nanoindentation, accurate predictions of the elastic modulus and hardness of the alloy were attained. Also, the employed data analysis model provided reasonable estimates of the plastic properties (strain-hardening exponent and yield stress) lending credibility to this procedure as an accurate, full mechanical characterization method.

Reduced wear of enamel with novel fine and nano-scale leucite glass-ceramics.

PubMed

Theocharopoulos, Antonios; Chen, Xiaohui; Hill, Robert; Cattell, Michael J

2013-06-01

Leucite glass-ceramics used to produce all-ceramic restorations can suffer from brittle fracture and wear the opposing teeth. High strength and fine crystal sized leucite glass-ceramics have recently been reported. The objective of this study is to investigate whether fine and nano-scale leucite glass-ceramics with minimal matrix microcracking are associated with a reduction in in vitro tooth wear. Human molar cusps (n=12) were wear tested using a Bionix-858 testing machine (300,000 simulated masticatory cycles) against experimental fine crystal sized (FS), nano-scale crystal sized (NS) leucite glass-ceramics and a commercial leucite glass-ceramic (Ceramco-3, Dentsply, USA). Wear was imaged using Secondary Electron Imaging (SEI) and quantified using white-light profilometry. Both experimental groups were found to produce significantly (p<0.05) less volume and mean-height tooth loss compared to Ceramco-3. The NS group had significantly (p<0.05) less tooth mean-height loss and less combined (tooth and ceramic) loss than the FS group. Increased waviness and damage was observed on the wear surfaces of the Ceramco-3 glass-ceramic disc/tooth group in comparison to the experimental groups. This was also indicated by higher surface roughness values for the Ceramco-3 glass-ceramic disc/tooth group. Fine and nano-sized leucite glass-ceramics produced a reduction in in vitro tooth wear. The high strength low wear materials of this study may help address the many problems associated with tooth enamel wear and restoration failure. Copyright © 2013 Elsevier Ltd. All rights reserved.

Optical Coherence Elastography

NASA Astrophysics Data System (ADS)

Kennedy, Brendan F.; Kennedy, Kelsey M.; Oldenburg, Amy L.; Adie, Steven G.; Boppart, Stephen A.; Sampson, David D.

The mechanical properties of tissue are pivotal in its function and behavior, and are often modified by disease. From the nano- to the macro-scale, many tools have been developed to measure tissue mechanical properties, both to understand the contribution of mechanics in the origin of disease and to improve diagnosis. Optical coherence elastography is applicable to the intermediate scale, between that of cells and whole organs, which is critical in the progression of many diseases and not widely studied to date. In optical coherence elastography, a mechanical load is imparted to a tissue and the resulting deformation is measured using optical coherence tomography. The deformation is used to deduce a mechanical parameter, e.g., Young's modulus, which is mapped into an image, known as an elastogram. In this chapter, we review the development of optical coherence elastography and report on the latest developments. We provide a focus on the underlying principles and assumptions, techniques to measure deformation, loading mechanisms, imaging probes and modeling, including the inverse elasticity problem.

Nano-Scale Sample Acquisition Systems for Small Class Exploration Spacecraft

NASA Astrophysics Data System (ADS)

Paulsen, G.

2015-12-01

The paradigm for space exploration is changing. Large and expensive missions are very rare and the space community is turning to smaller, lighter, and less expensive missions that could still perform great exploration. These missions are also within reach of commercial companies such as the Google Lunar X Prize teams that develop small scale lunar missions. Recent commercial endeavors such as "Planet Labs inc." and Sky Box Imaging, inc. show that there are new benefits and business models associated with miniaturization of space hardware. The Nano-Scale Sample Acquisition System includes NanoDrill for capture of small rock cores and PlanetVac for capture of surface regolith. These two systems are part of the ongoing effort to develop "Micro Sampling" systems for deployment by the small spacecraft with limited payload capacities. The ideal applications include prospecting missions to the Moon and Asteroids. The MicroDrill is a rotary-percussive coring drill that captures cores 7 mm in diameter and up to 2 cm long. The drill weighs less than 1 kg and can capture a core from a 40 MPa strength rock within a few minutes, with less than 10 Watt power and less than 10 Newton of preload. The PlanetVac is a pneumatic based regolith acquisition system that can capture surface sample in touch-and-go maneuver. These sampling systems were integrated within the footpads of commercial quadcopter for testing. As such, they could also be used by geologists on Earth to explore difficult to get to locations.

Nano/microstructure and optical properties of ZnO particles precipitated from zinc acetylacetonate

NASA Astrophysics Data System (ADS)

Petrović, Željka; Ristić, Mira; Musić, Svetozar; Fabián, Martin

2015-06-01

The influence of experimental conditions on the nano/microstructure and optical properties of ZnO particles produced by rapid hydrolysis of zinc acetylacetonate, followed by aging of the precipitation system at 160 °C, was investigated. Samples were characterized by XRD, FE scanning electron microscopy (FE-SEM), FT-IR, UV/Vis/NIR and photoluminescence (PL) spectroscopies. XRD patterns of all samples were assigned to the hexagonal ZnO phase (wurtzite-type), as well as the corresponding FT-IR spectra. FE-SEM inspection showed a high dependence of the ZnO nano/microstructure on the chemical composition of the reaction mixture and autoclaving time after the rapid hydrolysis of zinc acetylacetonate. Microstructural differences were noticed between C2H5OH/H2O and H2O media, as well as under the influence of NH4OH addition. Measurements of nanocrystallite sizes showed no significant preferential orientation in the (1 0 0) and (0 0 2) directions relative to the (1 0 1) and (1 1 0) directions. Somewhat smaller crystallite sizes were noticed for ZnO samples synthesized by adding the NH4OH solution. Dissolution/recrystallization of ZnO particles played an important role in the formation of different ZnO nano/microstructures. The band gap values for prepared ZnO samples were calculated on the basis of recorded UV/Vis spectra. PL spectra were recorded for ZnO samples in powder form and their suspensions in pure ethanol. Noticed differences are discussed.

Advanced Ceramics from Preceramic Polymers Modified at the Nano-Scale: A Review.

PubMed

Bernardo, Enrico; Fiocco, Laura; Parcianello, Giulio; Storti, Enrico; Colombo, Paolo

2014-03-06

Preceramic polymers, i.e. , polymers that are converted into ceramics upon heat treatment, have been successfully used for almost 40 years to give advanced ceramics, especially belonging to the ternary SiCO and SiCN systems or to the quaternary SiBCN system. One of their main advantages is the possibility of combining the shaping and synthesis of ceramics: components can be shaped at the precursor stage by conventional plastic-forming techniques, such as spinning, blowing, injection molding, warm pressing and resin transfer molding, and then converted into ceramics by treatments typically above 800 °C. The extension of the approach to a wider range of ceramic compositions and applications, both structural and thermo-structural (refractory components, thermal barrier coatings) or functional (bioactive ceramics, luminescent materials), mainly relies on modifications of the polymers at the nano-scale, i.e. , on the introduction of nano-sized fillers and/or chemical additives, leading to nano-structured ceramic components upon thermal conversion. Fillers and additives may react with the main ceramic residue of the polymer, leading to ceramics of significant engineering interest (such as silicates and SiAlONs), or cause the formation of secondary phases, significantly affecting the functionalities of the polymer-derived matrix.

Advanced Ceramics from Preceramic Polymers Modified at the Nano-Scale: A Review

PubMed Central

Bernardo, Enrico; Fiocco, Laura; Parcianello, Giulio; Storti, Enrico; Colombo, Paolo

2014-01-01

Preceramic polymers, i.e., polymers that are converted into ceramics upon heat treatment, have been successfully used for almost 40 years to give advanced ceramics, especially belonging to the ternary SiCO and SiCN systems or to the quaternary SiBCN system. One of their main advantages is the possibility of combining the shaping and synthesis of ceramics: components can be shaped at the precursor stage by conventional plastic-forming techniques, such as spinning, blowing, injection molding, warm pressing and resin transfer molding, and then converted into ceramics by treatments typically above 800 °C. The extension of the approach to a wider range of ceramic compositions and applications, both structural and thermo-structural (refractory components, thermal barrier coatings) or functional (bioactive ceramics, luminescent materials), mainly relies on modifications of the polymers at the nano-scale, i.e., on the introduction of nano-sized fillers and/or chemical additives, leading to nano-structured ceramic components upon thermal conversion. Fillers and additives may react with the main ceramic residue of the polymer, leading to ceramics of significant engineering interest (such as silicates and SiAlONs), or cause the formation of secondary phases, significantly affecting the functionalities of the polymer-derived matrix. PMID:28788548

Three-dimensional micro/nano-scale structure fabricated by combination of non-volatile polymerizable RTIL and FIB irradiation

PubMed Central

Kuwabata, Susumu; Minamimoto, Hiro; Inoue, Kosuke; Imanishi, Akihito; Hosoya, Ken; Uyama, Hiroshi; Torimoto, Tsukasa; Tsuda, Tetsuya; Seki, Shu

2014-01-01

Room-temperature ionic liquid (RTIL) has been widely investigated as a nonvolatile solvent as well as a unique liquid material because of its interesting features, e.g., negligible vapor pressure and high thermal stability. Here we report that a non-volatile polymerizable RTIL is a useful starting material for the fabrication of micro/nano-scale polymer structures with a focused-ion-beam (FIB) system operated under high-vacuum condition. Gallium-ion beam irradiation to the polymerizable 1-allyl-3-ethylimidazolium bis((trifluoromethane)sulfonyl)amide RTIL layer spread on a Si wafer induced a polymerization reaction without difficulty. What is interesting to note is that we have succeeded in provoking the polymerization reaction anywhere on the Si wafer substrate by using FIB irradiation with a raster scanning mode. By this finding, two- and three-dimensional micro/nano-scale polymer structure fabrications were possible at the resolution of 500,000 dpi. Even intricate three-dimensional micro/nano-figures with overhang and hollow moieties could be constructed at the resolution of approximately 100 nm. PMID:24430465

Evaluation of Acoustic Propagation Paths into the Human Head

DTIC Science & Technology

2005-04-01

pressure amplitude) via the alternate propagation paths. A 3D finite-element solid mesh was constructed using a digital image database of an adult...optics, rays are used to depict the path or paths taken as a light wave travels through a lens. However, in optics, the eikonal equation can be solved

Optical interconnect for large-scale systems

NASA Astrophysics Data System (ADS)

Dress, William

2013-02-01

This paper presents a switchless, optical interconnect module that serves as a node in a network of identical distribution modules for large-scale systems. Thousands to millions of hosts or endpoints may be interconnected by a network of such modules, avoiding the need for multi-level switches. Several common network topologies are reviewed and their scaling properties assessed. The concept of message-flow routing is discussed in conjunction with the unique properties enabled by the optical distribution module where it is shown how top-down software control (global routing tables, spanning-tree algorithms) may be avoided.

Computing fluid-particle interaction forces for nano-suspension droplet spreading: molecular dynamics simulations

NASA Astrophysics Data System (ADS)

Zhou, Weizhou; Shi, Baiou; Webb, Edmund

2017-11-01

Recently, there are many experimental and theoretical studies to understand and control the dynamic spreading of nano-suspension droplets on solid surfaces. However, fundamental understanding of driving forces dictating the kinetics of nano-suspension wetting and spreading, especially capillary forces that manifest during the process, is lacking. Here, we present results from atomic scale simulations that were used to compute forces between suspended particles and advancing liquid fronts. The role of nano-particle size, particle loading, and interaction strength on forces computed from simulations will be discussed. Results demonstrate that increasing the particle size dramatically changes observed wetting behavior from depinning to pinning. From simulations on varying particle size, a relationship between computed forces and particle size is advanced and compared to existing expressions in the literature. High particle loading significantly slowed spreading kinetics, by introducing tortuous transport paths for liquid delivery to the advancing contact line. Lastly, we show how weakening the interaction between the particle and the underlying substrate can change a system from exhibiting pinning behavior to de-pinning.

Titanium bone implants with superimposed micro/nano-scale porosity and antibacterial capability

NASA Astrophysics Data System (ADS)

Necula, B. S.; Apachitei, I.; Fratila-Apachitei, L. E.; van Langelaan, E. J.; Duszczyk, J.

2013-05-01

This study aimed at producing a multifunctional layer with micro/nano-interconnected porosity and antibacterial capability on a rough macro-porous plasma sprayed titanium surface using the plasma electrolytic oxidation process. The layers were electrochemically formed in electrolytes based on calcium acetate and calcium glycerophosphate salts bearing dispersed Ag nanoparticles. They were characterized with respect to surface morphology and chemical composition using a scanning electron microscope equipped with the energy dispersive spectroscopy and back scattering detectors. Scanning electron microscopy images showed the formation of a micro/nano-scale porous layer, comprised of TiO2 bearing Ca and P species and Ag nanoparticles, following accurately the surface topography of the plasma sprayed titanium coating. The Ca/P atomic ratio was found to be close to that of bone apatite. Ag nanoparticles were incorporated on both on top and inside the porous structure of the TiO2 layer.

Pressure-induced nano-crystallization of silicate garnets from glass

PubMed Central

Irifune, T.; Kawakami, K.; Arimoto, T.; Ohfuji, H.; Kunimoto, T.; Shinmei, T.

2016-01-01

Transparent ceramics are important for scientific and industrial applications because of the superior optical and mechanical properties. It has been suggested that optical transparency and mechanical strength are substantially enhanced if transparent ceramics with nano-crystals are available. However, synthesis of the highly transparent nano-crystalline ceramics has been difficult using conventional sintering techniques at relatively low pressures. Here we show direct conversion from bulk glass starting material in mutianvil high-pressure apparatus leads to pore-free nano-polycrystalline silicate garnet at pressures above ∼10 GPa in a limited temperature range around 1,400 °C. The synthesized nano-polycrystalline garnet is optically as transparent as the single crystal for almost the entire visible light range and harder than the single crystal by ∼30%. The ultrahigh-pressure conversion technique should provide novel functional ceramics having various crystal structures, including those of high-pressure phases, as well as ideal specimens for some mineral physics applications. PMID:27924866

Robot-assisted three-dimensional registration for cochlear implant surgery using a common-path swept-source optical coherence tomography probe

NASA Astrophysics Data System (ADS)

Gurbani, Saumya S.; Wilkening, Paul; Zhao, Mingtao; Gonenc, Berk; Cheon, Gyeong Woo; Iordachita, Iulian I.; Chien, Wade; Taylor, Russell H.; Niparko, John K.; Kang, Jin U.

2014-05-01

Cochlear implantation offers the potential to restore sensitive hearing in patients with severe to profound deafness. However, surgical placement of the electrode array within the cochlea can produce trauma to sensorineural components, particularly if the initial turn of the cochlea is not successfully navigated as the array is advanced. In this work, we present a robot-mounted common-path swept-source optical coherence tomography endoscopic platform for three-dimensional (3-D) optical coherence tomography (OCT) registration and preoperative surgical planning for cochlear implant surgery. The platform is composed of a common-path 600-μm diameter fiber optic rotary probe attached to a five degrees of freedom robot capable of 1 μm precision movement. The system is tested on a dry fixed ex vivo human temporal bone, and we demonstrate the feasibility of a 3-D OCT registration of the cochlea to accurately describe the spatial and angular profiles of the canal formed by the scala tympani into the first cochlear turn.

Optimizing Cr(VI) and Tc(VII) remediation through nano-scale biomineral engineering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cutting, R. S.; Coker, V. S.; Telling, N. D.

2009-09-09

To optimize the production of biomagnetite for the bioremediation of metal oxyanion contaminated waters, the reduction of aqueous Cr(VI) to Cr(III) by two biogenic magnetites and a synthetic magnetite was evaluated under batch and continuous flow conditions. Results indicate that nano-scale biogenic magnetite produced by incubating synthetic schwertmannite powder in cell suspensions of Geobacter sulfurreducens is more efficient at reducing Cr(VI) than either biogenic nano-magnetite produced from a suspension of ferrihydrite 'gel' or synthetic nano-scale Fe{sub 3}O{sub 4} powder. Although X-ray Photoelectron Spectroscopy (XPS) measurements obtained from post-exposure magnetite samples reveal that both Cr(III) and Cr(VI) are associated with nanoparticlemore » surfaces, X-ray Magnetic Circular Dichroism (XMCD) studies indicate that some Cr(III) has replaced octahedrally coordinated Fe in the lattice of the magnetite. Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) measurements of total aqueous Cr in the associated solution phase indicated that, although the majority of Cr(III) was incorporated within or adsorbed to the magnetite samples, a proportion ({approx}10-15 %) was released back into solution. Studies of Tc(VII) uptake by magnetites produced via the different synthesis routes also revealed significant differences between them as regards effectiveness for remediation. In addition, column studies using a {gamma}-camera to obtain real time images of a {sup 99m}Tc(VII) radiotracer were performed to visualize directly the relative performances of the magnetite sorbents against ultra-trace concentrations of metal oxyanion contaminants. Again, the magnetite produced from schwertmannite proved capable of retaining more ({approx}20%) {sup 99m}Tc(VII) than the magnetite produced from ferrihydrite, confirming that biomagnetite production for efficient environmental remediation can be fine-tuned through careful selection of the initial Fe(III) mineral

Multi-scale analysis of the effect of nano-filler particle diameter on the physical properties of CAD/CAM composite resin blocks.

PubMed

Yamaguchi, Satoshi; Inoue, Sayuri; Sakai, Takahiko; Abe, Tomohiro; Kitagawa, Haruaki; Imazato, Satoshi

2017-05-01

The objective of this study was to assess the effect of silica nano-filler particle diameters in a computer-aided design/manufacturing (CAD/CAM) composite resin (CR) block on physical properties at the multi-scale in silico. CAD/CAM CR blocks were modeled, consisting of silica nano-filler particles (20, 40, 60, 80, and 100 nm) and matrix (Bis-GMA/TEGDMA), with filler volume contents of 55.161%. Calculation of Young's moduli and Poisson's ratios for the block at macro-scale were analyzed by homogenization. Macro-scale CAD/CAM CR blocks (3 × 3 × 3 mm) were modeled and compressive strengths were defined when the fracture loads exceeded 6075 N. MPS values of the nano-scale models were compared by localization analysis. As the filler size decreased, Young's moduli and compressive strength increased, while Poisson's ratios and MPS decreased. All parameters were significantly correlated with the diameters of the filler particles (Pearson's correlation test, r = -0.949, 0.943, -0.951, 0.976, p < 0.05). The in silico multi-scale model established in this study demonstrates that the Young's moduli, Poisson's ratios, and compressive strengths of CAD/CAM CR blocks can be enhanced by loading silica nanofiller particles of smaller diameter. CAD/CAM CR blocks by using smaller silica nano-filler particles have a potential to increase fracture resistance.

A new front-face optical cell for measuring weak fluorescent emissions with time resolution in the picosecond time scale.

PubMed

Gryczynski, Z; Bucci, E

1993-11-01

Recent developments of ultrafast fluorimeters allow measuring time-resolved fluorescence on the picosecond time scale. This implies one is able to monitor lifetimes and anisotropy decays of highly quenched systems and of systems that contain fluorophores having lifetimes in the subnanosecond range; both systems that emit weak signals. The combination of weak signals and very short lifetimes makes the measurements prone to distortions which are negligible in standard fluorescence experiments. To cope with these difficulties, we have designed a new optical cell for front-face optics which offers to the excitation beam a horizontal free liquid surface in the absence of interactions with optical windows. The new cell has been tested with probes of known lifetimes and anisotropies. It proved very useful in detecting tryptophan fluorescence in hemoglobin. If only diluted samples are available, which cannot be used in front-face optics, regular square geometry can still be utilized by inserting light absorbers into a cuvette of 1 cm path length.

On-chip optical transduction scheme for graphene nano-electro-mechanical systems in silicon-photonic platform.

PubMed

Dash, Aneesh; Selvaraja, S K; Naik, A K

2018-02-15

We present a scheme for on-chip optical transduction of strain and displacement of graphene-based nano-electro-mechanical systems (NEMS). A detailed numerical study on the feasibility of three silicon-photonic integrated circuit configurations is presented: the Mach-Zehnder interferometer (MZI), the micro-ring resonator, and the ring-loaded MZI. An index sensing based technique using an MZI loaded with a ring resonator with a moderate Q-factor of 2400 can yield a sensitivity of 28  fm/Hz and 6.5×10 -6 %/Hz for displacement and strain, respectively. Though any phase-sensitive integrated-photonic device could be used for optical transduction, here we show that optimal sensitivity is achievable by combining resonance with phase sensitivity.

Optical printed circuit board (O-PCB) and VLSI photonic integrated circuits: visions, challenges, and progresses

NASA Astrophysics Data System (ADS)

Lee, El-Hang; Lee, S. G.; O, B. H.; Park, S. G.; Noh, H. S.; Kim, K. H.; Song, S. H.

2006-09-01

A collective overview and review is presented on the original work conducted on the theory, design, fabrication, and in-tegration of micro/nano-scale optical wires and photonic devices for applications in a newly-conceived photonic systems called "optical printed circuit board" (O-PCBs) and "VLSI photonic integrated circuits" (VLSI-PIC). These are aimed for compact, high-speed, multi-functional, intelligent, light-weight, low-energy and environmentally friendly, low-cost, and high-volume applications to complement or surpass the capabilities of electrical PCBs (E-PCBs) and/or VLSI electronic integrated circuit (VLSI-IC) systems. These consist of 2-dimensional or 3-dimensional planar arrays of micro/nano-optical wires and circuits to perform the functions of all-optical sensing, storing, transporting, processing, switching, routing and distributing optical signals on flat modular boards or substrates. The integrated optical devices include micro/nano-scale waveguides, lasers, detectors, switches, sensors, directional couplers, multi-mode interference devices, ring-resonators, photonic crystal devices, plasmonic devices, and quantum devices, made of polymer, silicon and other semiconductor materials. For VLSI photonic integration, photonic crystals and plasmonic structures have been used. Scientific and technological issues concerning the processes of miniaturization, interconnection and integration of these systems as applicable to board-to-board, chip-to-chip, and intra-chip integration, are discussed along with applications for future computers, telecommunications, and sensor-systems. Visions and challenges toward these goals are also discussed.

Active control of nano dimers response using piezoelectric effect

NASA Astrophysics Data System (ADS)

Mekkawy, Ahmed A.; Ali, Tamer A.; Badawi, Ashraf H.

2016-09-01

Nano devices can be used as building blocks for Internet of Nano-Things network devices, such as sensors/actuators, transceivers, and routers. Although nano particles response can be engineered to fit in different regimes, for such a nano particle to be used as an active nano device, its properties should be dynamically controlled. This controllability is a challenge, and there are many proposed techniques to tune nanoparticle response on the spot through a sort of control signal, wither that signal is optical (for all-optical systems) or electronic (for opto-electronic systems). This will allow the use of nano particles as nano-switches or as dynamic sensors that can pick different frequencies depending on surrounding conditions or depending on a smart decisions. In this work, we propose a piezoelectric substrate as an active control mediator to control plasmonic gaps in nano dimers. This method allows for integrating nano devices with regular electronics while communicating control signals to nano devices through applying electric signals to a piezoelectric material, in order to control the gaps between nano particles in a nano cluster. We do a full numerical study to the system, analyzing the piezoelectric control resolution (minimum gap change step) and its effect on a nanodimer response as a nanoantenna. This analysis considers the dielectric functions of materials within the visible frequencies range. The effects of different parameters, such as the piezoelectric geometrical structure and materials, on the gap control resolution and the operating frequency are studied.

Folded path LWIR system for SWAP constrained platforms

NASA Astrophysics Data System (ADS)

Fleet, Erin F.; Wilson, Michael L.; Linne von Berg, Dale; Giallorenzi, Thomas; Mathieu, Barry

2014-06-01

Folded path reflection and catadioptric optics are of growing interest, especially in the long wave infrared (LWIR), due to continuing demands for reductions in imaging system size, weight and power (SWAP). We present the optical design and laboratory data for a 50 mm focal length low f/# folded-path compact LWIR imaging system. The optical design uses 4 concentric aspheric mirrors, each of which is described by annular aspheric functions well suited to the folded path design space. The 4 mirrors are diamond turned onto two thin air-spaced aluminum plates which can be manually focused onto the uncooled LWIR microbolometer array detector. Stray light analysis will be presented to show how specialized internal baffling can be used to reduce stray light propagation through the folded path optical train. The system achieves near diffraction limited performance across the FOV with a 15 mm long optical train and a 5 mm back focal distance. The completed system is small enough to reside within a 3 inch diameter ball gimbal.

Micro- and nano-scale characterization to study the thermal degradation of cement-based materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lim, Seungmin, E-mail: lim76@illinois.edu; Mondal, Paramita

2014-06-01

The degradation of hydration products of cement is known to cause changes in the micro- and nano-structure, which ultimately drive thermo-mechanical degradation of cement-based composite materials at elevated temperatures. However, a detailed characterization of these changes is still incomplete. This paper presents results of an extensive experimental study carried out to investigate micro- and nano-structural changes that occur due to exposure of cement paste to high temperatures. Following heat treatment of cement paste up to 1000 °C, damage states were studied by compressive strength test, thermogravimetric analysis (TGA), scanning electron microscopy (SEM) atomic force microscopy (AFM) and AFM image analysis.more » Using experimental results and research from existing literature, new degradation processes that drive the loss of mechanical properties of cement paste are proposed. The development of micro-cracks at the interface between unhydrated cement particles and paste matrix, a change in C–S–H nano-structure and shrinkage of C–S–H, are considered as important factors that cause the thermal degradation of cement paste. - Highlights: • The thermal degradation of hydration products of cement is characterized at micro- and nano-scale using scanning electron microscopy (SEM) and atomic force microscopy (AFM). • The interface between unhydrated cement particles and the paste matrix is considered the origin of micro-cracks. • When cement paste is exposed to temperatures above 300 ºC, the nano-structure of C-S-H becomes a more loosely packed globular structure, which could be indicative of C-S-H shrinkage.« less

[Preparation of nano-nacre artificial bone].

PubMed

Chen, Jian-ting; Tang, Yong-zhi; Zhang, Jian-gang; Wang, Jian-jun; Xiao, Ying

2008-12-01

To assess the improvements in the properties of nano-nacre artificial bone prepared on the basis of nacre/polylactide acid composite artificial bone and its potential for clinical use. The compound of nano-scale nacre powder and poly-D, L-lactide acid (PDLLA) was used to prepare the cylindrical hollow artificial bone, whose properties including raw material powder scale, pore size, porosity and biomechanical characteristics were compared with another artificial bone made of micron-scale nacre powder and PDLLA. Scanning electron microscope showed that the average particle size of the nano-nacre powder was 50.4-/+12.4 nm, and the average pore size of the artificial bone prepared using nano-nacre powder was 215.7-/+77.5 microm, as compared with the particle size of the micron-scale nacre powder of 5.0-/+3.0 microm and the pore size of the resultant artificial bone of 205.1-/+72.0 microm. The porosities of nano-nacre artificial bone and the micron-nacre artificial bone were (65.4-/+2.9)% and (53.4-/+2.2)%, respectively, and the two artificial bones had comparable compressive strength and Young's modulus, but the flexural strength of the nano-nacre artificial bone was lower than that of the micro-nacre artificial bone. The nano-nacre artificial bone allows better biodegradability and possesses appropriate pore size, porosity and biomechanical properties for use as a promising material in bone tissue engineering.

Automatic alignment of double optical paths in excimer laser amplifier

NASA Astrophysics Data System (ADS)

Wang, Dahui; Zhao, Xueqing; Hua, Hengqi; Zhang, Yongsheng; Hu, Yun; Yi, Aiping; Zhao, Jun

2013-05-01

A kind of beam automatic alignment method used for double paths amplification in the electron pumped excimer laser system is demonstrated. In this way, the beams from the amplifiers can be transferred along the designated direction and accordingly irradiate on the target with high stabilization and accuracy. However, owing to nonexistence of natural alignment references in excimer laser amplifiers, two cross-hairs structure is used to align the beams. Here, one crosshair put into the input beam is regarded as the near-field reference while the other put into output beam is regarded as the far-field reference. The two cross-hairs are transmitted onto Charge Coupled Devices (CCD) by image-relaying structures separately. The errors between intersection points of two cross-talk images and centroid coordinates of actual beam are recorded automatically and sent to closed loop feedback control mechanism. Negative feedback keeps running until preset accuracy is reached. On the basis of above-mentioned design, the alignment optical path is built and the software is compiled, whereafter the experiment of double paths automatic alignment in electron pumped excimer laser amplifier is carried through. Meanwhile, the related influencing factors and the alignment precision are analyzed. Experimental results indicate that the alignment system can achieve the aiming direction of automatic aligning beams in short time. The analysis shows that the accuracy of alignment system is 0.63μrad and the beam maximum restoration error is 13.75μm. Furthermore, the bigger distance between the two cross-hairs, the higher precision of the system is. Therefore, the automatic alignment system has been used in angular multiplexing excimer Main Oscillation Power Amplification (MOPA) system and can satisfy the requirement of beam alignment precision on the whole.

A compact thermo-optical multimode-interference silicon-based 1 × 4 nano-photonic switch.

PubMed

Zhou, Haifeng; Song, Junfeng; Chee, Edward K S; Li, Chao; Zhang, Huijuan; Lo, Guoqiang

2013-09-09

An ultra-compact multimode-interference (MMI)-based 1 × 4 nano-photonic switch is demonstrated by employing silicon thermo-optical effect on SOI platform. The device performance is systematically characterized by comprehensively investigating the constituent building blocks, including 1 × 4 power splitter, 4 × 4 MMI coupler and groove-isolated thermo-optical heaters. An instructive model is established to statistically estimate the required power consumption and investigate the influence of the power imbalance of the 4 × 4 MMI coupler on the switching performance. At the designed wavelength of 1550 nm, the average insertion loss of different switching states is 1.7 dB, and the transmission imbalance is 1.05 dB. The worst extinction ratio and crosstalk of all the output ports reach 11.48 dB and -11.38 dB, respectively.

A new multiscale model to describe a modified Hall-Petch relation at different scales for nano and micro materials

NASA Astrophysics Data System (ADS)

Fadhil, Sadeem Abbas; Alrawi, Aoday Hashim; Azeez, Jazeel H.; Hassan, Mohsen A.

2018-04-01

In the present work, a multiscale model is presented and used to modify the Hall-Petch relation for different scales from nano to micro. The modified Hall-Petch relation is derived from a multiscale equation that determines the cohesive energy between the atoms and their neighboring grains. This brings with it a new term that was originally ignored even in the atomistic models. The new term makes it easy to combine all other effects to derive one modified equation for the Hall-Petch relation that works for all scales together, without the need to divide the scales into two scales, each scale with a different equation, as it is usually done in other works. Due to that, applying the new relation does not require a previous knowledge of the grain size distribution. This makes the new derived relation more consistent and easier to be applied for all scales. The new relation is used to fit the data for Copper and Nickel and it is applied well for the whole range of grain sizes from nano to micro scales.

Toward giga-pixel nanoscopy on a chip: a computational wide-field look at the nano-scale without the use of lenses.

PubMed

McLeod, Euan; Luo, Wei; Mudanyali, Onur; Greenbaum, Alon; Ozcan, Aydogan

2013-06-07

The development of lensfree on-chip microscopy in the past decade has opened up various new possibilities for biomedical imaging across ultra-large fields of view using compact, portable, and cost-effective devices. However, until recently, its ability to resolve fine features and detect ultra-small particles has not rivalled the capabilities of the more expensive and bulky laboratory-grade optical microscopes. In this Frontier Review, we highlight the developments over the last two years that have enabled computational lensfree holographic on-chip microscopy to compete with and, in some cases, surpass conventional bright-field microscopy in its ability to image nano-scale objects across large fields of view, yielding giga-pixel phase and amplitude images. Lensfree microscopy has now achieved a numerical aperture as high as 0.92, with a spatial resolution as small as 225 nm across a large field of view e.g., >20 mm(2). Furthermore, the combination of lensfree microscopy with self-assembled nanolenses, forming nano-catenoid minimal surfaces around individual nanoparticles has boosted the image contrast to levels high enough to permit bright-field imaging of individual particles smaller than 100 nm. These capabilities support a number of new applications, including, for example, the detection and sizing of individual virus particles using field-portable computational on-chip microscopes.

Multidimensional scaling for evolutionary algorithms--visualization of the path through search space and solution space using Sammon mapping.

PubMed

Pohlheim, Hartmut

2006-01-01

Multidimensional scaling as a technique for the presentation of high-dimensional data with standard visualization techniques is presented. The technique used is often known as Sammon mapping. We explain the mathematical foundations of multidimensional scaling and its robust calculation. We also demonstrate the use of this technique in the area of evolutionary algorithms. First, we present the visualization of the path through the search space of the best individuals during an optimization run. We then apply multidimensional scaling to the comparison of multiple runs regarding the variables of individuals and multi-criteria objective values (path through the solution space).

Characteristic Behavior and Scaling Studies of Self Organized InP Nano-dots formed via keV and MeV irradiations

NASA Astrophysics Data System (ADS)

Paramanik, Dipak; Varma, Shikha

2008-04-01

The controlled formation of nano-dots, using ion beams as tool, has become important as it offers a unique method to generate non-equilibrium phases with novel physical properties and structures with nano-dimensions. We have investigated the creation of self assembled nano- dots on InP(111) surfaces after 3 keV as well as 1.5 MeV ion beams at a large range of fluences. We have studied the Scaling exponents of the evolved surfaces by utilizing the technique of Scanning Probe Microscopy (SPM). At keV energies ripening of the nano-dots is seen below a critical time whereas an inverse ripening is observed for longer durations. At the critical time square shaped array of nano --dots are observed. The dots are characterized by narrow height and size distributions. Nano dots have also been observed at MeV ion irradiations. Their size distribution though broad at lowest fluence decreases for larger fluences.

Design of a sector bowtie nano-rectenna for optical power and infrared detection

NASA Astrophysics Data System (ADS)

Wang, Kai; Hu, Haifeng; Lu, Shan; Guo, Lingju; He, Tao

2015-10-01

We designed a sector bowtie nanoantenna integrated with a rectifier (Au-TiO x -Ti diode) for collecting infrared energy. The optical performance of the metallic bowtie nanoantenna was numerically investigated at infrared frequencies (5-30 μm) using three-dimensional frequency-domain electromagnetic field calculation software based on the finite element method. The simulation results indicate that the resonance wavelength and local field enhancement are greatly affected by the shape and size of the bowtie nanoantenna, as well as the relative permittivity and conductivity of the dielectric layer. The output current of the rectified nano-rectenna is substantially at nanoampere magnitude with an electric field intensity of 1 V/m. Moreover, the power conversion efficiency for devices with three different substrates illustrates that a substrate with a larger refractive index yields a higher efficiency and longer infrared response wavelength. Consequently, the optimized structure can provide theoretical support for the design of novel optical rectennas and fabrication of optoelectronic devices.

Micro- and Nano-scale Diffusion Domains Acting as Kinetic Controls for U(VI) Release to the Hanford 300-Area Aquifer

NASA Astrophysics Data System (ADS)

Stoliker, D. L.; Hay, M. B.; Davis, J. A.; Zachara, J. M.

2008-12-01

The 300-Area of the Hanford reservation, a cold-war era nuclear processing facility, is plagued by long-term elevated concentrations of U(VI) in the underlying aquifer. While the sediment U(VI) concentration is relatively low, it continues to act as a source and sink for the contaminant, allowing for persistent groundwater concentrations well above the maximum contamination limit (MCL). Simple Kd modeling of the attenuation of U(VI) in the aquifer predicted that groundwater U(VI) concentrations would decrease to below the drinking water standard by the year 2002. However, grain-scale morphology of the aquifer material suggests that intra-grain flow paths and mineral coatings, in which sorption complexes and precipitates formed over years of waste disposal, provide a significant kinetic constraint that slows groundwater flushing of the sediments. In order to quantify the impact of diffusion kinetics on the release of U(VI), high-resolution, non-reactive tracer studies were conducted on vadose zone sediments in both column and batch reactors. Systems were equilibrated for long time scales with tritated artificial groundwater and then flushed with flow and stop-flow events included for columns. Previously collected U(VI) release data from batch dissolution/desorption studies is compared with tritium tracer diffusion kinetics as well as porosimetry and detailed microscopy characterization. The micro-scale and nano-scale diffusion regimes, including intra-granular regions as well as mineral coatings, represent a significant potential long-term source of contaminant U(VI). Understanding the physical kinetic limitations coupled with the complex chemistry of U(VI) sorption processes within natural systems is an important step forward in providing information to strengthen field-scale reactive transport simulations.

Linear and ultrafast nonlinear plasmonics of single nano-objects

NASA Astrophysics Data System (ADS)

Crut, Aurélien; Maioli, Paolo; Vallée, Fabrice; Del Fatti, Natalia

2017-03-01

Single-particle optical investigations have greatly improved our understanding of the fundamental properties of nano-objects, avoiding the spurious inhomogeneous effects that affect ensemble experiments. Correlation with high-resolution imaging techniques providing morphological information (e.g. electron microscopy) allows a quantitative interpretation of the optical measurements by means of analytical models and numerical simulations. In this topical review, we first briefly recall the principles underlying some of the most commonly used single-particle optical techniques: near-field, dark-field, spatial modulation and photothermal microscopies/spectroscopies. We then focus on the quantitative investigation of the surface plasmon resonance (SPR) of metallic nano-objects using linear and ultrafast optical techniques. While measured SPR positions and spectral areas are found in good agreement with predictions based on Maxwell’s equations, SPR widths are strongly influenced by quantum confinement (or, from a classical standpoint, surface-induced electron scattering) and, for small nano-objects, cannot be reproduced using the dielectric functions of bulk materials. Linear measurements on single nano-objects (silver nanospheres and gold nanorods) allow a quantification of the size and geometry dependences of these effects in confined metals. Addressing the ultrafast response of an individual nano-object is also a powerful tool to elucidate the physical mechanisms at the origin of their optical nonlinearities, and their electronic, vibrational and thermal relaxation processes. Experimental investigations of the dynamical response of gold nanorods are shown to be quantitatively modeled in terms of modifications of the metal dielectric function enhanced by plasmonic effects. Ultrafast spectroscopy can also be exploited to unveil hidden physical properties of more complex nanosystems. In this context, two-color femtosecond pump-probe experiments performed on individual

Compact OXC architecture, design and prototype development for flexible waveband routing optical networks.

PubMed

Ishikawa, Tomohiro; Mori, Yojiro; Hasegawa, Hiroshi; Subramaniam, Suresh; Sato, Ken-Ichi; Moriwaki, Osamu

2017-07-10

A novel compact OXC node architecture that combines WSSs and arrays of small scale optical delivery-coupling type switches ("DCSWs") is proposed. Unlike conventional OXC nodes, the WSSs are only responsible for dynamic path bundling ("flexible waveband") while the small scale optical switches route bundled path groups. A network design algorithm that is aware of the routing scheme is also proposed, and numerical experiments elucidate that the necessary number of WSSs and amplifiers can be significantly reduced. A prototype of the proposed OXC is also developed using monolithic arrayed DCSWs. Transmission experiments on the prototype verify the proposal's technical feasibility.

Performance assessment and optimization of an irreversible nano-scale Stirling engine cycle operating with Maxwell-Boltzmann gas

NASA Astrophysics Data System (ADS)

Ahmadi, Mohammad H.; Ahmadi, Mohammad-Ali; Pourfayaz, Fathollah

2015-09-01

Developing new technologies like nano-technology improves the performance of the energy industries. Consequently, emerging new groups of thermal cycles in nano-scale can revolutionize the energy systems' future. This paper presents a thermo-dynamical study of a nano-scale irreversible Stirling engine cycle with the aim of optimizing the performance of the Stirling engine cycle. In the Stirling engine cycle the working fluid is an Ideal Maxwell-Boltzmann gas. Moreover, two different strategies are proposed for a multi-objective optimization issue, and the outcomes of each strategy are evaluated separately. The first strategy is proposed to maximize the ecological coefficient of performance (ECOP), the dimensionless ecological function (ecf) and the dimensionless thermo-economic objective function ( F . Furthermore, the second strategy is suggested to maximize the thermal efficiency ( η), the dimensionless ecological function (ecf) and the dimensionless thermo-economic objective function ( F). All the strategies in the present work are executed via a multi-objective evolutionary algorithms based on NSGA∥ method. Finally, to achieve the final answer in each strategy, three well-known decision makers are executed. Lastly, deviations of the outcomes gained in each strategy and each decision maker are evaluated separately.

Emulsified Zero-Valent Nano-Scale Iron Treatment of Chlorinated Solvent DNAPL Source Areas

DTIC Science & Technology

2010-04-01

The EZVI is composed of food-grade surfactant, biodegradable oil , water, and ZVI particles (either nano- or micro-scale iron), which form...emulsion particles (Figure 2-1). Each emulsion particle or droplet contains ZVI particles in water surrounded by an oil -liquid membrane. Since the...exterior oil membrane of the emulsion droplet has hydrophobic properties similar to that of DNAPL, the droplets are miscible with DNAPL. It is believed

Nano-optical single-photon response mapping of waveguide integrated molybdenum silicide (MoSi) superconducting nanowires.

PubMed

Li, Jian; Kirkwood, Robert A; Baker, Luke J; Bosworth, David; Erotokritou, Kleanthis; Banerjee, Archan; Heath, Robert M; Natarajan, Chandra M; Barber, Zoe H; Sorel, Marc; Hadfield, Robert H

2016-06-27

We present low temperature nano-optical characterization of a silicon-on-insulator (SOI) waveguide integrated SNSPD. The SNSPD is fabricated from an amorphous Mo₈₃Si₁₇ thin film chosen to give excellent substrate conformity. At 350 mK, the SNSPD exhibits a uniform photoresponse under perpendicular illumination, corresponding to a maximum system detection efficiency of approximately 5% at 1550 nm wavelength. Under these conditions 10 Hz dark count rate and 51 ps full width at half maximum (FWHM) timing jitter is observed.

Chip-Scale Architectures for Precise Optical Frequency Synthesis

NASA Astrophysics Data System (ADS)

Yang, Jinghui

Scientists and engineers have investigated various types of stable and accurate optical synthesizers, where mode-locked laser based optical frequency comb synthesizers have been widely investigated. These frequency combs bridge the frequencies from optical domain to microwave domain with orders of magnitude difference, providing a metrological tool for various platforms. The demand for highly robust, scalable, compact and cost-effective femtosecond-laser synthesizers, however, are of great importance for applications in air- or space-borne platforms, where low cost and rugged packaging are particularly required. This has been afforded in the past several years due to breakthroughs in chip-scale nanofabrication, bringing advances in optical frequency combs down to semiconductor chips. These platforms, with significantly enhanced light-matter interaction, provide a fertile sandbox for research rich in nonlinear dynamics, and offer a reliable route towards low-phase noise photonic oscillators, broadband optical frequency synthesizers, miniaturized optical clockwork, and coherent terabit communications. The dissertation explores various types of optical frequency comb synthesizers based on nonlinear microresonators. Firstly, the fundamental mechanism of mode-locking in a high-quality factor microresonator is examined, supported by ultrafast optical characterizations, analytical closed-form solutions and numerical modeling. In the evolution of these frequency microcombs, the key nonlinear dynamical effect governing the comb state coherence is rigorously analyzed. Secondly, a prototype of chip-scale optical frequency synthesizer is demonstrated, with the laser frequency comb stabilized down to instrument-limited 50-mHz RF frequency inaccuracies and 10-16 fractional frequency inaccuracies, near the fundamental limits. Thirdly, a globally stable Turing pattern is achieved and characterized in these nonlinear resonators with high-efficiency conversion, subsequently

Research on optimal path planning algorithm of task-oriented optical remote sensing satellites

NASA Astrophysics Data System (ADS)

Liu, Yunhe; Xu, Shengli; Liu, Fengjing; Yuan, Jingpeng

2015-08-01

GEO task-oriented optical remote sensing satellite, is very suitable for long-term continuous monitoring and quick access to imaging. With the development of high resolution optical payload technology and satellite attitude control technology, GEO optical remote sensing satellites will become an important developing trend for aerospace remote sensing satellite in the near future. In the paper, we focused on GEO optical remote sensing satellite plane array stare imaging characteristics and real-time leading mission of earth observation mode, targeted on satisfying needs of the user with the minimum cost of maneuver, and put forward the optimal path planning algorithm centered on transformation from geographic coordinate space to Field of plane, and finally reduced the burden of the control system. In this algorithm, bounded irregular closed area on the ground would be transformed based on coordinate transformation relations in to the reference plane for field of the satellite payload, and then using the branch and bound method to search for feasible solutions, cutting off the non-feasible solution in the solution space based on pruning strategy; and finally trimming some suboptimal feasible solutions based on the optimization index until a feasible solution for the global optimum. Simulation and visualization presentation software testing results verified the feasibility and effectiveness of the strategy.

Nano Scale Mechanical Analysis of Biomaterials Using Atomic Force Microscopy

NASA Astrophysics Data System (ADS)

Dutta, Diganta

The atomic force microscope (AFM) is a probe-based microscope that uses nanoscale and structural imaging where high resolution is desired. AFM has also been used in mechanical, electrical, and thermal engineering applications. This unique technique provides vital local material properties like the modulus of elasticity, hardness, surface potential, Hamaker constant, and the surface charge density from force versus displacement curve. Therefore, AFM was used to measure both the diameter and mechanical properties of the collagen nanostraws in human costal cartilage. Human costal cartilage forms a bridge between the sternum and bony ribs. The chest wall of some humans is deformed due to defective costal cartilage. However, costal cartilage is less studied compared to load bearing cartilage. Results show that there is a difference between chemical fixation and non-chemical fixation treatments. Our findings imply that the patients' chest wall is mechanically weak and protein deposition is abnormal. This may impact the nanostraws' ability to facilitate fluid flow between the ribs and the sternum. At present, AFM is the only tool for imaging cells' ultra-structure at the nanometer scale because cells are not homogeneous. The first layer of the cell is called the cell membrane, and the layer under it is made of the cytoskeleton. Cancerous cells are different from normal cells in term of cell growth, mechanical properties, and ultra-structure. Here, force is measured with very high sensitivity and this is accomplished with highly sensitive probes such as a nano-probe. We performed experiments to determine ultra-structural differences that emerge when such cancerous cells are subject to treatments such as with drugs and electric pulses. Jurkat cells are cancerous cells. These cells were pulsed at different conditions. Pulsed and non-pulsed Jurkat cell ultra-structures were investigated at the nano meter scale using AFM. Jurkat cell mechanical properties were measured under

Genome-scale modeling of the evolutionary path to C4 photosynthesis

NASA Astrophysics Data System (ADS)

Myers, Christopher R.; Bogart, Eli

In C4 photosynthesis, plants maintain a high carbon dioxide level in specialized bundle sheath cells surrounding leaf veins and restrict CO2 assimilation to those cells, favoring CO2 over O2 in competition for Rubisco active sites. In C3 plants, which do not possess such a carbon concentrating mechanism, CO2 fixation is reduced due to this competition. Despite the complexity of the C4 system, it has evolved convergently from more than 60 independent origins in diverse families of plants around the world over the last 30 million years. We study the evolution of the C4 system in a genome-scale model of plant metabolism that describes interacting mesophyll and bundle sheath cells and enforces key nonlinear kinetic relationships. Adapting the zero-temperature string method for simulating transition paths in physics and chemistry, we find the highest-fitness paths connecting C3 and C4 positions in the model's high-dimensional parameter space, and show that they reproduce known aspects of the C3-C4 transition while making additional predictions about metabolic changes along the path. We explore the relationship between evolutionary history and C4 biochemical subtype, and the effects of atmospheric carbon dioxide levels.

Thermo-activated nano-material for use in optical devices

NASA Astrophysics Data System (ADS)

Mias, Solon; Sudor, Jan; Camon, Henri

2007-05-01

In this paper we describe the use of thermo-activated PNIPAM nano-material in optical switching devices. In other publications, the PNIPAM is used either as a carrier for crystalline colloidal array self-assemblies or as micro-particles that serve as pigment bags. In this publication we use a simpler-to-fabricate pure PNIPAM solution in a semi-dilute regime. The PNIPAM devices produced are transparent at temperatures below a critical temperature of 32°C and become diffusing above this temperature. We show that at 632nm the transmission through the devices is about 75% in the transparent state while the additional attenuation achieved in the diffusing state is of the order of 38 dB. The experimental fall and rise times obtained are large (about 300ms and 5s respectively) due to the non-optimised thermal addressing scheme. In addition, spectral measurements taken in the infrared spectrum (700-1000nm) demonstrate that the cell response is flat over a large portion of the infrared spectrum in both the transparent and the diffusing states.

Meissner effect measurement of single indium particle using a customized on-chip nano-scale superconducting quantum interference device system

NASA Astrophysics Data System (ADS)

Wu, Long; Chen, Lei; Wang, Hao; Liu, Xiaoyu; Wang, Zhen

2017-04-01

As many emergent phenomena of superconductivity appear on a smaller scale and at lower dimension, commercial magnetic property measurement systems (MPMSs) no longer provide the sensitivity necessary to study the Meissner effect of small superconductors. The nano-scale superconducting quantum interference device (nano-SQUID) is considered one of the most sensitive magnetic sensors for the magnetic characterization of mesoscopic or microscopic samples. Here, we develop a customized on-chip nano-SQUID measurement system based on a pulsed current biasing method. The noise performance of our system is approximately 4.6 × 10-17 emu/Hz1/2, representing an improvement of 9 orders of magnitude compared with that of a commercial MPMS (~10-8 emu/Hz1/2). Furthermore, we demonstrate the measurement of the Meissner effect of a single indium (In) particle (of 47 μm in diameter) using our on-chip nano-SQUID system. The system enables the observation of the prompt superconducting transition of the Meissner effect of a single In particle, thereby providing more accurate characterization of the critical field Hc and temperature Tc. In addition, the retrapping field Hre as a function of temperature T of single In particle shows disparate behavior from that of a large ensemble.

The thermal near-field: Coherence, spectroscopy, heat-transfer, and optical forces

NASA Astrophysics Data System (ADS)

Jones, Andrew C.; O'Callahan, Brian T.; Yang, Honghua U.; Raschke, Markus B.

2013-12-01

One of the most universal physical processes shared by all matter at finite temperature is the emission of thermal radiation. The experimental characterization and theoretical description of far-field black-body radiation was a cornerstone in the development of modern physics with the groundbreaking contributions from Gustav Kirchhoff and Max Planck. With its origin in thermally driven fluctuations of the charge carriers, thermal radiation reflects the resonant and non-resonant dielectric properties of media, which is the basis for far-field thermal emission spectroscopy. However, associated with the underlying fluctuating optical source polarization are fundamentally distinct spectral, spatial, resonant, and coherence properties of the evanescent thermal near-field. These properties have been recently predicted theoretically and characterized experimentally for systems with thermally excited molecular, surface plasmon polariton (SPP), and surface phonon polariton (SPhP) resonances. We review, starting with the early historical developments, the emergence of theoretical models, and the description of the thermal near-field based on the fluctuation-dissipation theory and in terms of the electromagnetic local density of states (EM-LDOS). We discuss the optical and spectroscopic characterization of distance dependence, magnitude, spectral distribution, and coherence of evanescent thermal fields. Scattering scanning near-field microscopy proved instrumental as an enabling technique for the investigations of several of these fundamental thermal near-field properties. We then discuss the role of thermal fields in nano-scale heat transfer and optical forces, and the correlation to the van der Waals, Casimir, and Casimir-Polder forces. We conclude with an outlook on the possibility of intrinsic and extrinsic resonant manipulation of optical forces, control of nano-scale radiative heat transfer with optical antennas and metamaterials, and the use of thermal infrared near

Bacterial toxicity comparison between nano- and micro-scaled oxide particles.

PubMed

Jiang, Wei; Mashayekhi, Hamid; Xing, Baoshan

2009-05-01

Toxicity of nano-scaled aluminum, silicon, titanium and zinc oxides to bacteria (Bacillus subtilis, Escherichia coli and Pseudomonas fluorescens) was examined and compared to that of their respective bulk (micro-scaled) counterparts. All nanoparticles but titanium oxide showed higher toxicity (at 20 mg/L) than their bulk counterparts. Toxicity of released metal ions was differentiated from that of the oxide particles. ZnO was the most toxic among the three nanoparticles, causing 100% mortality to the three tested bacteria. Al(2)O(3) nanoparticles had a mortality rate of 57% to B. subtilis, 36% to E. coli, and 70% to P. fluorescens. SiO(2) nanoparticles killed 40% of B. subtilis, 58% of E. coli, and 70% of P. fluorescens. TEM images showed attachment of nanoparticles to the bacteria, suggesting that the toxicity was affected by bacterial attachment. Bacterial responses to nanoparticles were different from their bulk counterparts; hence nanoparticle toxicity mechanisms need to be studied thoroughly.

4-channels coherent perfect absorption (CPA)-type demultiplexer using plasmonic nano spheres

NASA Astrophysics Data System (ADS)

Soltani, Mohamadreza; Keshavarzi, Rasul

2017-10-01

The current research represents a nanoscale and compact 4-channels plasmonic demultiplexer. It includes eight coherent perfect absorption (CPA) - type filters. The operation principle is based on the absorbable formation of a conductive path in the dielectric layer of a plasmonic nano-spheres waveguide. Since the CPA efficiency depends strongly on the number of plasmonic nano-spheres and the nano spheres location, an efficient binary optimization method based on the Particle Swarm Optimization algorithm is used to design an optimized array of the plasmonic nano-sphere in order to achieve the maximum absorption coefficient in the 'off' state.

Small scale adaptive optics experiment systems engineering

NASA Technical Reports Server (NTRS)

Boykin, William H.

1993-01-01

Assessment of the current technology relating to the laser power beaming system which in full scale is called the Beam Transmission Optical System (BTOS). Evaluation of system integration efforts are being conducted by the various government agencies and industry. Concepts are being developed for prototypes of adaptive optics for a BTOS.

A nano-scale mirror-like surface of Ti-6Al-4V attained by chemical mechanical polishing

NASA Astrophysics Data System (ADS)

Chenliang, Liang; Weili, Liu; Shasha, Li; Hui, Kong; Zefang, Zhang; Zhitang, Song

2016-05-01

Metal Ti and its alloys have been widely utilized in the fields of aviation, medical science, and micro-electro-mechanical systems, for its excellent specific strength, resistance to corrosion, and biological compatibility. As the application of Ti moves to the micro or nano scale, however, traditional methods of planarization have shown their short slabs. Thus, we introduce the method of chemical mechanical polishing (CMP) to provide a new way for the nano-scale planarization method of Ti alloys. We obtain a mirror-like surface, whose flatness is of nano-scale, via the CMP method. We test the basic mechanical behavior of Ti-6Al-4V (Ti64) in the CMP process, and optimize the composition of CMP slurry. Furthermore, the possible reactions that may take place in the CMP process have been studied by electrochemical methods combined with x-ray photoelectron spectroscopy (XPS). An equivalent circuit has been built to interpret the dynamic of oxidation. Finally, a model has been established to explain the synergy of chemical and mechanical effects in the CMP of Ti-6Al-4V. Project supported by the National Major Scientific and Technological Special Project during the Twelfth Five-year Plan Period of China (Grant No. 2009ZX02030-1), the National Natural Science Foundation of China (Grant No. 51205387), the Support by Science and Technology Commission of Shanghai City, China (Grant No. 11nm0500300), and the Science and Technology Commission of Shanghai City, China (Grant No. 14XD1425300).

Stable isomers and electronic, vibrational, and optical properties of WS2 nano-clusters: A first-principles study

NASA Astrophysics Data System (ADS)

Hafizi, Roohollah; Hashemifar, S. Javad; Alaei, Mojtaba; Jangrouei, MohammadReza; Akbarzadeh, Hadi

2016-12-01

In this paper, we employ an evolutionary algorithm along with the full-potential density functional theory (DFT) computations to perform a comprehensive search for the stable structures of stoichiometric (WS2)n nano-clusters (n = 1 - 9), within three different exchange-correlation functionals. Our results suggest that n = 5 and 8 are possible candidates for the low temperature magic sizes of WS2 nano-clusters while at temperatures above 500 Kelvin, n = 7 exhibits a comparable relative stability with n = 8. The electronic properties and energy gap of the lowest energy isomers were computed within several schemes, including semilocal Perdew-Burke-Ernzerhof and Becke-Lee-Yang-Parr functionals, hybrid B3LYP functional, many body based DFT+GW approach, ΔSCF method, and time dependent DFT calculations. Vibrational spectra of the lowest lying isomers, computed by the force constant method, are used to address IR spectra and thermal free energy of the clusters. Time dependent density functional calculation in a real time domain is applied to determine the full absorption spectra and optical gap of the lowest energy isomers of the WS2 nano-clusters.

Droplets and the three-phase contact line at the nano-scale. Statics and dynamics

NASA Astrophysics Data System (ADS)

Yatsyshin, Petr; Sibley, David; Savva, Nikos; Kalliadasis, Serafim

2014-11-01

Understanding the behaviour of the solid-liquid-vapour contact line at the scale of several tens of molecular diameters is important in wetting hydrodynamics with applications in micro- and nano-fluidics, including the design of lab-on-a-chip devices and surfaces with specific wetting properties. Due to the fluid inhomogeneity at the nano-scale, the application of continuum-mechanical approaches is limited, and a natural way to remedy this is to seek descriptions accounting for the non-local molecular-level interactions. Density Functional Theory (DFT) for fluids offers a statistical-mechanical framework based on expressing the free energy of the fluid-solid pair as a functional of the spatially varying fluid density. DFT allows us to investigate small drops deposited on planar substrates whilst keeping track of the microscopic structural details of the fluid. Starting from a model of intermolecular forces, we systematically obtain interfaces, surface tensions, and the microscopic contact angle. Using a dynamic extension of equilibrium DFT, we investigate the diffusion-driven evolution of the three-phase contact line to gain insight into the dynamic behaviour of the microscopic contact angle, which is still under debate.

Quantum properties of light emitted by dipole nano-laser

NASA Astrophysics Data System (ADS)

Ghannam, Talal

Recent technological advances allow entire optical systems to be lithographically implanted on small silicon chips. These systems include tiny semiconductor lasers that function as light sources for digital optical signals. Future advances will rely on even smaller components. At the theoretical limit of this process, the smallest lasers will have an active medium consisting of a single atom (natural or artificial). Several suggestions for how this can be accomplished have already been published, such as nano-lasers based on photonic crystals and nano wires. In particular, the "dipole nanolaser" consists of a single quantum dot functioning as the active medium. It is optically coupled to a metal nanoparticles that form a resonant cavity. Laser light is generated from the near-field optical signal. The proposed work is a theoretical exploration of the nature of the resulting laser light. The dynamics of the system will be studied and relevant time scales described. These will form the basis for a set of operator equations describing the quantum properties of the emitted light. The dynamics will be studied in both density matrix and quantum Langevin formulations, with attention directed to noise sources. The equations will be linearized and solved using standard techniques. The result of the study will be a set of predicted noise spectra describing the statistics of the emitted light. The goal will be to identify the major noise contributions and suggest methods for suppressing them. This will be done by studying the probability of getting squeezed light from the nanoparticle for the certain scheme of parameters.

Nano-graphene in biomedicine: theranostic applications.

PubMed

Yang, Kai; Feng, Liangzhu; Shi, Xiaoze; Liu, Zhuang

2013-01-21

Owing to their unique physical and chemical properties, graphene and its derivatives such as graphene oxide (GO), reduced graphene oxide (RGO) and GO-nanocomposites have attracted tremendous interest in many different fields including biomedicine in recent years. With every atom exposed on its surface, single-layered graphene shows ultra-high surface area available for efficient molecular loading and bioconjugation, and has been widely explored as novel nano-carriers for drug and gene delivery. Utilizing the intrinsic near-infrared (NIR) optical absorbance, in vivo graphene-based photothermal therapy has been realized, achieving excellent anti-tumor therapeutic efficacy in animal experiments. A variety of inorganic nanoparticles can be grown on the surface of nano-graphene, obtaining functional graphene-based nanocomposites with interesting optical and magnetic properties useful for multi-modal imaging and imaging-guided cancer therapy. Moreover, significant efforts have also been devoted to study the behaviors and toxicology of functionalized nano-graphene in animals. It has been uncovered that both surface chemistry and sizes play key roles in controlling the biodistribution, excretion, and toxicity of nano-graphene. Biocompatibly coated nano-graphene with ultra-small sizes can be cleared out from body after systemic administration, without rendering noticeable toxicity to the treated mice. In this review article, we will summarize the latest progress in this rapidly growing field, and discuss future prospects and challenges of using graphene-based materials for theranostic applications.

In Vitro Phototoxicity and Hazard Identification of Nano-scale Titanium Dioxide

EPA Science Inventory

Nano-titanium dioxide (nano-Ti02) catalyzes many reactions under UV radiation and is hypothesized to cause phototoxicity. A human-derived line of retinal pigment epithelial cells (ARPE-19) was treated with six different samples of nano-Ti02 and exposed to UVA radiation. The Ti02 ...

A common-path optical coherence tomography based electrode for structural imaging of nerves and recording of action potentials

NASA Astrophysics Data System (ADS)

Islam, M. Shahidul; Haque, Md. Rezuanul; Oh, Christian M.; Wang, Yan; Park, B. Hyle

2013-03-01

Current technologies for monitoring neural activity either use different variety of electrodes (electrical recording) or require contrast agents introduced exogenously or through genetic modification (optical imaging). Here we demonstrate an optical method for non-contact and contrast agent free detection of nerve activity using phase-resolved optical coherence tomography (pr-OCT). A common-path variation of the pr-OCT is recently implemented and the developed system demonstrated the capability to detect rapid transient structural changes that accompany neural spike propagation. No averaging over multiple trials was required, indicating its capability of single-shot detection of individual impulses from functionally stimulated Limulus optic nerve. The strength of this OCT-based optical electrode is that it is a contactless method and does not require any exogenous contrast agent. With further improvements in accuracy and sensitivity, this optical electrode will play a complementary role to the existing recording technologies in future.

The Influence of Fluorination on Nano-Scale Phase Separation and Photovoltaic Performance of Small Molecular/PC71BM Blends

PubMed Central

Lu, Zhen; Liu, Wen; Li, Jingjing; Fang, Tao; Li, Wanning; Zhang, Jicheng; Feng, Feng; Li, Wenhua

2016-01-01

To investigate the fluorination influence on the photovoltaic performance of small molecular based organic solar cells (OSCs), six small molecules based on 2,1,3-benzothiadiazole (BT), and diketopyrrolopyrrole (DPP) as core and fluorinated phenyl (DFP) and triphenyl amine (TPA) as different terminal units (DFP-BT-DFP, DFP-BT-TPA, TPA-BT-TPA, DFP-DPP-DFP, DFP-DPP-TPA, and TPA-DPP-TPA) were synthesized. With one or two fluorinated phenyl as the end group(s), HOMO level of BT and DPP based small molecular donors were gradually decreased, inducing high open circuit voltage for fluorinated phenyl based OSCs. DFP-BT-TPA and DFP-DPP-TPA based blend films both displayed stronger nano-scale aggregation in comparison to TPA-BT-TPA and TPA-DPP-TPA, respectively, which would also lead to higher hole motilities in devices. Ultimately, improved power conversion efficiency (PCE) of 2.17% and 1.22% was acquired for DFP-BT-TPA and DFP-DPP-TPA based devices, respectively. These results demonstrated that the nano-scale aggregation size of small molecules in photovoltaic devices could be significantly enhanced by introducing a fluorine atom at the donor unit of small molecules, which will provide understanding about the relationship of chemical structure and nano-scale phase separation in OSCs. PMID:28335208

Vibrational Analysis of a Shipboard Free Electron Laser Beam Path

DTIC Science & Technology

2011-12-01

2 Figure 2. Optical Extraction (η) vs. Separation and Electron Beam Tilt for a Notional FEL Oscillator . (From [1...in Figure 2. Figure 2. Optical Extraction (η) vs. Separation and Electron Beam Tilt for a Notional FEL Oscillator . (From [1]) The narrow beam...3 is a top down view of the entire electron beam path. Figure 3. Electron Beam Line of a Notional FEL Oscillator . 2. Optical Path The optical

Developing an Effective Model for Shale Gas Flow in Nano-scale Pore Clusters based on FIB-SEM Images

NASA Astrophysics Data System (ADS)

Jiang, W. B.; Lin, M.; Yi, Z. X.; Li, H. S.

2016-12-01

Nano-scale pores existed in the form of clusters are the controlling void space in shale gas reservoir. Gas transport in nanopores which has a significant influence on shale gas' recoverability displays multiple transport regimes, including viscous, slippage flow and Knudsen diffusion. In addition, it is also influenced by pore space characteristics. For convenience and efficiency consideration, it is necessary to develop an upscaling model from nano pore to pore cluster scale. Existing models are more like framework functions that provide a format, because the parameters that represent pore space characteristics are underdetermined and may have multiple possibilities. Therefore, it is urgent to make them clear and obtained a model that is closer to reality. FIB-SEM imaging technology is able to acquire three dimensional images with nanometer resolution that nano pores can be visible. Based on the images of two shale samples, we used a high-precision pore network extraction algorithm to generate equivalent pore networks and simulate multiple regime (non-Darcy) flow in it. Several structural parameters can be obtained through pore network modelling. It is found that although the throat-radius distributions are very close, throat flux-radius distributions of different samples can be divided into two categories. The variation of tortuosity with pressure and the overall trend of throat-flux distribution changes with pressure are disclosed. A deeper understanding of shale gas flow in nano-scale pore clusters is obtained. After all, an upscaling model that connects absolute permeability, apparent permeability and other characteristic parameters is proposed, and the best parameter scheme considering throat number-radius distribution and flowing porosity for this model is selected out of three schemes based on pore scale results, and it can avoid multiple-solution problem and is useful in reservoir modelling and experiment result analysis, etc. This work is supported by

Structural and optical characterization of GaAs nano-crystals selectively grown on Si nano-tips by MOVPE.

PubMed

Skibitzki, Oliver; Prieto, Ivan; Kozak, Roksolana; Capellini, Giovanni; Zaumseil, Peter; Arroyo Rojas Dasilva, Yadira; Rossell, Marta D; Erni, Rolf; von Känel, Hans; Schroeder, Thomas

2017-03-01

We present the nanoheteroepitaxial growth of gallium arsenide (GaAs) on nano-patterned silicon (Si) (001) substrates fabricated using a CMOS technology compatible process. The selective growth of GaAs nano-crystals (NCs) was achieved at 570 °C by MOVPE. A detailed structure and defect characterization study of the grown nano-heterostructures was performed using scanning transmission electron microscopy, x-ray diffraction, micro-Raman, and micro-photoluminescence (μ-PL) spectroscopy. The results show single-crystalline, nearly relaxed GaAs NCs on top of slightly, by the SiO 2 -mask compressively strained Si nano-tips (NTs). Given the limited contact area, GaAs/Si nanostructures benefit from limited intermixing in contrast to planar GaAs films on Si. Even though a few growth defects (e.g. stacking faults, micro/nano-twins, etc) especially located at the GaAs/Si interface region were detected, the nanoheterostructures show intensive light emission, as investigated by μ-PL spectroscopy. Achieving well-ordered high quality GaAs NCs on Si NTs may provide opportunities for superior electronic, photonic, or photovoltaic device performances integrated on the silicon technology platform.

Tight real-time synchronization of a microwave clock to an optical clock across a turbulent air path

PubMed Central

Bergeron, Hugo; Sinclair, Laura C.; Swann, William C.; Nelson, Craig W.; Deschênes, Jean-Daniel; Baumann, Esther; Giorgetta, Fabrizio R.; Coddington, Ian; Newbury, Nathan R.

2018-01-01

The ability to distribute the precise time and frequency from an optical clock to remote platforms could enable future precise navigation and sensing systems. Here we demonstrate tight, real-time synchronization of a remote microwave clock to a master optical clock over a turbulent 4-km open air path via optical two-way time-frequency transfer. Once synchronized, the 10-GHz frequency signals generated at each site agree to 10−14 at one second and below 10−17 at 1000 seconds. In addition, the two clock times are synchronized to ±13 fs over an 8-hour period. The ability to phase-synchronize 10-GHz signals across platforms supports future distributed coherent sensing, while the ability to time-synchronize multiple microwave-based clocks to a high-performance master optical clock supports future precision navigation/timing systems. PMID:29607352

Tight real-time synchronization of a microwave clock to an optical clock across a turbulent air path.

PubMed

Bergeron, Hugo; Sinclair, Laura C; Swann, William C; Nelson, Craig W; Deschênes, Jean-Daniel; Baumann, Esther; Giorgetta, Fabrizio R; Coddington, Ian; Newbury, Nathan R

2016-04-01

The ability to distribute the precise time and frequency from an optical clock to remote platforms could enable future precise navigation and sensing systems. Here we demonstrate tight, real-time synchronization of a remote microwave clock to a master optical clock over a turbulent 4-km open air path via optical two-way time-frequency transfer. Once synchronized, the 10-GHz frequency signals generated at each site agree to 10 -14 at one second and below 10 -17 at 1000 seconds. In addition, the two clock times are synchronized to ±13 fs over an 8-hour period. The ability to phase-synchronize 10-GHz signals across platforms supports future distributed coherent sensing, while the ability to time-synchronize multiple microwave-based clocks to a high-performance master optical clock supports future precision navigation/timing systems.

Temporal scaling of the growth dependent optical properties of microalgae

NASA Astrophysics Data System (ADS)

Zhao, J. M.; Ma, C. Y.; Liu, L. H.

2018-07-01

The optical properties of microalgae are basic parameters for analyzing light field distribution in photobioreactors (PBRs). With the growth of microalgae cell, their optical properties will vary with growth time due to accumulation of pigment and lipid, cell division and metabolism. In this work, we report a temporal scaling behavior of the growth dependent optical properties of microalgae cell suspensions with both experimental and theoretical evidence presented. A new concept, the temporal scaling function (TSF), defined as the ratio of absorption or scattering cross-sections at growth phase to that at stationary phase, is introduced to characterize the temporal scaling behavior. The temporal evolution and temporal scaling characteristics of the absorption and scattering cross-sections of three example microalgae species, Chlorella vulgaris, Chlorella pyrenoidosa, and Chlorella protothecoides, were experimentally studied at spectral range 380-850 nm. It is shown that the TSFs of the absorption and scattering cross-sections for different microalgae species are approximately constant at different wavelength, which confirms theoretical predictions very well. With the aid of the temporal scaling relation, the optical properties at any growth time can be calculated based on those measured at stationary phase, hence opens a new way to determine the time-dependent optical properties of microalgae. The findings of this work will help the understanding of time dependent optical properties of microalgae and facilitate their applications in light field analysis in PBRs design.

Enhancement of magnetoresistance by hydrogen ion treatment for current-perpendicular-to-plane giant magnetoresistive films with a current-confined-path nano-oxide layer

NASA Astrophysics Data System (ADS)

Yuasa, H.; Hara, M.; Murakami, S.; Fuji, Y.; Fukuzawa, H.; Zhang, K.; Li, M.; Schreck, E.; Wang, P.; Chen, M.

2010-09-01

We have enhanced magnetoresistance (MR) for current-perpendicular-to-plane giant-magnetoresistive (CPP-GMR) films with a current-confined-path nano-oxide layer (CCP-NOL). In order to realize higher purity in Cu for CCPs, hydrogen ion treatment (HIT) was applied as the CuOx reduction process. By applying the HIT process, an MR ratio was increased to 27.4% even in the case of using conventional FeCo magnetic layer, from 13.0% for a reference without the HIT process. Atom probe tomography data confirmed oxygen reduction by the HIT process in the CCP-NOL. The relationship between oxygen counts and MR ratio indicates that further oxygen reduction would realize an MR ratio greater than 50%.

Optical pumping in a whispering-mode optical waveguide

DOEpatents

Kurnit, N.A.

1981-08-11

A device and method for optical pumping in a whispering mode optical waveguide are described. Both a helical ribbon and cylinder are disclosed which incorporate an additional curvature for confining the beam to increase intensity. An optical pumping medium is disposed in the optical path of the beam as it propagates along the waveguide. Optical pumping is enhanced by the high intensities of the beam and long interaction path lengths which are achieved in a small volume.

Wafer-scale plasmonic and photonic crystal sensors

NASA Astrophysics Data System (ADS)

George, M. C.; Liu, J.-N.; Farhang, A.; Williamson, B.; Black, M.; Wangensteen, T.; Fraser, J.; Petrova, R.; Cunningham, B. T.

2015-08-01

200 mm diameter wafer-scale fabrication, metrology, and optical modeling results are reviewed for surface plasmon resonance (SPR) sensors based on 2-D metallic nano-dome and nano-hole arrays (NHA's) as well as 1-D photonic crystal sensors based on a leaky-waveguide mode resonance effect, with potential applications in label free sensing, surface enhanced Raman spectroscopy (SERS), and surface-enhanced fluorescence spectroscopy (SEFS). Potential markets include micro-arrays for medical diagnostics, forensic testing, environmental monitoring, and food safety. 1-D and 2-D nanostructures were fabricated on glass, fused silica, and silicon wafers using optical lithography and semiconductor processing techniques. Wafer-scale optical metrology results are compared to FDTD modeling and presented along with application-based performance results, including label-free plasmonic and photonic crystal sensing of both surface binding kinetics and bulk refractive index changes. In addition, SEFS and SERS results are presented for 1-D photonic crystal and 2-D metallic nano-array structures. Normal incidence transmittance results for a 550 nm pitch NHA showed good bulk refractive index sensitivity, however an intensity-based design with 665 nm pitch was chosen for use as a compact, label-free sensor at both 650 and 632.8 nm wavelengths. The optimized NHA sensor gives an SPR shift of about 480 nm per refractive index unit when detecting a series of 0-40% glucose solutions, but according to modeling shows about 10 times greater surface sensitivity when operating at 532 nm. Narrow-band photonic crystal resonance sensors showed quality factors over 200, with reasonable wafer-uniformity in terms of both resonance position and peak height.

Multilayered metal-insulator nanocavities: toward tunable multi-resonance nano-devices for integrated optics

NASA Astrophysics Data System (ADS)

Song, Junyeob; Zhou, Wei

2017-02-01

Plasmonic nanocavities can control light flows and enhance light-mater interactions at subwavelength scale, and thus can potentially be used as nanoscale components in integrated optics systems either for passive optical coupling, or for active optical modulation and emission. In this work, we investigated a new type of multilayered metal-insulator optical nanocavities that can support multiple localized plasmon resonances with ultra-small mode volumes. The total number of resonance peaks and their resonance wavelengths can be freely and accurately controlled by simple geometric design rules. Multi-resonance plasmonic nanocavities can serve as a nanoscale wavelength-multiplexed optical components in integrated optics systems, such as optical couplers, light emitters, nanolasers, optical sensors, and optical modulators.

Motion Control and Optical Interrogation of a Levitating Single Nitrogen Vacancy in Vacuum.

PubMed

Conangla, Gerard P; Schell, Andreas W; Rica, Raúl A; Quidant, Romain

2018-05-24

Levitation optomechanics exploits the unique mechanical properties of trapped nano-objects in vacuum to address some of the limitations of clamped nanomechanical resonators. In particular, its performance is foreseen to contribute to a better understanding of quantum decoherence at the mesoscopic scale as well as to lead to novel ultrasensitive sensing schemes. While most efforts have focused so far on the optical trapping of low-absorption silica particles, further opportunities arise from levitating objects with internal degrees of freedom, such as color centers. Nevertheless, inefficient heat dissipation at low pressures poses a challenge because most nano-objects, even with low-absorption materials, experience photodamage in an optical trap. Here, by using a Paul trap, we demonstrate levitation in vacuum and center-of-mass feedback cooling of a nanodiamond hosting a single nitrogen-vacancy center. The achieved level of motion control enables us to optically interrogate and characterize the emitter response. The developed platform is applicable to a wide range of other nano-objects and represents a promising step toward coupling internal and external degrees of freedom.

Nano Mechanical Machining Using AFM Probe

NASA Astrophysics Data System (ADS)

Mostofa, Md. Golam

Complex miniaturized components with high form accuracy will play key roles in the future development of many products, as they provide portability, disposability, lower material consumption in production, low power consumption during operation, lower sample requirements for testing, and higher heat transfer due to their very high surface-to-volume ratio. Given the high market demand for such micro and nano featured components, different manufacturing methods have been developed for their fabrication. Some of the common technologies in micro/nano fabrication are photolithography, electron beam lithography, X-ray lithography and other semiconductor processing techniques. Although these methods are capable of fabricating micro/nano structures with a resolution of less than a few nanometers, some of the shortcomings associated with these methods, such as high production costs for customized products, limited material choices, necessitate the development of other fabricating techniques. Micro/nano mechanical machining, such an atomic force microscope (AFM) probe based nano fabrication, has, therefore, been used to overcome some the major restrictions of the traditional processes. This technique removes material from the workpiece by engaging micro/nano size cutting tool (i.e. AFM probe) and is applicable on a wider range of materials compared to the photolithographic process. In spite of the unique benefits of nano mechanical machining, there are also some challenges with this technique, since the scale is reduced, such as size effects, burr formations, chip adhesions, fragility of tools and tool wear. Moreover, AFM based machining does not have any rotational movement, which makes fabrication of 3D features more difficult. Thus, vibration-assisted machining is introduced into AFM probe based nano mechanical machining to overcome the limitations associated with the conventional AFM probe based scratching method. Vibration-assisted machining reduced the cutting forces

Enhanced optical-to-THz conversion efficiency of photoconductive antenna using dielectric nano-layer encapsulation

NASA Astrophysics Data System (ADS)

Gupta, Abhishek; Rana, Goutam; Bhattacharya, Arkabrata; Singh, Abhishek; Jain, Ravikumar; Bapat, Rudheer D.; Duttagupta, S. P.; Prabhu, S. S.

2018-05-01

Photoconductive antennas (PCAs) are among the most conventional devices used for emission as well as detection of terahertz (THz) radiation. However, due to their low optical-to-THz conversion efficiencies, applications of these devices in out-of-laboratory conditions are limited. In this paper, we report several factors of enhancement in THz emission efficiency from conventional PCAs by coating a nano-layer of dielectric (TiO2) on the active area between the electrodes of a semi-insulating GaAs-based device. Extensive experiments were done to show the effect of thicknesses of the TiO2 layer on the THz power enhancement with different applied optical power and bias voltages. Multiphysics simulations were performed to elucidate the underlying physics behind the enhancement of efficiency of the PCA. Additionally, this layer increases the robustness of the electrode gaps of the PCAs with high electrical insulation as well as protect it from external dust particles.

Chip-scale integrated optical interconnects: a key enabler for future high-performance computing

NASA Astrophysics Data System (ADS)

Haney, Michael; Nair, Rohit; Gu, Tian

2012-01-01

High Performance Computing (HPC) systems are putting ever-increasing demands on the throughput efficiency of their interconnection fabrics. In this paper, the limits of conventional metal trace-based inter-chip interconnect fabrics are examined in the context of state-of-the-art HPC systems, which currently operate near the 1 GFLOPS/W level. The analysis suggests that conventional metal trace interconnects will limit performance to approximately 6 GFLOPS/W in larger HPC systems that require many computer chips to be interconnected in parallel processing architectures. As the HPC communications bottlenecks push closer to the processing chips, integrated Optical Interconnect (OI) technology may provide the ultra-high bandwidths needed at the inter- and intra-chip levels. With inter-chip photonic link energies projected to be less than 1 pJ/bit, integrated OI is projected to enable HPC architecture scaling to the 50 GFLOPS/W level and beyond - providing a path to Peta-FLOPS-level HPC within a single rack, and potentially even Exa-FLOPSlevel HPC for large systems. A new hybrid integrated chip-scale OI approach is described and evaluated. The concept integrates a high-density polymer waveguide fabric directly on top of a multiple quantum well (MQW) modulator array that is area-bonded to the Silicon computing chip. Grayscale lithography is used to fabricate 5 μm x 5 μm polymer waveguides and associated novel small-footprint total internal reflection-based vertical input/output couplers directly onto a layer containing an array of GaAs MQW devices configured to be either absorption modulators or photodetectors. An external continuous wave optical "power supply" is coupled into the waveguide links. Contrast ratios were measured using a test rider chip in place of a Silicon processing chip. The results suggest that sub-pJ/b chip-scale communication is achievable with this concept. When integrated into high-density integrated optical interconnect fabrics, it could provide

Bending the Curve: Sensitivity to Bending of Curved Paths and Application in Room-Scale VR.

PubMed

Langbehn, Eike; Lubos, Paul; Bruder, Gerd; Steinicke, Frank

2017-04-01

Redirected walking (RDW) promises to allow near-natural walking in an infinitely large virtual environment (VE) by subtle manipulations of the virtual camera. Previous experiments analyzed the human sensitivity to RDW manipulations by focusing on the worst-case scenario, in which users walk perfectly straight ahead in the VE, whereas they are redirected on a circular path in the real world. The results showed that a physical radius of at least 22 meters is required for undetectable RDW. However, users do not always walk exactly straight in a VE. So far, it has not been investigated how much a physical path can be bent in situations in which users walk a virtual curved path instead of a straight one. Such curved walking paths can be often observed, for example, when users walk on virtual trails, through bent corridors, or when circling around obstacles. In such situations the question is not, whether or not the physical path can be bent, but how much the bending of the physical path may vary from the bending of the virtual path. In this article, we analyze this question and present redirection by means of bending gains that describe the discrepancy between the bending of curved paths in the real and virtual environment. Furthermore, we report the psychophysical experiments in which we analyzed the human sensitivity to these gains. The results reveal encouragingly wider detection thresholds than for straightforward walking. Based on our findings, we discuss the potential of curved walking and present a first approach to leverage bent paths in a way that can provide undetectable RDW manipulations even in room-scale VR.

Toward giga-pixel nanoscopy on a chip: a computational wide-field look at the nano-scale without the use of lenses

PubMed Central

McLeod, Euan; Luo, Wei; Mudanyali, Onur; Greenbaum, Alon

2013-01-01

The development of lensfree on-chip microscopy in the past decade has opened up various new possibilities for biomedical imaging across ultra-large fields of view using compact, portable, and cost-effective devices. However, until recently, its ability to resolve fine features and detect ultra-small particles has not rivalled the capabilities of the more expensive and bulky laboratory-grade optical microscopes. In this Frontier Review, we highlight the developments over the last two years that have enabled computational lensfree holographic on-chip microscopy to compete with and, in some cases, surpass conventional bright-field microscopy in its ability to image nano-scale objects across large fields of view, yielding giga-pixel phase and amplitude images. Lensfree microscopy has now achieved a numerical aperture as high as 0.92, with a spatial resolution as small as 225 nm across a large field of view e.g., >20 mm2. Furthermore, the combination of lensfree microscopy with self-assembled nanolenses, forming nano-catenoid minimal surfaces around individual nanoparticles has boosted the image contrast to levels high enough to permit bright-field imaging of individual particles smaller than 100 nm. These capabilities support a number of new applications, including, for example, the detection and sizing of individual virus particles using field-portable computational on-chip microscopes. PMID:23592185

Nano-cone optical fiber array sensors for MiRNA profiling

NASA Astrophysics Data System (ADS)

Wang, Yunshan; Senapati, Satyajyoti; Stoddart, Paul; Howard, Scott; Chang, Hsueh-Chia

2013-09-01

Up/down regulation of microRNA panels has been correlated to cardiovascular diseases and cancer. Frequent miRNA profiling at home can hence allow early cancer diagnosis and home-use chronic disease monitoring, thus reducing both mortality rate and healthcare cost. However, lifetime of miRNAs is less than 1 hour without preservation and their concentrations range from pM to mM. Despite rapid progress in the last decade, modern nucleic acid analysis methods still do not allow personalized miRNA profiling---Real-time PCR and DNA micro-array both require elaborate miRNA preservation steps and expensive equipment and nano pore sensors cannot selectively quantify a large panel with a large dynamic range. We report a novel and low-cost optical fiber sensing platform, which has the potential to profile a panel of miRNA with simple LED light sources and detectors. The individual tips of an optical imaging fiber bundle (mm in diameter with 7000 fiber cores) were etched into cones with 10 nm radius of curvature and coated with Au. FRET (Forster Resonant Energy Transfer) hairpin oligo probes, with the loop complementary to a specific miRNA that can release the hairpin, were functionalized onto the conic tips. Exciting light in the optical fiber waveguide is optimally coupled to surface plasmonics on the gold surface, which then converges to the conic tips with two orders of magnitude enhancement in intensity. Unlike nanoparticle plasmonics, tip plasmonics can be excited over a large band width and hence the plasmonic enhanced fluorescence signal of the FRET reporter is also focused towards the tip--- and is further enhanced with the periodic resonant grid of the fiber array which gives rise to pronounced standing wave interference patterns. Multiplexing is realized by functionalizing different probes onto one fiber bundle using a photoactivation process.

Efficient use of strong light for high photosynthetic productivity: interrelationships between the optical path, the optimal population density and cell-growth inhibition.

PubMed

Richmond, Amos; Cheng-Wu, Zhang; Zarmi, Yair

2003-07-01

The interrelationships between the optical path in flat plate reactors and photosynthetic productivity were elucidated. In preliminary works, a great surge in photosynthetic productivity was attained in flat plate photoreactors with an ultra short (e.g. 1.0 cm) optical path, in which extremely high culture density was facilitated by vigorous stirring and strong light. This surge in net photosynthetic efficiency was associated with a very significant increase in the optimal population density facilitated by the very short optical path (OP). A salient feature of these findings concerns the necessity to address growth inhibition (GI) which becomes increasingly manifested as cell concentration rises above a certain, species-specific, threshold (e.g. 1-2 billion cells of Nannochloropsis sp. ml(-1)). Indeed, ultrahigh cell density cultures may be established and sustained only if growth inhibition is continuously, or at least frequently, removed. Nannochloropsis culture from which GI was not removed, yielded 60 mg(-1) h(-1), yielding 260 mg l(-1) h(-1) when GI was removed. Two basic factors crucial for obtaining maximal photosynthetic productivity and efficiency in strong photon irradiance are defined: (1) areal cell density must be optimal, as high as possible (cell growth inhibition having been eliminated), insuring the average photon irradiance (I(av)) available per cell is falling at the end of the linear phase of the PI(av) curve, relating rate of photosynthesis to I(av), i.e. approximately photon irradiance per cell. (2) The light-dark (L-D) cycle period, which is determined by travel time of cells between the dark and the light volumes along the optical path, should be made as short as practically feasible, so as to approach, as much as possible the photosynthetic unit turnover time. This is obtainable in flat plate reactors by reducing the OP to as small a magnitude as is practically feasible.

Plasmonic optical nanotweezers

NASA Astrophysics Data System (ADS)

Kotb, Rehab; El Maklizi, Mahmoud; Ismail, Yehea; Swillam, Mohamed A.

2017-02-01

Plasmonic grating structures can be used in many applications such as nanolithography and optical trapping. In this paper, we used plasmonic grating as optical tweezers to trap and manipulate dielectric nano-particles. Different plasmonic grating structures with single, double, and triple slits have been investigated and analyzed. The three configurations are optimized and compared to find the best candidate to trap and manipulate nanoparticles. The three optimized structures results in capability to super focusing and beaming the light effectively beyond the diffraction limit. A high transverse gradient optical force is obtained using the triple slit configuration that managed to significantly enhance the field and its gradient. Therefore, it has been chosen as an efficient optical tweezers. This structure managed to trap sub10nm particles efficiently. The resultant 50KT potential well traps the nano particles stably. The proposed structure is used also to manipulate the nano-particles by simply changing the angle of the incident light. We managed to control the movement of nano particle over an area of (5μm x 5μm) precisely. The proposed structure has the advantage of trapping and manipulating the particles outside the structure (not inside the structure such as the most proposed optical tweezers). As a result, it can be used in many applications such as drug delivery and biomedical analysis.

Nano ZnO embedded in Chitosan matrix for vibration sensor application

NASA Astrophysics Data System (ADS)

Praveen, E.; Murugan, S.; Jayakumar, K.

2015-06-01

Biopolymer Chitosan is embedded with various concentration of ZnO nano particle and such a bio-nano composite electret has been fabricated by casting method. The morphological, structural, optical and electrical characterization of the bio-nano composite electret film have been carried out. Isolation and piezoelectric measurements of bio-nano composite have also been carried out indicating the possibility of using it as a mechanical sensor element.

Non-linear, non-monotonic effect of nano-scale roughness on particle deposition in absence of an energy barrier: Experiments and modeling

PubMed Central

Jin, Chao; Glawdel, Tomasz; Ren, Carolyn L.; Emelko, Monica B.

2015-01-01

Deposition of colloidal- and nano-scale particles on surfaces is critical to numerous natural and engineered environmental, health, and industrial applications ranging from drinking water treatment to semi-conductor manufacturing. Nano-scale surface roughness-induced hydrodynamic impacts on particle deposition were evaluated in the absence of an energy barrier to deposition in a parallel plate system. A non-linear, non-monotonic relationship between deposition surface roughness and particle deposition flux was observed and a critical roughness size associated with minimum deposition flux or “sag effect” was identified. This effect was more significant for nanoparticles (<1 μm) than for colloids and was numerically simulated using a Convective-Diffusion model and experimentally validated. Inclusion of flow field and hydrodynamic retardation effects explained particle deposition profiles better than when only the Derjaguin-Landau-Verwey-Overbeek (DLVO) force was considered. This work provides 1) a first comprehensive framework for describing the hydrodynamic impacts of nano-scale surface roughness on particle deposition by unifying hydrodynamic forces (using the most current approaches for describing flow field profiles and hydrodynamic retardation effects) with appropriately modified expressions for DLVO interaction energies, and gravity forces in one model and 2) a foundation for further describing the impacts of more complicated scales of deposition surface roughness on particle deposition. PMID:26658159

Non-linear, non-monotonic effect of nano-scale roughness on particle deposition in absence of an energy barrier: Experiments and modeling

NASA Astrophysics Data System (ADS)

Jin, Chao; Glawdel, Tomasz; Ren, Carolyn L.; Emelko, Monica B.

2015-12-01

Deposition of colloidal- and nano-scale particles on surfaces is critical to numerous natural and engineered environmental, health, and industrial applications ranging from drinking water treatment to semi-conductor manufacturing. Nano-scale surface roughness-induced hydrodynamic impacts on particle deposition were evaluated in the absence of an energy barrier to deposition in a parallel plate system. A non-linear, non-monotonic relationship between deposition surface roughness and particle deposition flux was observed and a critical roughness size associated with minimum deposition flux or “sag effect” was identified. This effect was more significant for nanoparticles (<1 μm) than for colloids and was numerically simulated using a Convective-Diffusion model and experimentally validated. Inclusion of flow field and hydrodynamic retardation effects explained particle deposition profiles better than when only the Derjaguin-Landau-Verwey-Overbeek (DLVO) force was considered. This work provides 1) a first comprehensive framework for describing the hydrodynamic impacts of nano-scale surface roughness on particle deposition by unifying hydrodynamic forces (using the most current approaches for describing flow field profiles and hydrodynamic retardation effects) with appropriately modified expressions for DLVO interaction energies, and gravity forces in one model and 2) a foundation for further describing the impacts of more complicated scales of deposition surface roughness on particle deposition.

A system approach for reducing the environmental impact of manufacturing and sustainability improvement of nano-scale manufacturing

NASA Astrophysics Data System (ADS)

Yuan, Yingchun

This dissertation develops an effective and economical system approach to reduce the environmental impact of manufacturing. The system approach is developed by using a process-based holistic method for upstream analysis and source reduction of the environmental impact of manufacturing. The system approach developed consists of three components of a manufacturing system: technology, energy and material, and is useful for sustainable manufacturing as it establishes a clear link between manufacturing system components and its overall sustainability performance, and provides a framework for environmental impact reductions. In this dissertation, the system approach developed is applied for environmental impact reduction of a semiconductor nano-scale manufacturing system, with three case scenarios analyzed in depth on manufacturing process improvement, clean energy supply, and toxic chemical material selection. The analysis on manufacturing process improvement is conducted on Atomic Layer Deposition of Al2O3 dielectric gate on semiconductor microelectronics devices. Sustainability performance and scale-up impact of the ALD technology in terms of environmental emissions, energy consumption, nano-waste generation and manufacturing productivity are systematically investigated and the ways to improve the sustainability of the ALD technology are successfully developed. The clean energy supply is studied using solar photovoltaic, wind, and fuel cells systems for electricity generation. Environmental savings from each clean energy supply over grid power are quantitatively analyzed, and costs for greenhouse gas reductions on each clean energy supply are comparatively studied. For toxic chemical material selection, an innovative schematic method is developed as a visual decision tool for characterizing and benchmarking the human health impact of toxic chemicals, with a case study conducted on six chemicals commonly used as solvents in semiconductor manufacturing. Reliability of

Ultrastable assembly and integration technology for ground- and space-based optical systems.

PubMed

Ressel, Simon; Gohlke, Martin; Rauen, Dominik; Schuldt, Thilo; Kronast, Wolfgang; Mescheder, Ulrich; Johann, Ulrich; Weise, Dennis; Braxmaier, Claus

2010-08-01

Optical metrology systems crucially rely on the dimensional stability of the optical path between their individual optical components. We present in this paper a novel adhesive bonding technology for setup of quasi-monolithic systems and compare selected characteristics to the well-established state-of-the-art technique of hydroxide-catalysis bonding. It is demonstrated that within the measurement resolution of our ultraprecise custom heterodyne interferometer, both techniques achieve an equivalent passive path length and tilt stability for time scales between 0.1 mHz and 1 Hz. Furthermore, the robustness of the adhesive bonds against mechanical and thermal inputs has been tested, making this new bonding technique in particular a potential option for interferometric applications in future space missions. The integration process itself is eased by long time scales for alignment, as well as short curing times.

SWS grating for UV band filter by nano-imprint

NASA Astrophysics Data System (ADS)

Lin, Jian-Shian; Liao, Ke-Hao; Chen, Chang-Tai; Lai, Chieh-Lung; Ko, Cheng-Hao

2009-05-01

Regarding to researches on manufacturing process, the fabrication of nano structures on SWS (subwavelength structured) grating are mainly produced by photo lithography. We find that UV light transmission efficiency of PET film significantly drops 50% when we put nano structures on the surface of material. In this paper, we add nano structures on the surface of PET film and create a UV band filter. Decent optical filtering effects can be achieved by combining the characteristics of PET materials with nano structures on their surfaces.

Image-rotating, 4-mirror, ring optical parametric oscillator

DOEpatents

Smith, Arlee V.; Armstrong, Darrell J.

2004-08-10

A device for optical parametric amplification utilizing four mirrors oriented in a nonplanar configuration where the optical plane formed by two of the mirrors is orthogonal to the optical plane formed by the other two mirrors and with the ratio of lengths of the laser beam paths approximately constant regardless of the scale of the device. With a cavity length of less than approximately 110 mm, a conversion efficiency of greater than 45% can be achieved.

Multi-scale reflection modulator-based optical interconnects

NASA Astrophysics Data System (ADS)

Nair, Rohit

This dissertation describes the design, analysis, and experimental validation of micro- and macro-optical components for implementing optical interconnects at multiple scales for varied applications. Three distance scales are explored: millimeter, centimeter, and meter-scales. At the millimeter-scale, we propose the use of optical interconnects at the intra-chip level. With the rapid scaling down of CMOS critical dimensions in accordance to Moore's law, the bandwidth requirements of global interconnects in microprocessors has exceeded the capabilities of metal links. These are the wires that connect the most remote parts of the chip and are disproportionately problematic in terms of chip area and power consumption. Consequently, in the mid-2000s, we saw a shift in the chip architecture: a move towards multicore designs. However, this only delays the inevitable communication bottleneck between cores. To satisfy this bandwidth, we propose to replace the global metal interconnects with optical interconnects. We propose to use the hybrid integration of silicon with GaAs/AlAs-based multiple quantum well devices as optical modulators and photodetectors along with polymeric waveguides to transport the light. We use grayscale lithography to fabricate curved facets into the waveguides to couple light into the modulators and photodetectors. Next, at the chip-to-chip level in high-performance multiprocessor computing systems, communication distances vary from a few centimeters to tens of centimeters. An optical design for coupling light from off-chip lasers to on-chip surface-normal modulators is proposed in order to implement chip-to-chip free-space optical interconnects. The method uses a dual-prism module constructed from prisms made of two different glasses. The various alignment tolerances of the proposed system are investigated and found to be well within pick-and-place accuracies. For the off-chip lasers, vertical cavity surface emitting lasers (VCSELs) are proposed

Label-free tracking of single extracellular vesicles in a nano-fluidic optical fiber (Conference Presentation)

NASA Astrophysics Data System (ADS)

van der Pol, Edwin; Weidlich, Stefan; Lahini, Yoav; Coumans, Frank A. W.; Sturk, Auguste; Nieuwland, Rienk; Schmidt, Markus A.; Faez, Sanli; van Leeuwen, Ton G.

2016-03-01

Background: Extracellular vesicles, such as exosomes, are abundantly present in human body fluids. Since the size, concentration and composition of these vesicles change during disease, vesicles have promising clinical applications, including cancer diagnosis. However, since ~70% of the vesicles have a diameter <70 nm, detection of single vesicles remains challenging. Thus far, vesicles <70 nm have only be studied by techniques that require the vesicles to be adhered to a surface. Consequently, the majority of vesicles have never been studied in their physiological environment. We present a novel label-free optical technique to track single vesicles <70 nm in suspension. Method: Urinary vesicles were contained within a single-mode light-guiding silica fiber containing a 600 nm nano-fluidic channel. Light from a diode laser (660 nm wavelength) was coupled to the fiber, resulting in a strongly confined optical mode in the nano-fluidic channel, which continuously illuminated the freely diffusing vesicles inside the channel. The elastic light scattering from the vesicles, in the direction orthogonal to the fiber axis, was collected using a microscope objective (NA=0.95) and imaged with a home-built microscope. Results: We have tracked single urinary vesicles as small as 35 nm by elastic light scattering. Please note that vesicles are low-refractive index (n<1.4) particles, which we confirmed by combining data on thermal diffusion and light scattering cross section. Conclusions: For the first time, we have studied vesicles <70 nm freely diffusing in suspension. The ease-of-use and performance of this technique support its potential for vesicle-based clinical applications.

SU-E-T-87: The Effect of Bleaching Wavelengths on the Regeneration of the Optically Stimulated Luminescence Signal of NanoDot Dosimeters Pre-Exposed to High-Doses.

PubMed

Omotayo, A; Cygler, J; Sawakuchi, G

2012-06-01

To investigate the effect of bleaching wavelengths on the regeneration of optically stimulated luminescence (OSL) signals in Al 2 O 3 :C nanoDot dosimeters pre-exposed to high doses. Regeneration is the increase in the OSL signal during storage of a bleached nanoDot that was previously pre-exposed to a high dose. This phenomenon affects the accuracy of a calibration protocol proposed by Jursinic 2010 (Med. Phys. 37:102) in which pre-exposure of nanoDots to a high-dose was used to minimize changes in the sensitivity of the detector as a function of accumulated dose. Al 2 O 3 :C OSLDs of the type nanoDot were used throughout this study. Readout was performed using the microStar reader. Bleaching of the OSLDs was performed with four 26 W fluorescent light bulbs in two modes: (i) directly under the lamps; and (ii) with the aid of a long-pass optical filter placed over the nanoDots, partially blocking wavelengths below 495 nm. Eighteen nanoDots were pre-exposed to 1 kGy dose. Then the pre-exposed nanoDots were bleached in two sets of 9 to very low residual OSL signals using bleaching modes (i) and (ii) for 12 h and 45 h, respectively. The nanoDots were then stored in dark and readout after various time intervals to monitor the regeneration of the OSL signal. We fitted the regeneration of the OSL signal using a saturation function and obtained rise-time values of 563 h and 630 h, for bleaching modes (i) and (ii), respectively. At the saturation level, the equivalent doses were about 1.18 Gy and 0.38 Gy for modes (i) and (ii), respectively. The regeneration rates of nanoDot OSLDs pre-exposed to high doses depend on the bleaching light wavelength used to reset the detectors. A bleaching source that has a low component of wavelengths below 495 nm can minimize the regeneration of the OSL signal. Natural Sciences and Engineering Research Council of Canada. © 2012 American Association of Physicists in Medicine.

Beam splitter and method for generating equal optical path length beams

DOEpatents

Qian, Shinan; Takacs, Peter

2003-08-26

The present invention is a beam splitter for splitting an incident beam into first and second beams so that the first and second beams have a fixed separation and are parallel upon exiting. The beam splitter includes a first prism, a second prism, and a film located between the prisms. The first prism is defined by a first thickness and a first perimeter which has a first major base. The second prism is defined by a second thickness and a second perimeter which has a second major base. The film is located between the first major base and the second major base for splitting the incident beam into the first and second beams. The first and second perimeters are right angle trapezoidal shaped. The beam splitter is configured for generating equal optical path length beams.

My Path Into X-Ray, Optics and Pressure: Experiences and Achievements

NASA Astrophysics Data System (ADS)

Evans, William

2013-04-01

A successful career path in science is rarely formulaic or achieved by following a predefined set of actions. Sustained commitment, perseverance, performance and relationships are all key ingredients. Judicious selection of opportunities (research projects, employers, etc.) can lead to significant scientific accomplishments and career advancements. In this presentation I will review the trajectory of my scientific career spanning my experiences from the Westinghouse STS and ISEF, through Caltech and Harvard to my current position of High Pressure Physics Group Leader at Lawrence Livermore National Laboratory. I will discuss my involvement in some exciting research projects using x-ray synchrotron sources and optical spectroscopy to study static and dynamic properties of materials at high-pressures. In addition, I will share my perspectives on the importance of excellence, preparedness and the value of professional relationships.

Optimization of perfluoro nano-scale emulsions: the importance of particle size for enhanced oxygen transfer in biomedical applications.

PubMed

Fraker, Christopher A; Mendez, Armando J; Inverardi, Luca; Ricordi, Camillo; Stabler, Cherie L

2012-10-01

Nano-scale emulsification has long been utilized by the food and cosmetics industry to maximize material delivery through increased surface area to volume ratios. More recently, these methods have been employed in the area of biomedical research to enhance and control the delivery of desired agents, as in perfluorocarbon emulsions for oxygen delivery. In this work, we evaluate critical factors for the optimization of PFC emulsions for use in cell-based applications. Cytotoxicity screening revealed minimal cytotoxicity of components, with the exception of one perfluorocarbon utilized for emulsion manufacture, perfluorooctylbromide (PFOB), and specific w% limitations of PEG-based surfactants utilized. We optimized the manufacture of stable nano-scale emulsions via evaluation of: component materials, emulsification time and pressure, and resulting particle size and temporal stability. The initial emulsion size was greatly dependent upon the emulsion surfactant tested, with pluronics providing the smallest size. Temporal stability of the nano-scale emulsions was directly related to the perfluorocarbon utilized, with perfluorotributylamine, FC-43, providing a highly stable emulsion, while perfluorodecalin, PFD, coalesced over time. The oxygen mass transfer, or diffusive permeability, of the resulting emulsions was also characterized. Our studies found particle size to be the critical factor affecting oxygen mass transfer, as increased micelle size resulted in reduced oxygen diffusion. Overall, this work demonstrates the importance of accurate characterization of emulsification parameters in order to generate stable, reproducible emulsions with the desired bio-delivery properties. Copyright © 2012 Elsevier B.V. All rights reserved.

Tortuous Pore Path Through the Glaucomatous Lamina Cribrosa.

PubMed

Wang, Bo; Lucy, Katie A; Schuman, Joel S; Sigal, Ian A; Bilonick, Richard A; Lu, Chen; Liu, Jonathan; Grulkowski, Ireneusz; Nadler, Zachary; Ishikawa, Hiroshi; Kagemann, Larry; Fujimoto, James G; Wollstein, Gadi

2018-05-08

The lamina cribrosa is a primary site of damage in glaucoma. While mechanical distortion is hypothesized to cause reduction of axoplasmic flow, little is known about how the pores, which contains the retinal ganglion cell axons, traverse the lamina cribrosa. We investigated lamina cribrosa pore paths in vivo to quantify differences in tortuosity of pore paths between healthy and glaucomatous eyes. We imaged 16 healthy, 23 glaucoma suspect and 48 glaucomatous eyes from 70 subjects using a swept source optical coherence tomography system. The lamina cribrosa pores were automatically segmented using a previously described segmentation algorithm. Individual pore paths were automatically tracked through the depth of the lamina cribrosa using custom software. Pore path convergence to the optic nerve center and tortuosity was quantified for each eye. We found that lamina cribrosa pore pathways traverse the lamina cribrosa closer to the optic nerve center along the depth of the lamina cribrosa regardless of disease severity or diagnostic category. In addition, pores of glaucoma eyes take a more tortuous path through the lamina cribrosa compared to those of healthy eyes, suggesting a potential mechanism for reduction of axoplasmic flow in glaucoma.

Asymmetric transmission and optical low-pass filtering in a stack of random media with graded transport mean free path

NASA Astrophysics Data System (ADS)

Bingi, J.; Hemalatha, M.; Anita, R. W.; Vijayan, C.; Murukeshan, V. M.

2015-11-01

Light transport and the physical phenomena related to light propagation in random media are very intriguing, they also provide scope for new paradigms of device functionality, most of which remain unexplored. Here we demonstrate, experimentally and by simulation, a novel kind of asymmetric light transmission (diffusion) in a stack of random media (SRM) with graded transport mean free path. The structure is studied in terms of transmission, of photons propagated through and photons generated within the SRM. It is observed that the SRM exhibits asymmetric transmission property with a transmission contrast of 0.25. In addition, it is shown that the SRM works as a perfect optical low-pass filter with a well-defined cutoff wavelength at 580 nm. Further, the photons generated within the SRM found to exhibit functionality similar to an optical diode with a transmission contrast of 0.62. The basis of this functionality is explained in terms of wavelength dependent photon randomization and the graded transport mean free path of SRM.

Optical Circuit Switched Protocol

NASA Technical Reports Server (NTRS)

Monacos, Steve P. (Inventor)

2000-01-01

The present invention is a system and method embodied in an optical circuit switched protocol for the transmission of data through a network. The optical circuit switched protocol is an all-optical circuit switched network and includes novel optical switching nodes for transmitting optical data packets within a network. Each optical switching node comprises a detector for receiving the header, header detection logic for translating the header into routing information and eliminating the header, and a controller for receiving the routing information and configuring an all optical path within the node. The all optical path located within the node is solely an optical path without having electronic storage of the data and without having optical delay of the data. Since electronic storage of the header is not necessary and the initial header is eliminated by the first detector of the first switching node. multiple identical headers are sent throughout the network so that subsequent switching nodes can receive and read the header for setting up an optical data path.

Linear arrangements of nano-scale ferromagnetic particles spontaneously formed in a copper-base Cu-Ni-Co alloy

NASA Astrophysics Data System (ADS)

Sakakura, Hibiki; Kim, Jun-Seop; Takeda, Mahoto

2018-03-01

We have investigated the influence of magnetic interactions on the microstructural evolution of nano-scale granular precipitates formed spontaneously in an annealed Cu-20at%Ni-5at%Co alloy and the associated changes of magnetic properties. The techniques used included transmission electron microscopy, superconducting quantum interference device (SQUID) magnetometry, magneto-thermogravimetry (MTG), and first-principles calculations based on the method of Koster-Korringa-Rostker with the coherent potential approximation. Our work has revealed that the nano-scale spherical and cubic precipitates which formed on annealing at 873 K and 973 K comprise mainly cobalt and nickel with a small amount of copper, and are arranged in the 〈1 0 0〉 direction of the copper matrix. The SQUID and MTG measurements suggest that magnetic properties such as coercivity and Curie temperature are closely correlated with the microstructure. The combination of results suggests that magnetic interactions between precipitates during annealing can explain consistently the observed precipitation phenomena.

Seeing with the nano-eye: accessing structure, function, and dynamics of matter on its natural length and time scales

NASA Astrophysics Data System (ADS)

Raschke, Markus

2015-03-01

To understand and ultimately control the properties of most functional materials, from molecular soft-matter to quantum materials, requires access to the structure, coupling, and dynamics on the elementary time and length scales that define the microscopic interactions in these materials. To gain the desired nanometer spatial resolution with simultaneous spectroscopic specificity we combine scanning probe microscopy with different optical, including coherent, nonlinear, and ultrafast spectroscopies. The underlying near-field interaction mediated by the atomic-force or scanning tunneling microscope tip provides the desired deep-sub wavelength nano-focusing enabling few-nm spatial resolution. I will introduce our generalization of the approach in terms of the near-field impedance matching to a quantum system based on special optical antenna-tip designs. The resulting enhanced and qualitatively new forms of light-matter interaction enable measurements of quantum dynamics in an interacting environment or to image the electromagnetic local density of states of thermal radiation. Other applications include the inter-molecular coupling and dynamics in soft-matter hetero-structures, surface plasmon interferometry as a probe of electronic structure and dynamics in graphene, and quantum phase transitions in correlated electron materials. These examples highlight the general applicability of the new near-field microscopy approach, complementing emergent X-ray and electron imaging tools, aiming towards the ultimate goal of probing matter on its most elementary spatio-temporal level.

Convergence Science in a Nano World

PubMed Central

Cady, Nathaniel

2013-01-01

Convergence is a new paradigm that brings together critical advances in the life sciences, physical sciences and engineering. Going beyond traditional “interdisciplinary” studies, “convergence” describes the culmination of truly integrated research and development, yielding revolutionary advances in both scientific research and new technologies. At its core, nanotechnology embodies these elements of convergence science by bringing together multiple disciplines with the goal of creating innovative and groundbreaking technologies. In the biological and biomedical sciences, nanotechnology research has resulted in dramatic improvements in sensors, diagnostics, imaging, and even therapeutics. In particular, there is a current push to examine the interface between the biological world and micro/nano-scale systems. For example, my laboratory is developing novel strategies for spatial patterning of biomolecules, electrical and optical biosensing, nanomaterial delivery systems, cellular patterning techniques, and the study of cellular interactions with nano-structured surfaces. In this seminar, I will give examples of how convergent research is being applied to three major areas of biological research &endash; cancer diagnostics, microbiology, and DNA-based biosensing. These topics will be presented as case studies, showing the benefits (and challenges) of multi-disciplinary, convergent research and development.

Enhanced electronic excitation energy transfer between dye molecules incorporated in nano-scale media with apparent fractal dimensionality

NASA Astrophysics Data System (ADS)

Yefimova, Svetlana L.; Rekalo, Andrey M.; Gnap, Bogdan A.; Viagin, Oleg G.; Sorokin, Alexander V.; Malyukin, Yuri V.

2014-09-01

In the present study, we analyze the efficiency of Electronic Excitation Energy Transfer (EEET) between two dyes, an energy donor (D) and acceptor (A), concentrated in structurally heterogeneous media (surfactant micelles, liposomes, and porous SiO2 matrices). In all three cases, highly effective EEET in pairs of dyes has been found and cannot be explained by Standard Förster-type theory for homogeneous solutions. Two independent approaches based on the analysis of either the D relative quantum yield () or the D fluorescence decay have been used to study the deviation of experimental results from the theoretical description of EEET process. The observed deviation is quantified by the apparent fractal distribution of molecules parameter . We conclude that the highly effective EEET observed in the nano-scale media under study can be explained by both forced concentration of the hydrophobic dyes within nano-volumes and non-uniform cluster-like character of the distribution of D and A dye molecules within nano-volumes.

EDITORIAL: Breeding new science by coupling photons with `nano'

NASA Astrophysics Data System (ADS)

Zheludev, Nikolay; Stockman, Mark; Zayats, Anatoly

2006-04-01

The new field of `nanophotonics' is concerned with the generation, transport, routing and detection of light in sub-wavelength structures. There is nothing new in the desire to use small structures to control waves that are much bigger than the structures, and the science of acoustics has been dealing with this problem since the early days of musical instruments. What makes nanophotonics so special is that it claims for optics the unexplored playfield of dimensions between those of objects the human eye can see with a lens, and those of the invisible elementary building blocks of the material world, molecules and atoms. Nanophotonics is a synthetic discipline that breaks into the fields of electrodynamics, solid state physics and laser physics. In growing from these disciplines it takes ideas from them, for instance from solid state physics by drawing analogies between electrons in crystals and photons in nanostructures, and from laser physics and traditional nonlinear optics by achieving strong fields not through an increase in optical power, but through its concentration. From an engineering perspective, nanophotonics promises to develop optical functionality on the smallest possible size scale (thus allowing for ultra-high-density integration), at the lowest possible energy level (thus allowing for single photon all-optical devices), and on the shortest possible timescale (thus allowing for optical devices operating within a single period of an optical wave). In this special issue we are, however, concerned with the fundamental aspects of nanophotonics, i.e. the physics that underpins these new, mind-boggling nanophotonic applications. This special issue opens with 4 articles derived from lectures at the Summer School Photonic Metamaterials: from Micro to Nanoscale, Erice, Italy, 1 7 August 2005. These reviews establish the hierarchy of nanophotonic structures and relevant length scales, explore wave interactions in nanostructured media, and examine nanophotonic

Scaling laws for light-weight optics

NASA Technical Reports Server (NTRS)

Valente, Tina M.

1990-01-01

Scaling laws for light-weight optical systems are examined. A cubic relationship between mirror diameter and weight has been suggested and used by many designers of optical systems as the best description for all light-weight mirrors. A survey of existing light-weight systems in the open literature has been made to clarify this issue. Fifty existing optical systems were surveyed with all varieties of light-weight mirrors including glass and beryllium structured mirrors, contoured mirrors, and very thin solid mirrors. These mirrors were then categorized and weight to diameter ratio was plotted to find a best fit curve for each case. A best fitting curve program tests nineteen different equations and ranks a 'goodness of fit' for each of these equations. The resulting relationship found for each light-weight mirror category helps to quantify light-weight optical systems and methods of fabrication and provides comparisons between mirror types.

Development of a visible light transmission (VLT) measurement system using an open-path optical method

NASA Astrophysics Data System (ADS)

Nurulain, S.; Manap, H.

2017-09-01

This paper describes about a visible light transmission (VLT) measurement system using an optical method. VLT rate plays an important role in order to determine the visibility of a medium. Current instrument to measure visibility has a gigantic set up, costly and mostly fails to function at low light condition environment. This research focuses on the development of a VLT measurement system using a simple experimental set-up and at a low cost. An open path optical technique is used to measure a few series of known-VLT thin film that act as sample of different visibilities. This measurement system is able to measure the light intensity of these thin films within the visible light region (535-540 nm) and the response time is less than 1s.

Characterization of the Los Alamos IPG YLR-6000 fiber laser using multiple optical paths and laser focusing optics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Milewski, John O; Bernal, John E

2009-01-01

Fiber laser technology has been identified as the replacement power source for the existing Los Alamos TA-55 production laser welding system. An IPG YLR-6000 fiber laser was purchased, installed at SM-66 R3, and accepted in February 2008. No characterization of the laser and no welding was performed in the Feb 2008 to May 2009 interval. T. Lienert and J. Bernal (Ref. 1, July 2009) determined the existing 200 mm Rofin collimator and focus heads used with the Rofin diode pumped lasers were inadequate for use with the IPG laser due to clipping of the IPG laser beam. Further efforts inmore » testing of the IPG laser with Optoskand fiber delivery optics and a Rofin 120 mm collimator proved problematic due to optical fiber damage. As a result, IPG design optical fibers were purchased as replacements for subsequent testing. Within the same interval, an IPG fiber-to-fiber (F2F) connector, custom built for LANL, (J. Milewski, S. Gravener, Ref.2) was demonstrated and accepted at IPG Oxford, MA in August 2009. An IPG service person was contracted to come to LANL to assist in the installation, training, troubleshooting and characterization of the multiple beam paths and help perform laser head optics characterization. The statement of work is provided below: In summary the laser system, optical fibers, F2F connector, Precitec head, and a modified Rofin type (w/120mm Optoskand collimator) IWindowIBoot system focus head (Figure 1) were shown to perform well at powers up to 6 kW CW. Power measurements, laser spot size measurements, and other characterization data and lessons learned are contained within this report. In addition, a number of issues were identified that will require future resolution.« less

Slant Path Low Visibility Atmospheric Conditions.

DTIC Science & Technology

1980-09-01

situation. a) An optical propagation slant test path , of a length over which infrared transmissometer measurements can be made that are in a magnitude...transmission measure - ments which are close to 100% and therefore do not accurately relate to absolute transmissivity. A path which is too long will result in...is available for measurement of backscatter cross section along the chosen transmissometer path . 3. Rough Cross Cut of the Works unde Contract in

Formation Of Nano Layered Lamellar Structure In a Processed γ-TiAl Based Alloy

NASA Astrophysics Data System (ADS)

Heshmati-Manesh, S.; Shakoorian, H.; Armaki, H. Ghassemi; Ahmadabadi, M. Nili

2009-06-01

In this research, microstructures of an intermetallic alloy based on γ-TiAl has been investigated by optical and transmission electron microscopy. Samples of Ti-47Al-2Cr alloy were subjected to either a cyclic heat treatment or thermomechanical treatment with the aim of microstructural refinement. In both cases it was found that very fine lamellar structure with an interlamellar spacing in the nano scale is formed. Upon cyclic heat treatment, nano layers of α2 and γ ordered intermetallic phases were either formed during rapid cooling cycle in competition with massive structure formation, or formed as secondary lamellar structure during final stages of cyclic heat treatment. Also, TEM observations in hot forged specimens with initial lamellar structure revealed that micro twins form during the deformation within lamellar structure with twinning plates parallel to lamellar interfaces. Concurrent dynamic recrystallisation results in a nano layered structure with an interlamellar spacing of less than 100 nm.

Measurement profiles of nano-scale ion beam for optimized radiation energy losses

NASA Astrophysics Data System (ADS)

Woo, T. H.; Cho, H. S.

2011-10-01

The behavior of charged particles is investigated for nano-scale ion beam therapy using a medical accelerator. Computational work is performed for the Bragg-peak simulation, which is focused on human organ material of pancreas and thyroid. The Results show that the trends of the dose have several different kinds of distributions. Before constructing a heavy ion collider, this study can give us the reliability of the therapeutic effect. Realistic treatment using human organs is calculated in a simple and cost effective manner using the computational code, the Stopping and Range of Ions in Matter 2008 (SRIM 2008). Considering the safety of the therapy, it is suggested to give a patient orient planning of the cancer therapy. The energy losses in ionization and phonon are analyzed, which are the behaviors in the molecular level nano-scopic investigation. The different fluctuations are shown at 150 MeV, where the lowest temperature is found in proton and pancreas case. Finally, the protocol for the radiation therapy is constructed by the simulation in which the procedure for a better therapy is selected. An experimental measurement incorporated with the simulations could be programmed by this protocol.

Optical band gap determination of calcium doped lanthanum manganite nano particle tailored with polypyrrole

NASA Astrophysics Data System (ADS)

Gopalakrishna, Smitha Mysore; Murugendrappa, Malalkere Veerappa

2018-05-01

In this paper we bring forth the effect of La0.7Ca0.3MnO3 (LCM) perovskite nano particle on the optical band gap in composition with conducting Polypyrrole (PPy) prepared by chemical oxidation method. The morphology and crystalline phase were determined by SEM, TEM and X-Ray diffraction studies. The Optical band gap studies were analyzed using the UV-VIS spectrometer scanned in the range 200 nm to 600 nm for pure PPy and PPy/LCM composites. There is a characteristic peak observed for the composites situated around 315 nm for pure PPy, PPy/LCM10 and PPy/LCM50. But for higher compositions of LCM weight percentage like 30%, 40% and 50% the peak shift slightly to higher wavelength side. The peak shifts to 320 nm, 325 nm and 335 nm respectively. The optical band gap increased for Pure PPy, PPy/LCM10 and PPy/LCM20 and found to decrease gradually for PPy/LCM30, PPy/LCM40 and PPy/LCM50. The studies suggest that LCM composition in the PPy chain has a role in modifying the wavelength and in turn its band gap. The study may find application in organic devices working at high frequency and voltage.

Detecting Nano-Scale Vibrations in Rotating Devices by Using Advanced Computational Methods

PubMed Central

del Toro, Raúl M.; Haber, Rodolfo E.; Schmittdiel, Michael C.

2010-01-01

This paper presents a computational method for detecting vibrations related to eccentricity in ultra precision rotation devices used for nano-scale manufacturing. The vibration is indirectly measured via a frequency domain analysis of the signal from a piezoelectric sensor attached to the stationary component of the rotating device. The algorithm searches for particular harmonic sequences associated with the eccentricity of the device rotation axis. The detected sequence is quantified and serves as input to a regression model that estimates the eccentricity. A case study presents the application of the computational algorithm during precision manufacturing processes. PMID:22399918

The effect of oxide shell thickness on the structural, electronic, and optical properties of Si-SiO{sub 2} core-shell nano-crystals: A (time dependent)density functional theory study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nazemi, Sanaz, E-mail: s.nazemi@ut.ac.ir, E-mail: pourfath@ut.ac.ir; Soleimani, Ebrahim Asl; Pourfath, Mahdi, E-mail: s.nazemi@ut.ac.ir, E-mail: pourfath@ut.ac.ir

2016-04-14

Due to their tunable properties, silicon nano-crystals (NC) are currently being investigated. Quantum confinement can generally be employed for size-dependent band-gap tuning at dimensions smaller than the Bohr radius (∼5 nm for silicon). At the nano-meter scale, however, increased surface-to-volume ratio makes the surface effects dominant. Specifically, in Si-SiO{sub 2} core-shell semiconductor NCs the interfacial transition layer causes peculiar electronic and optical properties, because of the co-existence of intermediate oxidation states of silicon (Si{sup n+}, n = 0–4). Due to the presence of the many factors involved, a comprehensive understanding of the optical properties of these NCs has not yet been achieved. Inmore » this work, Si-SiO{sub 2} NCs with a diameter of 1.1 nm and covered by amorphous oxide shells with thicknesses between 2.5 and 4.75 Å are comprehensively studied, employing density functional theory calculations. It is shown that with increased oxide shell thickness, the low-energy part of the optical transition spectrum of the NC is red shifted and attenuated. Moreover, the absorption coefficient is increased in the high-energy part of the spectrum which corresponds to SiO{sub 2} transitions. Structural examinations indicate a larger compressive stress on the central silicon cluster with a thicker oxide shell. Examination of the local density of states reveals the migration of frontier molecular orbitals from the oxide shell into the silicon core with the increase of silica shell thickness. The optical and electrical properties are explained through the analysis of the density of states and the spatial distribution of silicon sub-oxide species.« less

Alternative Path Communication in Wide-Scale Cluster-Tree Wireless Sensor Networks Using Inactive Periods

PubMed Central

Leão, Erico; Montez, Carlos; Moraes, Ricardo; Portugal, Paulo; Vasques, Francisco

2017-01-01

The IEEE 802.15.4/ZigBee cluster-tree topology is a suitable technology to deploy wide-scale Wireless Sensor Networks (WSNs). These networks are usually designed to support convergecast traffic, where all communication paths go through the PAN (Personal Area Network) coordinator. Nevertheless, peer-to-peer communication relationships may be also required for different types of WSN applications. That is the typical case of sensor and actuator networks, where local control loops must be closed using a reduced number of communication hops. The use of communication schemes optimised just for the support of convergecast traffic may result in higher network congestion and in a potentially higher number of communication hops. Within this context, this paper proposes an Alternative-Route Definition (ARounD) communication scheme for WSNs. The underlying idea of ARounD is to setup alternative communication paths between specific source and destination nodes, avoiding congested cluster-tree paths. These alternative paths consider shorter inter-cluster paths, using a set of intermediate nodes to relay messages during their inactive periods in the cluster-tree network. Simulation results show that the ARounD communication scheme can significantly decrease the end-to-end communication delay, when compared to the use of standard cluster-tree communication schemes. Moreover, the ARounD communication scheme is able to reduce the network congestion around the PAN coordinator, enabling the reduction of the number of message drops due to queue overflows in the cluster-tree network. PMID:28481245

Alternative Path Communication in Wide-Scale Cluster-Tree Wireless Sensor Networks Using Inactive Periods.

PubMed

Leão, Erico; Montez, Carlos; Moraes, Ricardo; Portugal, Paulo; Vasques, Francisco

2017-05-06

The IEEE 802.15.4/ZigBee cluster-tree topology is a suitable technology to deploy wide-scale Wireless Sensor Networks (WSNs). These networks are usually designed to support convergecast traffic, where all communication paths go through the PAN (Personal Area Network) coordinator. Nevertheless, peer-to-peer communication relationships may be also required for different types of WSN applications. That is the typical case of sensor and actuator networks, where local control loops must be closed using a reduced number of communication hops. The use of communication schemes optimised just for the support of convergecast traffic may result in higher network congestion and in a potentially higher number of communication hops. Within this context, this paper proposes an Alternative-Route Definition (ARounD) communication scheme for WSNs. The underlying idea of ARounD is to setup alternative communication paths between specific source and destination nodes, avoiding congested cluster-tree paths. These alternative paths consider shorter inter-cluster paths, using a set of intermediate nodes to relay messages during their inactive periods in the cluster-tree network. Simulation results show that the ARounD communication scheme can significantly decrease the end-to-end communication delay, when compared to the use of standard cluster-tree communication schemes. Moreover, the ARounD communication scheme is able to reduce the network congestion around the PAN coordinator, enabling the reduction of the number of message drops due to queue overflows in the cluster-tree network.

The nano-epsilon dot method for strain rate viscoelastic characterisation of soft biomaterials by spherical nano-indentation.

PubMed

Mattei, G; Gruca, G; Rijnveld, N; Ahluwalia, A

2015-10-01

Nano-indentation is widely used for probing the micromechanical properties of materials. Based on the indentation of surfaces using probes with a well-defined geometry, the elastic and viscoelastic constants of materials can be determined by relating indenter geometry and measured load and displacement to parameters which represent stress and deformation. Here we describe a method to derive the viscoelastic properties of soft hydrated materials at the micro-scale using constant strain rates and stress-free initial conditions. Using a new self-consistent definition of indentation stress and strain and corresponding unique depth-independent expression for indentation strain rate, the epsilon dot method, which is suitable for bulk compression testing, is transformed to nano-indentation. We demonstrate how two materials can be tested with a displacement controlled commercial nano-indentor using the nano-espilon dot method (nano-ε̇M) to give values of instantaneous and equilibrium elastic moduli and time constants with high precision. As samples are tested in stress-free initial conditions, the nano-ε̇M could be useful for characterising the micro-mechanical behaviour of soft materials such as hydrogels and biological tissues at cell length scales. Copyright © 2015 Elsevier Ltd. All rights reserved.

Comparing the Efficacy of Three Different Nano-scale Bone Substitutes: In vivo Study.

PubMed

Razavi, Sayed Mohammad; Rismanchian, Mansour; Jafari-Pozve, Nasim; Nosouhian, Saied

2017-01-01

Synthetic biocompatible bone substitutions have been used widely for bone tissue regeneration as they are safe and effective. The aim of this animal study is to compare the effectiveness of three different biocompatible bone substitutes, including nano-hydroxyapatite (nano-HA) nano-bioglass (nano-BG) and forstrite scaffolds. In this interventional and experimental study, four healthy dogs were anesthetized, and the first to fourth premolars were extracted in each quadrant. After healing, the linear incision on the crestal ridge from molar to anterior segment prepared in each quadrant and 16 defects in each dog were prepared. Nano-HA, nano-BG, and forstrite scaffold was prepared according to the size of defects and placed in the 12 defects randomly, four defects remained as a control group. The dogs were sacrificed in four time intervals (15, 30, 45, and 60 days after) and the percentage of different types of regenerated bones (lamellar and woven) and connective tissue were recorded in histological process. The data were analyzed using Mann-Whitney test (α = 0.05). The difference in nano-HA and nano-BG with the control group was significant in three-time intervals regarding the amount of bone formation ( P < 0.01). After 15 days, the nano-HA showed the highest amount of woven and lamellar bone regeneration (18.37 ± 1.06 and 30.44 ± 0.54). Nano-HA and nano-BG groups showed a significant amount of bone regeneration, especially after 30 days, but paying more surveys and observation to these materials as bone substitutes seem to be needed.

Extension of nano-scaled exploration into solution/liquid systems using tip-enhanced Raman scattering

NASA Astrophysics Data System (ADS)

Pienpinijtham, Prompong; Vantasin, Sanpon; Kitahama, Yasutaka; Ekgasit, Sanong; Ozaki, Yukihiro

2017-08-01

This review shows updated experimental cases of tip-enhanced Raman scattering (TERS) operated in solution/liquid systems. TERS in solution/liquid is still infancy, but very essential and challenging because crucial and complicated biological processes such as photosynthesis, biological electron transfer, and cellular respiration take place and undergo in water, electrolytes, or buffers. The measurements of dry samples do not reflect real activities in those kinds of systems. To deeply understand them, TERS in solution/liquid is needed to be developed. The first TERS experiment in solution/liquid is successfully performed in 2009. After that time, TERS in solution/liquid has gradually been developed. It shows a potential to study structural changes of biomembranes, opening the world of dynamic living cells. TERS is combined with electrochemical techniques, establishing electrochemical TERS (EC-TERS) in 2015. EC-TERS creates an interesting path to fulfil the knowledge about electrochemical-related reactions or processes. TERS tip can be functionalized with sensitive molecules to act as a "surface-enhanced Raman scattering (SERS) at tip" for investigating distinct properties of systems in solution/liquid e.g., pH and electron transfer mechanism. TERS setup is continuously under developing. Versatile geometry of the setup and a guideline of a systematic implementation for a setup of TERS in solution/liquid are proposed. New style of setup is also reported for TERS imaging in solution/liquid. From all of these, TERS in solution/liquid will expand a nano-scaled exploration into solution/liquid systems of various fields e.g., energy storages, catalysts, electronic devices, medicines, alternative energy sources, and build a next step of nanoscience and nanotechnology.

Application Of Positron Beams For The Characterization Of Nano-scale Pores In Thin Films

NASA Astrophysics Data System (ADS)

Hirata, K.; Ito, K.; Kobayashi, Y.; Suzuki, R.; Ohdaira, T.; Eijt, S. W. H.; Schut, H.; van Veen, A.

2003-08-01

We applied three positron annihilation techniques, positron 3γ-annihilation spectroscopy, positron annihilation lifetime spectroscopy, and angular correlation of annihilation radiation, to the characterization of nano-scale pores in thin films by combining them with variable-energy positron beams. Characterization of pores in thin films is an important part of the research on various thin films of industrial importance. The results of our recent studies on pore characterization of thin films by positron beams will be reported here.

Order of magnitude improvement of nano-contact spin torque nano-oscillator performance.

PubMed

Banuazizi, Seyed Amir Hossein; Sani, Sohrab R; Eklund, Anders; Naiini, Maziar M; Mohseni, Seyed Majid; Chung, Sunjae; Dürrenfeld, Philipp; Malm, B Gunnar; Åkerman, Johan

2017-02-02

Spin torque nano-oscillators (STNO) represent a unique class of nano-scale microwave signal generators and offer a combination of intriguing properties, such as nano sized footprint, ultrafast modulation rates, and highly tunable microwave frequencies from 100 MHz to close to 100 GHz. However, their low output power and relatively high threshold current still limit their applicability and must be improved. In this study, we investigate the influence of the bottom Cu electrode thickness (t Cu ) in nano-contact STNOs based on Co/Cu/NiFe GMR stacks and with nano-contact diameters ranging from 60 to 500 nm. Increasing t Cu from 10 to 70 nm results in a 40% reduction of the threshold current, an order of magnitude higher microwave output power, and close to two orders of magnitude better power conversion efficiency. Numerical simulations of the current distribution suggest that these dramatic improvements originate from a strongly reduced lateral current spread in the magneto-dynamically active region.

Spatial height directed microfluidic synthesis of transparent inorganic upconversion nano film

NASA Astrophysics Data System (ADS)

Liu, Xiaoxia; Zhu, Cheng; Liao, Wei; Jin, Junyang; Ni, Yaru; Lu, Chunhua; Xu, Zhongzi

2017-11-01

A microfluidic-based synthesis of an inorganic upconversion nano film has been developed with a large area of dense-distributed NaYF4 crystal grains in a silica glass micro-reactor and the film exhibits high transparence, strong upconversion luminescence and robust adhesion with the substrate. The spatial heights of micro-reactors are tuned between 31 and 227 mm, which can regulate flow regimes. The synergistic effect of spatial height and fluid regime is put forward, which influences diffusion paths and assembly ways of different precursor molecules and consequently directs final distributions and morphologies of crystal grains, as well as optical properties due to diversity of surface and thickness of films. The spatial height of 110 mm is advantageous for high transmittance of upconversion film due to the flat surface and appropriate film thickness of 67 nm. The height of 150 mm is in favor of uniform distribution of upconversion fluorescence and achieving the strongest fluorescence due to minimized optical loss. Such a transparent upconversion film with a large area of uniform distribution is promising to promote the application of upconversion materials and spatial height directed microfluidic regime have a certain significance on many microfluidic synthesis.

Atomic-scale defects and electronic properties of a transferred synthesized MoS2 monolayer

NASA Astrophysics Data System (ADS)

Delač Marion, Ida; Čapeta, Davor; Pielić, Borna; Faraguna, Fabio; Gallardo, Aurelio; Pou, Pablo; Biel, Blanca; Vujičić, Nataša; Kralj, Marko

2018-07-01

MoS2 monolayer samples were synthesized on a SiO2/Si wafer and transferred to Ir(111) for nano-scale characterization. The samples were extensively characterized during every step of the transfer process, and MoS2 on the final substrate was examined down to the atomic level by scanning tunneling microscopy (STM). The procedures conducted yielded high-quality monolayer MoS2 of milimeter-scale size with an average defect density of 2 × 1013 cm–2. The lift-off from the growth substrate was followed by a release of the tensile strain, visible in a widening of the optical band gap measured by photoluminescence. Subsequent transfer to the Ir(111) surface led to a strong drop of this optical signal but without further shifts of characteristic peaks. The electronic band gap was measured by scanning tunneling spectroscopy (STS), revealing n-doping and lateral nano-scale variations. The combined use of STM imaging and density functional theory (DFT) calculations allows us to identify the most recurring point-like defects as S vacancies.

Atomic-scale defects and electronic properties of a transferred synthesized MoS2 monolayer.

PubMed

Delač Marion, Ida; Čapeta, Davor; Pielić, Borna; Faraguna, Fabio; Gallardo, Aurelio; Pou, Pablo; Biel, Blanca; Vujičić, Nataša; Kralj, Marko

2018-07-27

MoS 2 monolayer samples were synthesized on a SiO 2 /Si wafer and transferred to Ir(111) for nano-scale characterization. The samples were extensively characterized during every step of the transfer process, and MoS 2 on the final substrate was examined down to the atomic level by scanning tunneling microscopy (STM). The procedures conducted yielded high-quality monolayer MoS 2 of milimeter-scale size with an average defect density of 2 × 10 13 cm -2 . The lift-off from the growth substrate was followed by a release of the tensile strain, visible in a widening of the optical band gap measured by photoluminescence. Subsequent transfer to the Ir(111) surface led to a strong drop of this optical signal but without further shifts of characteristic peaks. The electronic band gap was measured by scanning tunneling spectroscopy (STS), revealing n-doping and lateral nano-scale variations. The combined use of STM imaging and density functional theory (DFT) calculations allows us to identify the most recurring point-like defects as S vacancies.

Sub-micron phase coexistence in small-molecule organic thin films revealed by infrared nano-imaging

PubMed Central

Westermeier, Christian; Cernescu, Adrian; Amarie, Sergiu; Liewald, Clemens; Keilmann, Fritz; Nickel, Bert

2014-01-01

Controlling the domain size and degree of crystallization in organic films is highly important for electronic applications such as organic photovoltaics, but suitable nanoscale mapping is very difficult. Here we apply infrared-spectroscopic nano-imaging to directly determine the local crystallinity of organic thin films with 20-nm resolution. We find that state-of-the-art pentacene films (grown on SiO2 at elevated temperature) are structurally not homogeneous but exhibit two interpenetrating phases at sub-micrometre scale, documented by a shifted vibrational resonance. We observe bulk-phase nucleation of distinct ellipsoidal shape within the dominant pentacene thin-film phase and also further growth during storage. A faint topographical contrast as well as X-ray analysis corroborates our interpretation. As bulk-phase nucleation obstructs carrier percolation paths within the thin-film phase, hitherto uncontrolled structural inhomogeneity might have caused conflicting reports about pentacene carrier mobility. Infrared-spectroscopic nano-imaging of nanoscale polymorphism should have many applications ranging from organic nanocomposites to geologic minerals. PMID:24916130

Comparing the Efficacy of Three Different Nano-scale Bone Substitutes: In vivo Study

PubMed Central

Razavi, Sayed Mohammad; Rismanchian, Mansour; Jafari-pozve, Nasim; Nosouhian, Saied

2017-01-01

Background: Synthetic biocompatible bone substitutions have been used widely for bone tissue regeneration as they are safe and effective. The aim of this animal study is to compare the effectiveness of three different biocompatible bone substitutes, including nano-hydroxyapatite (nano-HA) nano-bioglass (nano-BG) and forstrite scaffolds. Materials and Methods: In this interventional and experimental study, four healthy dogs were anesthetized, and the first to fourth premolars were extracted in each quadrant. After healing, the linear incision on the crestal ridge from molar to anterior segment prepared in each quadrant and 16 defects in each dog were prepared. Nano-HA, nano-BG, and forstrite scaffold was prepared according to the size of defects and placed in the 12 defects randomly, four defects remained as a control group. The dogs were sacrificed in four time intervals (15, 30, 45, and 60 days after) and the percentage of different types of regenerated bones (lamellar and woven) and connective tissue were recorded in histological process. The data were analyzed using Mann–Whitney test (α = 0.05). Results: The difference in nano-HA and nano-BG with the control group was significant in three-time intervals regarding the amount of bone formation (P < 0.01). After 15 days, the nano-HA showed the highest amount of woven and lamellar bone regeneration (18.37 ± 1.06 and 30.44 ± 0.54). Conclusion: Nano-HA and nano-BG groups showed a significant amount of bone regeneration, especially after 30 days, but paying more surveys and observation to these materials as bone substitutes seem to be needed. PMID:28603705

Optical path of infrared neural stimulation in the guinea pig and cat cochlea

NASA Astrophysics Data System (ADS)

Rajguru, Suhrud M.; Hwang, Margaret; Moreno, Laura E.; Matic, Agnella I.; Stock, Stuart R.; Richter, Claus-Peter

2011-03-01

It has been demonstrated previously that infrared neural stimulation (INS) can be used to stimulate spiral ganglion cells in the cochlea. With INS, neural stimulation can be achieved without direct contact of the radiation source and the tissue and is spatially well resolved. The presence of fluids or bone between the target structure and the radiation source may lead to absorption or scattering of the radiation and limit the efficacy of INS. To develop INS based cochlear implants, it is critical to determine the beam path of the radiation in the cochlea. In the present study, we utilized noninvasive X-ray microtomography (microCT) to visualize the orientation and location of the optical fiber within the guinea pig and cat cochlea. Overall, the results indicated that the optical fiber was directed towards the spiral ganglion cells in the cochlea and not the nerve fibers in the center of the modiolus. The fiber was approximately 300 μm away from the target structures. In future studies, results from the microCT will be correlated with physiology obtained from recordings in the midbrain.

Spectral-optical-electrical-thermal properties of deposited thin films of nano-sized calcium(II)-8-hydroxy-5,7-dinitroquinolate complex.

PubMed

Farag, A A M; Haggag, Sawsan M S; Mahmoud, Mohamed E

2011-11-01

Spectral-optical-electrical-thermal properties of deposited thin films of nano-sized calcium(II)-8-hydroxy-5,7-dinitroquinolate complex, Ca[((NO(2))(2)-8HQ)(2)], were explored, studied and evaluated in this work. Thin films of Ca[((NO(2))(2)-8HQ)(2)] were assembled by using a direct, simple and efficient layer-by-layer (LBL) chemical deposition technique. The optical properties of thin films were investigated by using spectrophotometric measurements of transmittance and reflectance at normal incidence in the wavelength range 200-2500 nm. The refractive index, n, and the absorption index, k, of Ca[((NO(2))(2)-8HQ)(2)] films were determined from the measured transmittance and reflectance. The real and imaginary dielectric constants were also determined. The analysis of the spectral behavior of the absorption coefficient in the intrinsic absorption region reveals a direct allowed transition with band gaps of 1.1 eV and 2.4 eV for the optical and transport energy gaps, respectively. The current-voltage characteristics of Ca[((NO(2))(2)-8HQ)(2)] showed a trap-charge limited conduction in determining the current at the intermediate and high bias regimes. Graphical representation of the current-voltage characteristics yields three distinct linear parts indicating the existence of three conduction mechanisms. Structural characterization and identification were confirmed by using Fourier transform infrared spectroscopy (FT-IR). Scanning electron microscopy (SEM) was also used to image the surface morphology of the deposited nano-sized metal complex and such study revealed a high homogeneity in surface spherical particle distribution with average particles size in the range 20-40 nm. Thermal gravimetric analysis (TGA) was also studied for [(NO(2))(2)-8HQ] and Ca[((NO(2))(2)-8HQ)(2)] to evaluate and confirm the thermal stability characteristics incorporated into the synthesized nano-sized Ca[((NO(2))(2)-8HQ)(2)] complex. Copyright © 2011 Elsevier B.V. All rights reserved.

Characterization of preferential flow paths between boreholes in fractured rock using a nanoscale zero-valent iron tracer test

NASA Astrophysics Data System (ADS)

Chuang, Po-Yu; Chia, Yeeping; Liou, Ya-Hsuan; Teng, Mao-Hua; Liu, Ching-Yi; Lee, Tsai-Ping

2016-11-01

Recent advances in borehole geophysical techniques have improved characterization of cross-hole fracture flow. The direct detection of preferential flow paths in fractured rock, however, remains to be resolved. In this study, a novel approach using nanoscale zero-valent iron (nZVI or `nano-iron') as a tracer was developed for detecting fracture flow paths directly. Generally, only a few rock fractures are permeable while most are much less permeable. A heat-pulse flowmeter can be used to detect changes in flow velocity for delineating permeable fracture zones in the borehole and providing the design basis for the tracer test. When nano-iron particles are released in an injection well, they can migrate through the connecting permeable fracture and be attracted to a magnet array when arriving in an observation well. Such an attraction of incoming iron nanoparticles by the magnet can provide quantitative information for locating the position of the tracer inlet. A series of field experiments were conducted in two wells in fractured rock at a hydrogeological research station in Taiwan, to test the cross-hole migration of the nano-iron tracer through permeable connected fractures. The fluid conductivity recorded in the observation well confirmed the arrival of the injected nano-iron slurry. All of the iron nanoparticles attracted to the magnet array in the observation well were found at the depth of a permeable fracture zone delineated by the flowmeter. This study has demonstrated that integrating the nano-iron tracer test with flowmeter measurement has the potential to characterize preferential flow paths in fractured rock.