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High-Power Diode Laser Technology and Applications Xii

作者： Pawlik, S. Todt, R. Moser, M. Romero, O. Lichtenstein, N. II-VI Laser Enterprise Binzstrasse 17 CH-8045 Zurich Switzerland

ISBN: (纸本)9780819498786

We report on our recent developments at ii-VI Laser Enterprise of laser diode sources for the 79x nm range. High power conversion efficiency in excess of 62% was demonstrated. For high power applications like Thulium fiber laser pumping we have achieved an output power of more than 12.5W in CW operation for 94 μm wide broad-area single-emitters. We added the functionality of wavelength stabilization to the laser diodes by using a distributed feedback grating (DFB). Locking has been obtained over the full current range between 1A and 4A tested so far with some margin for temperature variation. For efficient fiber laser pumping the laser diodes were integrated in a multi-emitter platform, achieving 38 W out of a 105 μm fiber within 0.15 NA. © 2014 SPIE.

关键词： Pumping (laser)

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Experimental and numerical study of counter-current flow in vertical pipe 12

Experimental and numerical study of counter-current flow in ...

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ASME 2014 12th Biennial Conference on engineering Systems design and Analysis, ESDA 2014

作者： Besagni, Giorgio Guédon, Gaël Inzoli, Fabio Politecnico di Milano Department of Energy Milan Italy

ISBN: (纸本)9780791845844

Counter current flow is encountered in a wide variety of industrial applications ranging from flows in nuclear reactors to process flows in chemical reactors. This paper describes experimental and numerical results obtained in a circular column of 240 mm inner diameter with two inner pipes. The counter current flow studied concerns an upward flow of air and a downward flow of water at ambient temperature and pressure. The following range of operating conditions is analyzed: superficial air velocities up to 0.25 m/s and superficial water velocities up to 0.04 m/s, corresponding to global void fractions up to 27.7%. The experimental investigations concerns (i) flow visualization, (ii) local data from a double optical probe and (iii) global void fraction data. Images obtained from an optical camera are used to observe the general flow pattern and to support the boundary conditions of the numerical simulations, in terms of average bubble diameter. Data obtained from the double optical probe are used to study local flow characteristics. The gas disengagement technique is used to obtain the global void fraction over a range of superficial air velocities for the validation of the numerical method. Numerical calculations are performed with an Eulerian two-fluid model using the commercial code ANSYS Fluent Release 14.5.7 and results are compared with experimental data. The effects of bubble diameter and various interfacial drag coefficients are studied. The formulation of the drag coefficient is found to have significant effects on the global void fraction predictions. However, using merely the drag law, numerical results are inaccurate. Copyright © 2014 by ASME.

关键词： Void fraction

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An analysis of electrical and optical characteristics of a type ii superlattice for optical switching applications

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Journal of Physics: Conference Series 2015年第1期619卷

作者： M Rahman A S M S Rouf F M Mohammedy Department of Electrical and Electronic Engineering Bangladesh University of Engineering and Technology Dhaka -1000 Bangladesh

The present work demonstrates an analysis of electronic and optical characteristics of InAs/GaSbType ii superlattice based photodetectors. The electronic characteristics are analyzed by developing a model of the Type ii superlattice. The 8 band k.p method is implemented to deduce the wavefunctions. The effects of temperature on zero-bias resistance- area product (R0A) are also included in the model. The newly proposed M-Structure design method is also implemented for our model. Electrical and optical properties of the material such as dark current density and absorption coefficient are calculated. At 50mV reverse bias, the dark current density is found equal to 1.5×10-4 A/cm2. These calculations are done based on the approximation based models of reflectivity. These results were used to demonstrate the variation of optical properties with applied bias voltage to be used as a novel optical switching technique in WDM based communication networks.

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current developments in Lens design and optical engineering XIV

Current Developments in Lens Design and Optical Engineering ...

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Conference on current developments in Lens design and optical engineering

ISBN: (纸本)9780819496911

The proceedings contain 37 papers. The topics discussed include: radiance limits of ceramic phosphors under high excitation fluxes;application of heterogeneous microlenses for solid state lighting;design of compact fisheye lens with slope-constrained Q-type aspheres;analytic formulas of the aspheric terms for convex-plano and plano-convex aspheric lenses;multi-core and GPU accelerated simulation of a radial star target imaged with equivalent T-number circular and Gaussian pupils;man versus machine: a lens design challenge;a 3D photographic capsule endoscope system with full field of view;double micro-prism array design for reducing dispersion on prism-based stereo camera system;optical architecture of the new generation infrared atmospheric sounder interferometer (IASI-NG);a three-channel miniaturized optical system for multi-resolution imaging;backward reflection analysis of transmitting channel of active laser ranging;and further results in measuring water ice buildup on optical components in cryogenic vacuum chambers.

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Materials science and design for germanium monolithic light source on silicon

Materials science and design for germanium monolithic light ...

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作者： Cai, Yan Massachusetts Institute of Technology

学位级别：博士

Germanium (Ge) is an optically active material with the advantages of Si-CMOS compatibility and monolithic integration. It has great potential to be used as the light emitter for Si photonics. Tensile strain and n-type doping are two key properties in Ge to achieve optical gain. This thesis mainly focuses on: (1) physical understandings of the threshold behavior of Ge-on-Si bulk laser and the temperature dependent performance; (2) process developments to grow and planarize the epitaxial Ge on Si in oxide trenches and corners; (3) introduction of n-type dopant into Ge-on-Si thin films while studying the threading dislocation behavior in n-Ge during annealing; (4) design an external cavity Ge laser integrated with Si waveguides for a low threshold current and single mode operation. Heavy n-type doping was observed to change the Ge electronic band structure by band gap narrowing effect. We also found a failure of using a simple Drude model to explain free carrier absorption in n-Ge. We modified the optical gain simulation based on the above two observations in Ge. We found a broad gain bandwidth of ~ 200 nm from 1550 nm to 1750 nm and a higher net materials gain. We predicted a theoretical lasing threshold current density of 5~10 kA/cm² in the bulk Ge laser device with the n-type doping of mid-10¹⁹ cm-³ at room temperature. We also predicted the Ge laser device would have better temperature stability regarding the threshold current compared to the iiI-V laser. Single crystalline Ge was epitaxial grown on Si in oxide trenches using ultra high vacuum chemical vapor deposition. The selective growth lead to the faceting in Ge because of the different growth rates of crystal orientations. We developed a suitable photolithography and oxide etch process to get the vertical oxide sidewall for Ge trench filling. We also tested the Ge growth in the T-shape corners to improve the reflectivity at the waveguide end. The T-shape structure was also useful for the Ge/Si waveguide coup

关键词： Materials Science and engineering

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NSLS-ii Biomedical Beamlines for Macromolecular Crystallography, FMX and AMX, and for X-ray Scattering, LIX: current developments

NSLS-II Biomedical Beamlines for Macromolecular Crystallogra...

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17th Pan-American Synchrotron Radiation Instrumentation Conference (SRI)

作者： Fuchs, M. R. Sweet, R. M. Berman, L. E. Hendrickson, W. A. Chubar, O. Canestrari, N. Idir, M. Yang, L. Schneider, D. K. Brookhaven Natl Lab Upton NY 11973 USA

We present the current status of development of the two macromolecular crystallography (MX) beamlines, FMX and AMX, and the X-ray scattering beamline LIX, at the National Synchrotron Light Source-ii (NSLS-ii) [1]. Together, FMX and AMX will cover a broad range of use cases from serial crystallography on micron sized crystals, to very large unit cell complexes, to rapid sample screening, e. g. for the always-hard-to-grow membrane proteins and for ligand binding studies. The LIX beamline will support a variety of X-ray scattering measurements for studies on proteins in solution, lipid membranes and biological tissues. We have performed Synchrotron Radiation Workshop (SRW) [2] and Shadow[3] simulations to help select optimal methods to modify the size of the beam easily and smoothly at both FMX and AMX. The very low emittance of the NSLS-ii storage ring and the resulting low divergence of the X-ray beam, as well as the long optical path lengths in the photon delivery systems lead to stringent requirements e. g. for vibrational stability and mirror quality. We discuss beamline design considerations addressing these challenges, such as combining mirror optics with compound refractive lenses (CRLs).

关键词： Synchrotron radiation

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Software-based design and fabrication of complex 3D shaped microparticles 18

Software-based design and fabrication of complex 3D shaped m...

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18th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2014

作者： Wu, C.-Y. Owsley, K. Chung, A.J. Di Carlo, D. Department of Bioengineering University of California Los Angeles United States TroyNY United States

ISBN: (纸本)9780979806476

Complex 3D microparticles could play an important role in several bioengineering technologies. However, the shape of particles that can currently be fabricated is restricted to certain types, like spheres, ellipsoids, and extrusions of 2D patterns. The design process for current technologies is also complicated for shapes other than 2D patterns. Here we demonstrate a fabrication method with software-enabled design to generate microparticles consisting of extrusions of two separately designed shapes, through (i) engineering the flow stream inside microchannels and (ii) exposing through arbitrary optical masks. We demonstrate agreement between fabricated particles and the software designs and an improved production rate. © 14CBMS.

关键词： Fabrication

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developments in Strategic Materials and Computational design V: A Collection of Papers Presented at the 38th International Conference on Advanced Ceramics and Composites January 27–31, 2014 Daytona Beach, Florida, Volume 35

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2014年

作者： Waltraud M. Kriven Dongming Zhu Kyoung ii Moon Taejin Hwang Jingyang Wang Charles Lewinsohn Yanchun Zhou

ISBN: (数字)9781119040293

ISBN: (纸本)9781119040286

This issue contains 31 papers from The American Ceramic Society’s 38th International Conference on Advanced Ceramics and Composites, held in Daytona Beach, Florida, January 26-31, 2014. This issue includes papers presented in the following Symposia and Focused Sessions: Symposium 2 – Advanced Ceramic Coatings for Structural, Environmental, and Functional Applications; Symposium 10 – Virtual Materials (Computational) design and Ceramic Genome; Symposium 11 – Advanced Materials and Innovative Processing Ideas for the Industrial Root Technology; Symposium 12 – Materials for Extreme Environments: Ultrahigh Temperature Ceramics and Nanolaminated Ternary Carbides and Nitrides; Focused Session 1 - Geopolymers and Chemically Bonded Ceramics; Focused Session 2 – Advanced Ceramic Materials and Processing for Photonics and Energy; Focused Session 3 – Rare Earth Oxides for Energy, optical and Biomedical Applications, Focused Session 4 – Ion-Transport Membranes; 3rd Global Pacific Rim engineering Ceramics Summit; and the 3rd Annual Global Young Investigator Forum

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Recent advancements in optofluidics-based single-cell analysis: optical on-chip cellular manipulation, treatment, and property detection

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LAB ON A CHIP 2014年第7期14卷 1230-1245页

作者： Huang, Nien-Tsu Zhang, Hua-li Chung, Meng-Ting Seo, Jung Hwan Kurabayashi, Katsuo Natl Taiwan Univ Dept Elect Engn Taipei 10617 Taiwan Natl Taiwan Univ Grad Inst Biomed Elect & Bioinformat Taipei 10617 Taiwan Nantong Univ Sch Mech Engn Nantong 226019 Peoples R China Univ So Calif Dept Biomed Engn Los Angeles CA 90007 USA Hongik Univ Dept Mech & Syst Design Engn Seoul 121791 South Korea Univ Michigan Dept Mech Engn Ann Arbor MI 48109 USA Univ Michigan Dept Elect Engn & Comp Sci Ann Arbor MI 48109 USA

Cellular analysis plays important roles in various biological applications, such as cell biology, drug development, and disease diagnosis. Conventional cellular analysis usually measures the average response from a whole cell group. However, bulk measurements may cause misleading interpretations due to cell heterogeneity. Another problem is that current cellular analysis may not be able to differentiate various subsets of cell populations, each exhibiting a different behavior than the others. Single-cell analysis techniques are developed to analyze cellular properties, conditions, or functional responses in a large cell population at the individual cell level. Integrating optics with microfluidic platforms provides a well-controlled microenvironment to precisely control single cell conditions and perform non-invasive high-throughput analysis. This paper reviews recent developments in optofluidic technologies for various optics-based single-cell analyses, which involve single cell manipulation, treatment, and property detection. Finally, we provide our views on the future development of integrated optics with microfluidics for single-cell analysis and discuss potential challenges and opportunities of this emerging research field in biological applications.

关键词： cell heterogeneity Cells Single-Cell Analysis Integrated optics Microfluidics system-on-chip Disease diagnosis cell population

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Enhancement of optical performance of near-UV nitride-based light emitting diodes with different aluminum composition barrier structure

Enhancement of optical performance of near-UV nitride-based ...

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作者： Wang, C.K. Chiou, Y.Z. Hsiang, C.C. Lee, D.H. Yan, W.Y. Chen, W.S. Cheng, C.M. Chen, K.H. Tang, J.J. Lee, J. Department of Electronic Engineering Southern Taiwan University of Science and Technology No. 1 Nan-Tai St. 71005 Tainan City Yung-Kang Dist. Taiwan R and D Center High Power Opto. Incorporation 40763 Taichung City Taiwan Department of Electronic Engineering and Computer Science Tung Fang Design University 82941 Kaohsiung City Taiwan

In this work, the InGaN/AlGaN multiple-quantum-well (MQW) near-ultraviolet (UV) light-emitting diodes (LEDs) with different aluminum compositions in the barrier layers are investigated and fabricated. The aluminum compositions of LED I, ii, and iiI are 0, 2.5, and 3.85%, respectively. The light output powers of LED I, ii, and iiI at an injection current of 350 mA are 95.46, 135.48 mW, and 179.54 mW, respectively. The light output power measured from LED iiI was 88% larger than that of LED I. The peak external quantum efficiency was enhanced from 9.24 to 17.26%. This result was attributed to the improvement of carrier confinement in the active region by using AlGaN-based barrier layers. The hot-cold effect of LEDs as functions of junction temperature currently is a very important key issue for actual application to LEDs. As the temperature increased, the injected carriers became excited and easily escaped from the active layer. Thus, the light output power of the LED decreased as the temperature increased. Compared with LED I and LED ii, the light output power of LED iiI with better carrier confinement was decreased more slowly with increasing temperature. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

关键词： Light emitting diodes

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