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Conference on current developments in Lens design and optical engineering VII

作者： Malone, Robert M. Becker, Steven A. Dolan, Daniel H. Hacking, Richard G. Hickman, Randy J. Kaufman, Morris I. Stevens, Gerald D. Turley, William D. NSTec Los Alamos Operat 182 East Gate Dr Los Alamos NM 87544 USA NSTec North Las Vegas Operat Las Vegas NV 89193 USA Sandia Natl Labs Albuquerque NM 87185 USA NSTec Special Technol Lab Santa Barbara CA 93111 USA

ISBN: (纸本)0819463671

Thermal imaging is an important, though challenging, diagnostic for shockwave experiments. Shock-compressed materials undergo transient temperature changes that cannot be recorded with standard (greater than ins response time) infrared detectors. A farther complication arises when optical elements near the experiment are destroyed. We have designed a thermal-imaging system for studying shock temperatures produced inside a gas gun at Sandia National Laboratories. Inexpensive, diamond-turned, parabolic mirrors relay an image of the shocked target to the exterior of the gas gun chamber through a sapphire vacuum port. The 3000-5000-nm portion of this image is directed to an infrared camera which acquires a snapshot of the target with a minimum exposure time of 150 us. A special mask is inserted at the last intermediate image plane, to provide dynamic thermal background recording during the event. Other wavelength bands of this image are split into high-speed detectors operating at 900-1700 nm and at 1700-3000 nm, for time-resolved pyrometry measurements. This system incorporates 90-degree, off-axis parabolic mirrors, which can collect low f/# light over a broad spectral range, for high-speed imaging. Matched mirror pairs must be used so that aberrations cancel. To eliminate image plane tilt, proper tip-to-tip orientation of the parabolic mirrors is required. If one parabolic mirror is rotated 180 degrees about the optical axis connecting the pair of parabolic mirrors, the resulting image is tilted by 60 degrees. Different focal-length mirrors cannot be used to magnify the image without substantially sacrificing image quality. This paper analyzes performance and aberrations of this imaging diagnostic.

关键词： mid-IR imaging off-axis parabolic mirrors gas gun imaging IR camera pyrometry

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2nd International Symposium on Advanced optical Manufacturing and Testing Technologies: Large Mirrors and Telescopes

2nd International Symposium on Advanced Optical Manufacturin...

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2nd International Symposium on Advanced optical Manufacturing and Testing Technologies: Large Mirrors and Telescopes

The proceedings contain 37 papers. The topics discussed include: current development of advanced optical technology in IOE, CAS;the mechatronic approach to the design of large mirrors and telescopes;new developments in the precessions process for manufacturing free-form, large-optical, and precision-mechanical surfaces;new solutions for innovative extremely large telescopes;test setup for large size deformable convex mirrors and application to 8m convex secondary mirrors for ELT's;support systems for segmented: an overview;application of steel balls to lens calibration in space solar telescope;CFRP solutions for the innovative telescope design;and properties of Zerodur mirron blanks for extremely large telescopes.

关键词： Telescopes

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Reduced risk of catastrophic optical mirror damage in high power tapered lasers using intra-cavity diverging lens

Reduced risk of catastrophic optical mirror damage in high p...

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Conference on Semiconductor Lasers and Laser Dynamics II

作者： Tee, Chyng Wen Lau, Fat Kit Zhao, Xin Penty, Richard White, Ian Calligaro, Michel Lecomte, Michel Parillaud, Olivier Michel, Nicolas Krakowski, Michel Univ Cambridge Dept Engn Trumpington St Cambridge CB2 1PZ England Alcatel Thales III V Lab F-91404 Orsay France

ISBN: (纸本)0819462403

This paper approaches the problem of catastrophic optical mirror damage from a geometrical waveguide point of view. Instead of engineering the characteristics of the semiconductor material at the facet of the laser using quantum-well intermixing or other sophisticated wafer growth technique, a simple intra-cavity diverging lens concept is proposed and demonstrated to be capable of effectively expanding the lateral optical mode in order to counter the effect of SHB and thermal lensing effect, thereby reducing the risk of COMD. The Gaussian output beam profile is maintained throughout the whole of the current range tested, showing that expanding the nearfield at facet using integrated lens does not compromise the brightness of the laser. A key finding in this work is that the diverging effect on an optical mode is a thoroughly scalable effect that can be engineered by varying the etch-depth of the integrated lens. Fabrication of the lens is compatible with existing laser manufacturing process flow in that it can be easily implemented either by post-processing technology or by an additional lithographical step. This opens up new possibility in device design, with the beam width along the lateral direction being a parameter that can be optimized in isolation.

关键词： high power laser high brightness laser tapered laser intra-cavity lens catastrophic optical mirror damage diffraction beam quality post-processing technology

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Composite end-fittings for lightweight telescope applications

Composite end-fittings for lightweight telescope application...

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38th SAMPE Fall Technical Conference: Global Advances in Materials and Process engineering

作者： Penado, F. Ernesto Broome, Scott T. Romeo, Robert C. Martin, Robert N. Clark iii, James H. Walton, Joshua A.P. Department of Mechanical Engineering Northern Arizona University Flagstaff AZ 86011 Composite Mirror Applications Inc. 1638 S. Research Loop Tucson AZ 85710 Naval Research Laboratory Navy Prototype Optical Interferometer Naval Observatory Flagstaff Station 10391 Observatory Road Flagstaff AZ 86001 Interferometrics Inc. Navy Prototype Optical Interferometer Naval Observatory Flagstaff Station 10391 Observatory Road Flagstaff AZ 86001

ISBN: (纸本)0938994727

Recent developments in lightweight, dimensionally stable, portable telescopes have required the application of advanced materials. For example, composite telescopes with 0.4- and 1.4- meter primary mirrors are currently being developed for use at the Naval Prototype optical Interferometer (NPOI). By fully utilizing composite construction for telescope elements such as optics, structure, mount, and end-fittings, the overall weight has been reduced nearly an order of magnitude over conventional designs. Furthermore, composite end-fittings reduce weight and increase stiffness at the secondary end of a telescope. Compared to their metallic counterparts, composite end-fittings contribute to reduced inertia, enhanced response, and improved performance. In this paper, details for the design and manufacturing procedure of a lightweight composite end-fitting for a telescope application are presented. The structural integrity of the end-fitting was verified by means of finite element analysis. It is shown that the use of composite materials provides significant weight savings over comparable end-fittings made of metal, in addition to a near zero coefficient of thermal expansion.

关键词： Telescopes

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InAs/InP quantum dot photonic crystal microcavities

InAs/InP quantum dot photonic crystal microcavities

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4th International Conference on Semiconductor Quantum Dots (QD 2006)

作者： Frederick, Simon Dalacu, Dan Poole, Philip J. Lapointe, Jean Aers, Geof C. Williams, Robin L. Natl Res Council Canada Inst Microstruct Sci Ottawa ON K1A 0R6 Canada Univ Ottawa Dept Phys Ottawa ON K1N 6N5 Canada

We examine the optical mode structure of two-dimensional, photonic crystal microcavities based on triple missing hole defects in hexagonal symmetry, etched air-hole, suspended InP membranes. Polarisation dependent photoluminescence from InAs/InP quantum dots embedded within the cavities is used to explore mode energies and quality factors, Q, as a function of cavity design parameters. Optimised Q values are in excess of 7,500 for the modified y-dipole mode. (c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

关键词： iii-V semiconductors

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Characterization of Novel iii-V Semiconductor Devices

Characterization of Novel III-V Semiconductor Devices

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作者： Sue Y. Young Massachusetts Institute of Technology

学位级别：硕士

This thesis presents the characterization of tunnel junctions and tunnel-junction-coupled lasers. The reverse-biased leakage current in a tunnel junction can be exploited to tunnel electrons from the valence band of one active region to the conduction band of a second active region. Thus, tunnel-junction-coupled lasers are highly efficient as they allow elec- trons to stimulate the emission of photons in more than one active region. The electrical characterization of InGaAs/GaAs tunnel junctions is presented. This thesis also gives an overview of the electrical and optical behavior of single-stage lasers as well as two-stage lasers coupled by InGaAs/GaAs tunnel junctions. Telecommunication applications moti- vated the use of InAs quantum dots and InAsP quantum dashes in the active layer design to provide near-infrared emission.

关键词： Electrical engineering and Computer Science.

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Roles of Bioelectronics for Quality of Life

Roles of Bioelectronics for Quality of Life

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European Conference on Solid-State Circuits (ESSCIRC)

作者： H. Schmidt A. Shakouri M. Isaacson S. M. Kang Baskin School of Engineering University of California Santa Cruz Santa Cruz CA USA

Bioelectronics is an important technology in enhancing the quality of life, especially for those who are suffering from physiological difficulties. Novel biomimetic microelectronic systems will enable treatment of some of presently incurable human handicaps such as hearing loss, blindness (retinal prosthesis), paralysis (neuron-muscular prosthesis), and memory loss (cortical prosthesis). With advancement of bionanotechnology and quantitative medical research, the potential application of biomimetic systems is highly promising. In this paper we review the current status of biomimetic microelectronic systems and challenging issues in basic interface between electrodes and neuronal network, laboratory on a chip (LoC), and generation of power for implantable devices. For laboratory-on-a-chip (LoC), we examine a new way of detecting and sensing molecules on a chip with single molecule/particle sensitivity by fusing integrated optics with microfluidics, based on integrated hollow-core antiresonant reflecting optical waveguides (ARROW) waveguides. With multilayer dielectric confinement, the light is guided through hollow channels with cross sections of a few microns squared. We have demonstrated efficient light guiding in liquid-core ARROWs, single-molecule fluorescence sensitivity in fully planar beam geometry, surface-enhanced Raman scattering, fluorescence from live ribosomes in buffer solution, and electrical fluorescence control by applying a voltage between fluidic reservoirs connected to the waveguide channels. For electrical power sourcing of implantable biomimetic devices and systems, we illustrate the potential of the diffusion potential differences established between two half-cells of electrolyte solutions of different concentrations to generate directly an electric current. This concentration cell operates solely on a salt concentration gradient. The future advancement of biomimetic systems design will critically depend on computer aids as in VLSI developments

关键词： Biomimetics Prosthetics optical waveguides Fluorescence Laboratories Lab-on-a-chip Power generation Integrated optics optical buffering optical waveguide components

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LWIR HgCdTe Focal Plane Array performance variations with epitaxial structure properties

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Proceedings of SPIE - The International Society for optical engineering 2006年 6395卷

作者： Chekanova, Galina V. Drugova, Albina A. Kholodnov, Viacheslav Kurbatov, Alexander V. Nikitin, Mikhail S. Federal State Unitary Enterprise ALPHA 2/46 Bld. 5 Plekhanova Str. Moscow 111123 Russia Institute of Radio Engineering and Electronics RAS 11 Mokhovaya Str. Moscow 125009 Russia

ISBN: (纸本)0819464937;9780819464934

Full replacement of scanning type thermal imaging (TI) equipment by starring type TI is on agenda of XXI century. Realization requires development and launching production of affordable large format high performance photovoltaic (PV) infrared (IR) focal plane arrays (FPA) covering spectral range from 1.3 to 14 μm. Advanced Infrared Focal Plane Arrays include Short-Wave (SWIR) 1.3-2.5 urn operating at near room temperature Top300 K, Mid-Wave (MWIR) 3-5.5 μm operating at higher temperatures (HOT) T op=200-240 K, extended Long-Wave (LWIR) 8-14 μm operating at temperatures Top=80-100 K and multi-color arrays. Challenge is serious and adequate research and development works have to be done. One of major approach is fabrication of megapixel IRFPA based on Hg 1-xCdxTe epitaxial multi-layer structures grown by molecular beam epitaxy (MBE). To be successful with approach it is necessary to optimize design of pixel and develop reproducible MBE growth technology issuing epitaxial structures with perfect layers and interfaces. Perhaps novel FPA will be based on photodiodes (PD) with p-n junction opposite to usually used n +-p junction. PD with optimal p-n junction could have lower dark current value than same size n+-p junction. It is desirable for proper multiplexing of PD arrays to Silicon Read-out Integrated Circuits (ROICs). Objective of the present work was to examine Hg1-xCd xTe LWIR PV FPA (λp ranged from 10 to 11 μm at Top=80-100 K) performance variation with doping level, absorber thickness, interface shunting and operating temperature.

关键词： Arrays

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Proceedings of SPIE: current developments in Lens design and optical engineering VI

Proceedings of SPIE: Current Developments in Lens Design and...

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current developments in Lens design and optical engineering VI

The proceedings contain 27 papers. The topics discussed include: using multi-function components to solve optical design challenges for DUV microlithographic applications;automated synthesis of both the topology and numerical parameters for seven patented optical lens systems using genetic programming;advances in lenticular lens arrays for visual display;wide field-of-view imaging system using a liquid crystal spatial light modulator;design tools for freeform optics;designing and specifying aspheres for manufacturability;infrared hybrid optics with high broadband efficiency;removing challenges in microlithographic optical design;laser beam filtering by refractive or diffractive microstructures;and a hybrid athermal CCD camera.

关键词： optical design

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High efficiency amorphous silicon superlattice solar cells

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WSEAS Transactions on Electronics 2006年第5期3卷 281-287页

作者： Varonides, Argyrios C. Department of Phsyics and Electrical Engineering University of Scranton Scranton PA 18510 United States

High efficiency solar cells seem to be the main direction of current research these days, in spite the high cost of fabrication. Production costs of highly effective solar cells are still very high, and thus amorphous silicon is still the only semiconductor material available for cheap and effective solar cells. On the other hand, amorphous silicon-based alloys have not been incorporated sufficiently by the industry, in spite the fact that they might provide advantages of more than one gap and wider optical window for incident wavelengths. Amorphous silicon/alloy superlattices provide advantages in solar cell design, such as (a) effective band-gap widening (b) effective mass separation (c) increased open-circuit voltage. The latter increases via Fermi level control, due to p-doping of potential barriers, pushing EF towards the valence bands, with simultaneous widening of the effective band gap, thus leading to potentially higher collection incident wavelengths. The density of gap states in the heavily doped layer is modeled as an exponential whose parameter kT* can be varied by the doping concentrations, while its activation energy saturates at some value. This communication provides (i) a general formulation of the problem at finite temperatures as well as numerical results for specific realizable contacts (ii) detailed treatment of gap states (iii) the neutrality condition (iv) a relation between Fermi level position and open-circuit voltage in the nitride region (superlattice p-region). For a p-(a-SiN: H/a-Si: H)-i (a-Si: H)-n (a-Si: H) sample, we compute the Fermi level position relative to the a-Si: H valence band edge. For low and wide gap thin layers of the order of 2.5 to 3.5 nm, open circuit voltage values are predicted in excess of 1.05 V, and efficiencies are predicted in excess of 12%.

关键词： Solar cells

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