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8th Conference on current developments in optical design and optical engineering

作者： Alexander, CD Swift, W Ghosh, K Ramsey, B NASA George C Marshall Space Flight Ctr Dept Space Sci Huntsville AL 35812 USA

ISBN: (纸本)0819432652

This paper describes the design of a camera system capable of acquiring stars during both the day and night cycles of a high altitude balloon flight (35-42 km). The camera system will be filtered to operate in the R and I bands (similar to 600-1000nm), and simulations have been run using MODTRAN atmospheric code to determine the worse case sky brightness at 35km. With a worse case daytime sky brightness of 2x10(-5) W/cm(2)/sr/mu m at 600nm, the sensitivity of the camera system will allow acquisition of at least 1-2 stars/degrees(2) at star magnitude limits of 7.8-8.1. The system will have an F2.8, 64.3mm diameter lens and a 1340 x 1037 CCD digitized to 12 bits. The CCD is comprised of 6.8 mu m x 6.8 mu m pixels with a well depth of 45,000 electrons and quantum efficiency of 0.54 at 700nm. The camera's field-of-view will be 6.33 degrees(2) and provide attitude knowledge to 8 arcsec or better. A test flight of the system is scheduled for fall 1999.

关键词： star camera aspect system stratospheric balloon flights daytime star camera R band

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Spatio-temporal structures of laser-induced anisotropy and applications

Spatio-temporal structures of laser-induced anisotropy and a...

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8th Conference on current developments in optical design and optical engineering

作者： Chen, X Berger, H Chaux, R Univ Bourgogne Phys Lab F-21078 Dijon France

ISBN: (纸本)0819432652

We report new observations of optical spatio-temporal structures formed in a naturally isotropic solid-state material. The phenomenon is due to laser-induced anisotropy. In fact, a part of the optical power is absorbed by the material which leads to the sample heating, the refractive index of the medium becomes laser power dependent under strong beam intensity excitation. This refractive index variation modifies in turn the optical polarization of the beam. As a consequence a polarization pattern is induced. If the material is placed near the laser beam focus, usually the induced depolarization is strong due to the high beam intensity. We observed however, that the induced depolarization is reduced sharply near the focus. This phenomenon was not observed up to now. We have developed a model which shows that both the index variations in transverse and longitudinal directions contribute to the phase shift, and are responsible for the depolarization As a result, the competition between these two contributions plays a key role in the polarization changes near focus. Our observation is accounted for by a transient nonlinear refractive index model. Good agreement with the theoretical description of the pattern formation is obtained. We found that in some appropriated experimental configurations, these spatio-temporal structures present advantages in the applications, e.g. in conceiving a two dimensional vectorial optical sensor.

关键词： optical pattern application spatio-temporal structure anisotropy

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QuickBird telescope: The reality of large, high-quality, commercial space optics

QuickBird telescope: The reality of large, high-quality, com...

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Proceedings of the 1999 current developments in optical design and optical engineering ViiI

作者： Figoski, John W. Ball Aerospace & Technologies Corp Boulder CO United States

The QuickBird telescope represents a significant accomplishment as the first large-aperture, high-resolution, totally unobscured optical system developed as a fixed-price commercial product. The telescope was aligned and tested in a dedicated facility at Ball Aerospace & Technologies Corp. specifically developed to reduce the total process time of building and testing complex optical systems. This presentation summarizes design features, mirror-manufacturing results, telescope alignment, and test results. The telescope has a 60 cm aperture, three off-axis conic mirrors and a fold. It delivers near-diffraction-limited performance over a 33.7 cm long image surface. The design is a re-imaging, three-mirror anastigmat. The mirrors are mounted to a graphite-epoxy laminate optical bench via low-distortion, kinematic mounts. The four mirrors were aligned and produce a measured wavefront error of 0.04 waves rms at λ = 0.6328 μm. The effective focal length was measured to better than 0.01% across the field of view and MTF was measured using wavefront, point-source, and sine-pattern techniques.

关键词： optical telescopes

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optical design of ARIES: the new near infrared science instrument for the adaptive f/15 Multiple Mirror Telescope

Optical design of ARIES: the new near infrared science instr...

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8th Conference on current developments in optical design and optical engineering

作者： Sarlot, RJ McCarthy, DW Burge, JH Ge, J Univ Arizona Steward Observ Tucson AZ 85721 USA

ISBN: (纸本)0819432652

Steward Observatory is building a deformable f/15 secondary mirror that will compensate for atmospheric turbulence for the 6.5 m Multiple Mirror Telescope conversion. With the proposed adaptive optics system, this new telescope is expected to resolve diffraction limited images (greater than 80% Strehl ratio at 2.2 mu m), approximately an order of magnitude better than present seeing. This improved visibility with a larger fight collecting area and low thermal background requires a new science instrument, diffraction limited for the 1 to 5 mu m region. This science instrument, presently in its early manufacturing stages, consists of four cameras (optimized for plate scales from 0.019 arcsec/pixel to 0.102 arcsec/pixel), low resolution spectroscopy with grisms (lambda/Delta lambda from 250 to 500), high resolution spectroscopy with a cross-dispersed Echelle grating (lambda/Delta lambda from 3,000 to 60,000) and an atmospheric dispersion corrector. The cameras will provide simultaneous slit viewing, differential imaging and two pixel sampling over the full wavelength band. Each camera will operate with a 1024x1024 HgCdTe array optimized for the spectral region of the camera. An infrared tip/tilt sensor is also incorporated into the instrument that will relay natural guide star motion to the adaptive secondary in a closed-loop approach. This paper is an optical design instrument overview.

关键词： adaptive optics infrared camera spectrograph atmospheric dispersion corrector MMT

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optical microscope for nuclear emulsion readout -: system design and results in application

Optical microscope for nuclear emulsion readout -: system de...

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8th Conference on current developments in optical design and optical engineering

作者： Winkler, K Körner, L Gussek, P Balogh, I Breitfelder, S Schlichting, J Dupraz, JP Fabre, JP Panman, J Papadopoulos, IM Zucchelli, P Van de Vyver, B Syst GmbH Opt JENOPTIK Laser Jena Germany

ISBN: (纸本)0819432652

Experiments such as CHORUS at CERN require the inspection of a large amount of nuclear emulsion plates exposed to particle beams. Rare events need to be found, measured and analysed. Their features are stored as grains in microscopic dimensions in a three-dimensional stack of plates. A new, fully automatic immersion microscope system was developed for this purpose. It features high resolution, small depth of focus, large working distance, large field of view and synchronization of illumination and detector. An additional requirement is given by variations in the refraction index and in the relative thickness of immersion oil and emulsion. The approach used here is an imaging system based on a vario objective lens (variable oil immersion) with extreme numerical aperture, large working distance and wide field, combined with a matched high-aperture Koehler illuminator. The light source is a mercury are lamp, combined with a filter package for the g-line. It includes liquid crystal elements for synchronized shuttering and variable attenuation. The theoretical resolution is less than 1 micron in x, y, z within a volume of 0.5mm diameter (x, y) times 1 mm scanning depth (z) in all situations within a predefined index range (1.49 to 1.54). Three identical pieces of the system have been built. The experimentally measured resolution confirms the expectations and is better than 1 micron in all three dimensions. This is the result of a complex process of system design and manufacturing, unifying optical, opto-mechanical and optoelectronical contributions. This process spans from the early stages of feasibility and manufacturing up to the test and adjustment procedures. The three prototypes are operational since the fall of 1998 in the frame of the CHORUS project. Practical experience and application results are presented.

关键词： optical microscopy oil immersion nuclear emulsion readout variable immersion systems design

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Image quality criteria for wide-field X-ray imaging applications

Image quality criteria for wide-field X-ray imaging applicat...

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Proceedings of the 1999 current developments in optical design and optical engineering ViiI

作者： Thompson, Patrick L. Harvey, James E. Univ of Central Florida Orlando FL United States

For staring, wide-field applications, such as a solar X-ray imager, the severe off-axis aberrations of the classical Wolter Type-I grazing incidence X-ray telescope design drastically limits the `resolution' near the solar limb. A specification upon on-axis fractional encircled energy is thus not an appropriate image quality criterion for such wide-angle applications. A more meaningful image quality criterion would be a field-weighted-average measure of `resolution'. Since surface scattering effects from residual optical fabrication errors are always substantial at these very short wavelengths, the field-weighted-average half-power radius is a far more appropriate measure of aerial resolution. If an ideal mosaic detector array is being used in the focal plane, the finite pixel size provides a practical limit to this system performance. Thus, the total number of aerial resolution elements enclosed by the operational field-of-view, expressed as a percentage of the number of ideal detector pixels, is a further improved image quality criterion. In this paper we describe the development of an image quality criterion for wide-field applications of grazing incidence X-ray telescopes which leads to a new class of grazing incidence designs described in a following companion paper.

关键词： optical systems

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Capabilities of an arch element for correcting conformal optical domes

Capabilities of an arch element for correcting conformal opt...

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Proceedings of the 1999 current developments in optical design and optical engineering ViiI

作者： Sparrold, Scott W. Knapp, David J. Manhart, Paul K. Elsberry, Kevin W. Raytheon Missile Systems Tucson United States

This paper presents an approach for correcting conformal missile domes with a non-rotationally symmetric optical element called an arch. A parametric study in terms of aerodynamics, fineness ratio, maximum seeker look angle and dome index of refraction will demonstrate its capabilities for correcting conformal domes. A nomograph for trading optical performance versus relative missile range will also be presented.

关键词： optical systems

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Recent developments in hybrid mirror technology for the Next Generation Space Telescope

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Proceedings of SPIE - The International Society for optical engineering 1999年 3749卷 82-83页

作者： Dodson, Kelly J. Mehle, Greg V. Kasl, Eldon P. Composite Optics Inc San Diego United States

The objective of this paper is to report the recent developments in lightweight mirror technology at Composite Optics, Incorporated (COI). The developments are a result of the activities being conducted in support of the Next Generation Space Telescope (NGST) Program. The sponsors of these efforts are the NASA Marshall and Goddard Space Flight Centers. The requirements, design approach, performance, and the technology status for the program are summarized. The emergence of composite materials provides exciting potential for nontraditional, accurate, lightweight, stable, stiff, and high strength mirrors. This evolving technology promises significant improvement in reducing weight, cost and cycle time for future infrared, visible, and x-ray systems. Customers currently embracing composite mirror technology for radiometric use are already reaping substantial system performance benefits. Other customers interested in LIDAR, IR, visible, and grazing incidence x-ray applications are eagerly awaiting successful completion of current technology development and demonstration efforts.

关键词： Mirrors

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Computer modeling and analysis of veiling glare and stray light in Fresnel lens optical systems

Computer modeling and analysis of veiling glare and stray li...

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Proceedings of the 1999 current developments in optical design and optical engineering ViiI

作者： Lamb, David J. Hillman, Lloyd W. Univ of Alabama in Huntsville Huntsville United States

Veiling glare (or flare) occurs in an imaging system when non-image forming flux strikes the focal surface. This light tends to reduce image contrast and can be caused by surface defects, dust, or anything else that might cause light to deviate from its intended imaging path. Fresnel lenses contain many such non-image forming structures as a result of their faceted and discontinuous nature. Sample optical systems for an extensive air shower observatory have been designed that consist of multiple Fresnel lenses. Veiling glare is expected to be significant in these systems, and it is desired to quantify its extent and ramifications. To this end, a series of tests has been performed on the Fresnel lens systems using non-imaging optical analysis software. A method for obtaining veiling glare information efficiently has been developed based upon the manner in which it is measured in real optical systems. By using computer software, the effects that several different parameters have on the veiling glare are analyzed independently without the use of expensive prototypes. It is shown that the amount of veiling glare is highly dependent upon the system configuration and that generalized conclusions regarding veiling glare and the number of Fresnel surfaces in a system are not possible. The analysis methods developed here, however, can be used to efficiently analyze the stray light in any system.

关键词： optical instrument lenses

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High speed optical shutter coupled to fast readout CCD camera

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Proceedings of SPIE - The International Society for optical engineering 1999年 3649卷 22-30页

作者： Yates, George J. Pena, Claudine R. McDonald Jr., Thomas E. Gallegos, Robert A. Numkena, Dustin Turko, Bojan T. Ziska, George Millaud, Jacques Diaz, Rick Buckley, John Anthony, Glen Araki, Takae Larson, Eric Los Alamos Natl Lab

A high frame rate optically shuttered CCD camera for radiometric imaging of transient optical phenomena has been designed and several prototypes fabricated, which are now in evaluation phase. The camera design incorporates stripline geometry image intensifiers for ultra fast image shutters capable of 200ps exposures. The intensifiers are fiber optically coupled to a multiport CCD capable of 75MHz pixel clocking to achieve 4KHz frame rate for 512 × 512 pixels from simultaneous readout of 16 individual segments of the CCD array. The intensifier, Philips XX1412MH/EO3, is generically a Generation ii proximity-focused micro channel plate intensifier (MCPii) redesigned for high speed gating by Los Alamos National Laboratory and manufactured by Philips Components. The CCD is a Reticon HS0512J split storage with bi-directional vertical readout architecture. The camera mainframe is designed utilizing a multilayer motherboard for transporting CCD video signals and clocks via imbedded stripline buses designed for 100MHz operation. The MCPii gate duration and gain variables are controlled and measured in real time and up-dated for data logging each frame, with 10-bit resolution, selectable either locally or by computer. The camera provides both analog and 10-bit digital video. The camera's architecture, salient design characteristics, and current test data depicting resolution, dynamic range, shutter sequences, and image reconstruction will be presented and discussed.

关键词： High speed cameras

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