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Your search keyword '"Crowe, Devon G."' showing total 21 results
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21 results on '"Crowe, Devon G."'

2. Wave-front sensing by pseudo-phase-conjugate interferometry

Author

Baharav, Yael, Spektor, Boris, Shamir, Joseph, Crowe, Devon G., Rhodes, William, and Stroud, Robert

Subjects
Interferometry -- Research, Sensors -- Research, Astronomy, Physics
Abstract

A wave-front sensor based on pseudo-phase-conjugate interferometry is presented. We show that a pseudo-phase-conjugate interferometer is suitable for the measurement of phase distribution on a propagating wave. This new method may be employed for optical workshop applications and wave-front sensing for adaptive optics. The theoretical sensitivity of the interferometer is twice that of the Hartmann-Shack wave-front sensor. Preliminary laboratory experiments demonstrate excellent performance and consistency with computer simulations.

Published
1995

3. Improved compensation of atmospheric turbulence effects by multiple adaptive mirror systems

Author

Shamir, Joseph, Crowe, Devon G., and Beletic, James W.

Subjects
Diffraction -- Research, Atmospheric turbulence -- Research, Optics, Adaptive -- Research, Mirrors -- Usage, Astronomy, Physics
Abstract

Optical wave-front propagation in a layered model for the atmosphere is analyzed by the use of diffraction theory, leading to a novel approach for utilizing artificial guide stars. Considering recent observations of layering in the atmospheric turbulence, the results of this paper indicate that, even for very large telescopes, a substantial enlargement of the compensated angular field of view is possible when two adaptive mirrors and four or five artificial guide stars are employed. The required number of guide stars increases as the thickness of the turbulent layers increases, converging to the conventional results at the limit of continuously turbulent atmosphere.

Published
1993

4. Sidelobe reduction in optical signal processing

Author

Crowe, Devon G., Shamir, Joseph, and Ryan, Thomas W.

Subjects
Signal processing -- Research, Imaging systems -- Research, Astronomy, Physics
Abstract

A general procedure is introduced for sidelobe and noise reduction in optical or digital signal processing. Specific examples of sidelobe reduction in imaging are presented. It is demonstrated that the new method provides superior spatial resolution to previously proposed sidelobe-reduction techniques.

Published
1993

5. High-Powered CO2 Laser Interactions with Surfaces and Related Studies

Author

ARIZONA UNIV TUCSON OPTICAL SCIENCES CENTER, Crowe, Devon G., ARIZONA UNIV TUCSON OPTICAL SCIENCES CENTER, and Crowe, Devon G.

Abstract

Four Institutes in Russia were supported for the current year. Technical areas include high-temperature electronics with diamond-like carbon materials, laser resonance photoelectron and photoion microscopy, near-field laser microscopy, alteration of the optical properties of materials, atom lithography with laser light, tunable laser diode spectroscopy, remote sensing from space, and UV and X-Ray optics.

Published
1999

14. Characteristics of a chamber used for electrooptical device performance measurements in the presence of fog

Author

Cohen, D. K., Hunt, John H., and Crowe, Devon G.

Abstract

A fog chamber, developed to support measurement of the performance of electrooptical devices in the presence of fog, is discussed. Rationale for the fog chamber concept is presented. Emphasis is placed on the theory of operation of the chamber, an optical method for assessing fog particle characteristics, and the optical properties of the different types of fog produced.

Published
1982

15. Infrared propagation and performance modeling at the Electro-Optical Test Facility

Author

Crowe, Devon G., Cohen, D. K., and Dereniak, Eustace L.

Abstract

Fog spectral transmission data generated in the Electro-Optical Test Facility and propagation models used by the authors are presented. Preliminary results of a modeling effort are presented that support the following conclusions: (1) atmosphere emission is a major factor in IR system performance despite the fact it is commonly omitted; (2) the 3.5–4.1-μm interval offers superior performance to the 3–5 band at both relatively short and long ranges; and (3) the longer wavelength 9.5–11.5-μm band is superior to either the 3–5 or 3.5–4.1 bands in the presence of fog.

Published
1980

16. Electro-Optical Development System.

Author

SCIENCE APPLICATIONS INTERNATIONAL CORP TUCSON AZ, Crowe, Devon G, SCIENCE APPLICATIONS INTERNATIONAL CORP TUCSON AZ, and Crowe, Devon G

Abstract

This final report describes the successful delivery of all required items under the contract, as well as additional work not originally anticipated at the time the proposal was written. The original statement of work called for the development of an integrated system utilizing micro-channel plate (MCP) image intensification of a solid-state detector array with C-mount interface to a small diameter cystoscope. Five complete PAIR (Portal Aperture Image Refocusing) units were built and delivered. This task required devising a sophisticated optical design utilizing nine optical elements, in addition to a unique mechanical housing and coupling mechanism.

Published
1985

17. Surveillance Prototype, Interior Entry (SPIE) Project.

Author

SCIENCE APPLICATIONS INC TUCSON AZ, Crowe,Devon G, SCIENCE APPLICATIONS INC TUCSON AZ, and Crowe,Devon G

Abstract

A prototype SPIE device was delivered in a timely fashion in fulfillment of the contracted effort. Additional Army user agency support in a number of other areas was provided, as described in Section 2.0 and the Appendices. The needs of the Army user agency are still evolving and are not yet fully defined. SAI is prepared to continue the type of flexible support demonstrated under the present contract in future follow-on efforts. The SPIE device which has been delivered fully meets its design requirements and performs satisfactorily. The lightweight, portable, second-generation equipment proposed for the follow-on effort is anticipated to be capable of superior low-light level performance as well as compactness.

Published
1983

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