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Optics

Air Force Institute of Technology

2001

Articles 1 - 6 of 6

Full-Text Articles in Physical Sciences and Mathematics

Modeling Axisymmetric Optical Precision Piezoelectric Membranes, James W. Rogers Jr. Oct 2001

Modeling Axisymmetric Optical Precision Piezoelectric Membranes, James W. Rogers Jr.

Theses and Dissertations

The US Department of Defense (DOD), as well as the National Aeronautics and Astronautics Administration (NASA) and the Jet Propulsion Laboratory (JPL) are interested in developing and deploying precise, compliant, light-weight, space-based structures. More specifically, the Air Force’s core competencies ‘Aerospace Superiority’ and ‘Information Superiority’ demand ever-increasing depth and breadth of capability. Whether used for energy transmission or optical reconnaissance, current launch restraints limit rigid space-based optical reflector size. To support this requirement, the Air Force Research Laboratory (AFRL) is developing a large space-based optical membrane telescope. Inflatable reflectors can conceptually break this barrier, but controlling such a compliant structure …

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Microcavity Surface Emitting Laser, Stewart Feld, John P. Loehr, James A. Lott Jul 2001

Microcavity Surface Emitting Laser, Stewart Feld, John P. Loehr, James A. Lott

AFIT Patents

A three-dimensional waveguiding structure for a microcavity surface-emitting laser is described in which native aluminum oxide layers provide control of intracavity waveguiding and the laser optical mode structure of the emitted beam. Microcavity lasers described herein account for the blueshift of the emission wavelength as the laser lateral dimensions are reduced to or below the emission wavelength.

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Control And Characterization Of Line-Addressable Micromirror Arrays, Harris J. Hall Mar 2001

Control And Characterization Of Line-Addressable Micromirror Arrays, Harris J. Hall

Theses and Dissertations

This research involved the design and implementation of a complete line-addressable control system for a 32x32 electrostatic piston-actuated micromirror array device. Line addressing reduces the number of control lines from N2 to 2N making it possible to design larger arrays and arrays with smaller element sizes. The system utilizes the electromechanical bi-stability of individual elements to bold arbitrary bi-stable phase patterns. The control system applies pulse width modulated (PWM) signals to the rows and columns of the micromirror array. Three modes of operation were conceived and built into the system. The first was the traditional signal scheme which requires …

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Photoluminescence Of Single Quantum Well Structures In Gallium Arsenide, Christian A. Bartholomew Mar 2001

Photoluminescence Of Single Quantum Well Structures In Gallium Arsenide, Christian A. Bartholomew

Theses and Dissertations

The continued development of state-of the-art semiconductor technologies and devices by the United States Air Force and the Department of Defense requires accurate and efficient techniques to evaluate and model these new materials. Of particular interest to the Air Force are quantum well structures which can be used for small-scale laser sources in fly-by-light applications, as efficient infrared countermeasures to heat-seeking missiles, or as advanced seekers in optically guided missiles. This thesis provides the initial experimental procedures and data necessary to begin producing accurate yet robust models. Although carrier effective masses could not be evaluated using hot-electron photoluminescence, photoluminescence excitation …

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Numerical Study Of Optical Delay In Semiconductor Multilayer Distributed Bragg Reflector And Tunable Microcavity Structures, Michael I. K. Etan Mar 2001

Numerical Study Of Optical Delay In Semiconductor Multilayer Distributed Bragg Reflector And Tunable Microcavity Structures, Michael I. K. Etan

Theses and Dissertations

The Air Force has a growing need for the greater bandwidth, speed, and flexibility offered by optical communication links. Future space systems and airborne platforms will most likely use optical signals for efficient power transmission and to minimize the possibility of spoofing and eavesdropping. Tunable optical delays play an important role in the implementation of free space optical communication links. The primary challenge in implementing these systems is the active maintenance of coherent wave fronts across the system's optical aperture. For space applications, this aperture may he hundreds of meters in diameter. Spatial segmentation of a large aperture into smaller …

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Incoherent Beam Combining Using Stimulated Brillouin Scattering In Multimode Fibers, Timothy H. Russell, Won B. Roh, John R. Marciante Feb 2001

Incoherent Beam Combining Using Stimulated Brillouin Scattering In Multimode Fibers, Timothy H. Russell, Won B. Roh, John R. Marciante

Faculty Publications

A beam combining technique for producing a single, spatially coherent beam from two mutually incoherent (temporally and spatially) lasers is demonstrated and the spatial coherence properties of the resulting beam are characterized. The technique is based on simultaneous excitation of stimulated Brillouin scattering by two independent lasers operating at two different wavelengths in a long multimode optical fiber. Though spectrally independent, the resulting Stokes beams produce essentially identical intensity distributions corresponding to the fundamental fiber mode. Abstract © 2001 Optical Society of America.

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