Replicated optics have been available since the 1950's. We recently undertook the development of 'supersmooth' (surface roughness &le 5 angstroms rms) replicated optics. This work has involved the repl...
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ISBN:
(纸本)0819409251
Replicated optics have been available since the 1950's. We recently undertook the development of 'supersmooth' (surface roughness &le 5 angstroms rms) replicated optics. This work has involved the replication of large optical flats. Measurements to determine the roughness of the surface have indicated that our process imparts an increase in surface roughness of less than 2 angstroms rms to a flat replica. We did not determine the absolute roughness of the surface but are able to show that the change in surface roughness was consistent between the two techniques used. current work involves the replication of spherical and off axis parabolics.
Advanced composites have been effectively used in space applications such as telescopes, optical benches, and metering structures. As the sophistication of optics and instrumentation increases, the need for near-zero ...
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ISBN:
(纸本)0819409251
Advanced composites have been effectively used in space applications such as telescopes, optical benches, and metering structures. As the sophistication of optics and instrumentation increases, the need for near-zero outgassing and extremely dimensionally stable composites becomes of paramount importance. Continuing improvements in resin and reinforcing fiber technology have resulted in a wider selection of materials for the composite designer of dimensionally stable structures. Additional improvements in metal sealing techniques promise unprecedented long-term environmental stability. These new options allow the designer to develop a dimensional stability strategy which conforms to design requirements and yields an optimum, cost-effective composite design approach. This paper addresses the major stability issues in composites and how stability can be predicted for long-term applications, along with design options to achieve program goals. Low-moisture-absorbing composites based on cyanate esters, metal sealing techniques, and long-range stability are also addressed.
The Center for Optics Manufacturing (COM) Process Science development program has advanced the current state of the art in optics manufacturing. Initial data indicates that the newly developed deterministic microgrind...
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ISBN:
(纸本)0819409251
The Center for Optics Manufacturing (COM) Process Science development program has advanced the current state of the art in optics manufacturing. Initial data indicates that the newly developed deterministic microgrinding process will generate specular optical surfaces. Deterministic microground surfaces, with 100 - 300 angstroms surface finishes, 1 - 2 microns of subsurface damage, and 1 wave peak-to-valley surface figure, have been produced on a range of glass types. Total cycle time, using a modified machine, took an average of five minutes per surface from start to finish. The high speeds, slow infeed rates, precision spindle, and computer control that were required to produce these microground surfaces could not have been achieved on current conventional equipment, thus emphasizing the importance of the Center's Process Science program.
The Center for Optics Manufacturing (COM), established in 1989 at the University of Rochester's Institute of Optics, is a strategic collaboration of the APOMA (American Precision Optics Manufacturers Association),...
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ISBN:
(纸本)0819409251
The Center for Optics Manufacturing (COM), established in 1989 at the University of Rochester's Institute of Optics, is a strategic collaboration of the APOMA (American Precision Optics Manufacturers Association), several academic institutions (Arizona, Central Florida, and Rochester), and the U.S. Army Material Command. This focused alliance is forging the optics industry's course for continuous improvement through novel manufacturing programs that provide the next generation technology, processes, and interactive training necessary to drive industry competitiveness to new levels.
Based on previous experience with air deployable fiber-optic systems, a ruggedized single- fiber cable has been developed to meet new requirements presented by such applications as robotics and radar remoting. Both mu...
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ISBN:
(纸本)0819408689
Based on previous experience with air deployable fiber-optic systems, a ruggedized single- fiber cable has been developed to meet new requirements presented by such applications as robotics and radar remoting. Both multimode and single-mode versions of the cable were developed. They are terminated with a militarized connector whose design built upon previous commercial developments. To minimize the size of the termination, an adaptation of the commercial STTM connector was inserted into a protective housing that provides mechanical and environmental performance stability dictated by system designers. In addition, the challenging requirement of hermaphrodicity was attained. Assemblies were fully tested in accordance with an approved test plan.
The construction of a very large optical telescopes can be prohibitively costly due to the massive weight of conventional primary mirrors. The cost of such telescopes can be reduced by the use of a segmented lightweig...
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ISBN:
(纸本)0819409251
The construction of a very large optical telescopes can be prohibitively costly due to the massive weight of conventional primary mirrors. The cost of such telescopes can be reduced by the use of a segmented lightweight primary mirror. An Itek process, computer controlled optical surfacing (CCOS), is ideally suited for manufacturing the off-axis aspheric segments. During CCOS operations, a subaperture tool is moved across the optic surface under accurate computer control. By altering the time that the machine grinds or polishes each surface region, accurate and rapid figure progress can be achieved. This CCOS technology is described including machine control, figuring process, pad-to-surface fit, vacuum grinding/polishing, and optic edge figuring. The utilization of CCOS to fabricate seven similar, thin, 2-meter, off- axis, aspheric optics and a lightweighted, active, off-axis mirror is related. Also, the paper summarizes the ongoing manufacture of a large active off-axis aspheric.
Control of an ion beam for milling optical surfaces is a nontrivial problem in two-dimensional deconvolution. The ion milling operation is performed by moving an ion beam gun through a grid of points over the surface ...
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ISBN:
(纸本)0819409251
Control of an ion beam for milling optical surfaces is a nontrivial problem in two-dimensional deconvolution. The ion milling operation is performed by moving an ion beam gun through a grid of points over the surface of an optical workpiece. The control problem is to determine the amount of time to dwell at each point in the grid to obtain a desired surface profile. This research treats the problem in linear algebra terms. The required dwell times are the solutions to a large, sparse system of linear equations. Traditional factorization methods such as Gaussian elimination cannot be used because the linear equations are severely ill conditioned. Theoretically, a least-squares solution to this problem exists. Practical approaches to finding a minimal least-squares solution are discussed.
Ion beam milling is an emerging advanced optical fabrication technology capable of deterministic figuring of optical surfaces. Much of the work in ion milling to data has emphasized figuring of glass-like materials, s...
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ISBN:
(纸本)0819409251
Ion beam milling is an emerging advanced optical fabrication technology capable of deterministic figuring of optical surfaces. Much of the work in ion milling to data has emphasized figuring of glass-like materials, such as fused silica, which do not significantly roughen during ion milling. However, for ion milling to reach its full potential as an advanced optical fabrication technique it must be applicable to a broad range of materials to interest in optical fabrication including polycrystalline metals, semiconductors, and ceramics. In order to assess the feasibility of ion milling, the effect of ion dose on roughness evolution was investigated for a variety of materials including: silicon, germanium, sapphire, silicon carbide, fused silica, aluminum, and copper. Single crystal silicon, germanium and sapphire as well as polycrystalline CVD silicon carbide did not significantly roughen during ion milling. The roughness evolution of aluminum, copper and gold thin films were also studied;fine grained gold films were found to remain smooth during ion milling.
By introducing strain into semiconductor lasers using GaAs/Ga(1-x)In(x)As quantum wells, their modulation bandwidth has been increased to beyond 20 GHz. Our approach to high modulation bandwidth strained layer quantum...
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ISBN:
(纸本)0819408689
By introducing strain into semiconductor lasers using GaAs/Ga(1-x)In(x)As quantum wells, their modulation bandwidth has been increased to beyond 20 GHz. Our approach to high modulation bandwidth strained layer quantum well lasers has been to fabricate short cavity (less than l00-micron) multiple quantum well (MQW) structures. In order to fabricate lasers of this length, the facets must be etched by chemically assisted ion beam etching (CAIBE) rather than cleaving. In such short cavity MQW lasers fabricated by CAIBE using two different layer structures, a 3-dB modulation bandwidth of 28 GHz is obtainable under CW conditions. The current study investigates (1) the growth of different quantum well and barrier materials and their effects on device performance, (2) the dependence of differential gain and damping on quantum well width, depth, and number, and (3) the relationship between threshold current and high speed performance. design criteria for optimizing high-speed performance are presented.
The proceedings contain 64 papers. The topic discussed include: present and future developments of high-power relativistic klystron amplifiers;design and initial operation of a repetitively pulsed high-current relativ...
The proceedings contain 64 papers. The topic discussed include: present and future developments of high-power relativistic klystron amplifiers;design and initial operation of a repetitively pulsed high-current relativistic klystron;fully self-consistent nonlinear theory of energy and current modulation in relativistic klystron amplifiers;critical reexamination of Pierce's space-charge factor (QC) in the conventional TWT theory;high-energy high-efficiency phase-locked HPM magnetron for an array;kinetic analysis of space-charge wave effects of a helical relativistic electron beam on the cyclotron maser instability;and coupling and scattering parameters of sinusoidal slow-wave structures that can be easily obtained from a state-variable analysis.
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