Holographic Correction of Aberrations in Optical Systems Employing Synthetic Apertures.
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
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The effectiveness of using holograms to correct aberrated wavefronts exiting a misaligned synthetic aperture is investigated. Negative transparency, photographic plate holograms were used as corrector plates for eliminating aberrations in a three lens synthetic aperture system built from commercially available components. In addition, holograms created within a lithium niobate crystal in near real time less than 112 hours were used to correct aberrations in a misaligned single lens system. The effectiveness of each aberration correction was qualitatively evaluated by comparing the impulse response of an unaberrated, aligned system to the impulse response of the corrected, misaligned system. These evaluations were made by comparing photographs of the corrected impulse response to computer generated plots of the unaberrated response predicted by Fourier optics. The holographic corrections made to the synthetic aperture were found to transform an aberrated impulse response into one that did resemble the computer prediction. However, the diffraction efficiency of the correction hologram was very low, and the impulse response obtained from it was very dim.