Image aberrations caused by light diffraction via ultrasonic waves in uniaxial crystals

Abstract

The problem of optical image deformations caused by the phenomenon of light beam diffraction in uniaxial crystals by ultrasonic waves is considered in the paper. A general analytical expression is derived describing a dependence of spatial deformations and transmission coefficients on incidence angles as well as on parameters of the crystal and the ultrasound. The most interesting wide-angle diffraction configurations are analyzed, and all types of spatial distortions and transfer functions are described.

Определение Аберрационных Характеристик Оптических Систем, Содержащих Акустооптические Дифракционные Элементы

“…Формулы (2) позволяют определить в общем случае вид и величину пространственных искажений при АО-дифракции, но представление их в виде общепринятых аберрационных характери-стик ОС трудоемко. Ранее предпринимались попытки определения аберраций АО-элементов путем анализа аналитической зависимости ψ i (θ 1 , θ 2 ), но они основывались лишь на разложении этих зависимостей в ряд по малым параметрам θ 1 = θ 1 − θ s 1 , θ 2 = θ 2 − θ s 2 , представля-ющим собой отклонения направления распространения световой волны от центрального направления θ s 1 , θ s 2 падающего пучка света [10][11][12]. Та-ким образом, при проектировании АО-приборов до настоящего времени удавалось рассмотреть лишь отдельные типы искажений, вызываемые дифракцией света на звуковой волне, а величина искажений оценивалась лишь приближенно.…”

Double-AOTF-based aberration-free spectral imaging endoscopic system for biomedical applications

“…e. Double monochromatization signi¯cantly increases the contrast 12 and the quality of the transmitted image 13 in the whole spectral range. While each AO cell causes image deformations, 10 in the developed tandem double-AOTF, linear and nonlinear distortion aberrations are almost completely compensated. 13 Monochromator was designed and assembled as a separate PC-controlled device for image spectral ltration [see Fig.…”

“…8 Most of AOTF-based spectral imagers for endoscopic photoluminescence analysis utilize single acousto-optic (AO) cell, which lacks spectral drift and chromatic aberrations of di®racted image. 10 That is why for spectral images matching, an additional correction procedure must be applied that complicates the analysis and makes it time-consuming and less reliable. 11 Another problem concerns the optical coupling between the endoscope ocular and the AOTF entrance pupil.…”

Recent Advances in Acousto-Optic Instrumentation for Astronomy

“…Without special care of the problem, that type of aberrations results in defocusing of the image while tuning the transmitted optical wavelength [11]. Accurate analysis of interaction geometry in AOTFs shows that image distortions take place during anisotropic Bragg diraction [12]. In this paper, our attention is focused on a dierent type of aberrations in AOTF-based imaging spectrometers that was not studied before, namely on astigmatism.…”