A theoretical and experimental study has been made of planar acousto-optic light deflectors with particular emphasis on acoustic beam steering as a means of improving device performance. The theoretical model takes into account the electrical drive characteristics of beam-steered interdigital surface acoustic wave (SAW) transducers, anisotropic diffraction of acoustic waves and the rigorous theory of the interaction between guided optical waves and high frequency surface acoustic waves. The experiments were carried out on nickel indiffused waveguides on Y-cut LiNbO₃ substrates. A four-section, three finger pair transducer array was used to launch acoustic waves with propagation direction centered at 21.8° from the Z axis. A center frequency of 200 MHz was chosen as a compromise between high acousto-optic bandwidth and ease of fabrication. The deflector had a bandwidth of more than 60 MHz and gave 44 resolvable spots with an optical wave 2.5 mm wide. The observed frequency response of the diffraction efficiency was in excellent agreement with the theory. It was concluded that beam steering is an advantageous technique for devices requiring large bandwidth and high diffraction efficiency. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

by Changsong Qin. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1997. / Includes bibliographical references (p. 128-139). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web.

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Thesis (M.S.)--Rochester Institute of Technology, 1993. / Typescript. Includes bibliographical references (leaves 152-153).

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v, 137 p. : ill., plates ; 26 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Physics, 1974

Thesis (Ph.D.) -- University of Adelaide, Dept. of Physics, 1974.

The performance of two acoustooptical systems for ultrasonic materials characterization has been investigated. The first system uses an optical fiber interferometric technique to detect directly slowly varying residual stresses and both high frequency continuous and transient ultrasonic waves characteristic of acoustic emission events in composites. The potential for embedding optical fibers inside fiber composites during manufacturing makes this an attractive built-in alternative to conventional contact transducers for the nondestructive evaluation of composite materials. Experimental static and dynamic calibration as well as the frequency domain characterization of acoustic emission as detected by this system are discussed. The second system is a pulse-echo transducer system that generates an electronically focusable ultrasonic field and detects the reflected field optically. The generating transducer consists of concentric ring electrodes etched on a single x-cut quartz crystal substrate with a 1 mm circular aperture at the center. By shaping the amplitude and phase profile of the high voltage pulse applied to each ring, a focused ultrasonic field results at an adjustable distance below the transducer. If the field is focused below the surface of a specimen, energy in the wave reflected from the focal point modulates the normal and parallel components of surface displacement. Furthermore, if the sample arm of an adaptively stabilized interferometer is focused on the free surface at the transducer center aperture, the normal component of surface motion may be detected. This system has potential applications in materials characterization and evaluation as well as biomedical imaging. The design of the system is discussed with particular emphasis on the necessary sub-system interfaces required for operational flexibility. / Master of Science

Acousto-optic hybrid bistable devices have been studied previously. However, previous studies are limited only to the first-Bragg regime involving two diffracted orders. No actual comparison has been made between experimental results and theoretical predictions. A model including both acousto-optic diffraction and a nonlinear feedback path is studied in this thesis. Theoretical results based on diffraction involving two and four diffracted orders have been obtained and compared. Experimental results confirm the validity of the theoretical model. The principle of operation is discussed along with experimental results. The performance of the bistable system is then studied. In the investigation, the Klein-Cook parameter, Q, has been introduced into the study. Methods to improve the performance of the system with a low Q acousto-optic device by adjusting the effective feedback gain and the operation point are suggested. Finally, a technique to measure the effective feedback gain has been derived. Future topics are suggested along with a modified and improved model. / Master of Science