Research On The Optimum Design Of Anisotropic Acousto-Optic Device With Beam Steering Theory

We do systematical study on the optimum design of anisotropic acousto-optic deviceusing beam steering theory. The theories of the acousto-optic interaction and the beamsteering technology are introduced and the optical and acoustic properties of the LithiumNiobate (LinbO3) and Tellurium Dioxide (TeO2) crystals are systematically studied. Differentdesign methods are proposed in this paper for the optimum design of anisotropicacousto-optic device based on LinbO3and TeO2crystals, which are consisted of three parts:(1)Studies on the optimum design of LinbO3anisotropic acousto-optic device under differentacousto-optic operating modes.(2) The optimum design and characterization of anisotropicacousto-optic device with step-configurations (3) Optimum design of anisotropicacousto-optic device under the rotated acousto-optic plane.The acoustic properties of the LinbO3crystals in XOZ plane and YOZ plane are studiedby solving the Christopher equation and the reciprocal velocity curves of the ultrasonic wavesare systematically obtained by the numerical calculation. Beam steering theory combined withthe Dixon equations are employed to determine the optimum design parameters of the LinbO3device under different operating modes. The calculation results show that the centralfrequency of the acousto-optic device are determined by the angle of the incident light and thevelocity of the ultrasonic waves, where linear relationships also have been found between thecentral frequency and the velocity of the ultrasonic wave under the certain incident angle.The optimum design of LinbO3and TeO2acousto-optic device with step configurationtransducers are studied by the beam steering theory, respectively. The optimized resultsindicate that the utilization of the acoustic energies in3dB bandwidth can be dramaticallyimproved compared with device designed in plane configuration, while the central frequencyof the device is determined not only by the incident angle and the velocity of the ultrasonicwave, but also influenced by the number of transducers.We propose a new method for the optimum design of LinbO3acousto-optic device basedon the rotating of the operating plane, where the geometric relationships of the acousto-opticinteraction in the rotated plane are obtained through theoretical calculation and the optimumdesign under the condition of3dB bandwidth is realized. The calculation results show thatwith the increasing of the rotating angle, much longer transducer length as well as smallernumber of transducer pieces can be obtained under the octave condition. This is meaningfulfor the manufacture of acousto-optic device designed with multi-piece transducers, where thefewer piece of transducers and the longer transducer length lowers dramatically the difficultyfor the fabrication of acousto-optic device. This technique provides new concept for thedesign of anisotropic acousto-optic device with beam steering theory and shows potentialprospect in the applications of acousto-optic device.