Research On The Optimum Design Of Broadband Acousto-optic Deflector

Acousto-optical devices are functional devices that designed by acousto-optic effect, which are widely used in beam control, signal processing and optical communication. Based on the acousto-optic interaction theory, systematical studys on the optimized design of broadband anisotropic acousto-optic deflector with Lithium Niobate（LiNbO₃） and Tellurium Dioxide（TeO₂） crystals are carried out. There are three parts in the paper: Research on the broadband operating mode of anisotropic acousto-optic deflector（AOD） using tellurium dioxide crystal; The optimized design of anomalous acousto-optic deflector based on the rotating of acousto-optic operation plane; The beam steering characteristics of anisotropic acousto-optic device with step-configuration transducers.Theoretical studies on the broadband operating mode of anisotropic AOD using TeO₂ crystal are carried out. The Dixon equation that characterizes the geometrical relationships of the acousto-optic interaction is obtained based on the acousto-optic properties of TeO₂ crystal. The bandwidth and the central frequency properties under ±1 order diffraction are systematically studied in the TOZ plane, the design parameters under different off-axis angle are also obtained.The broadband design of Lithium Niobate AOD are carried out based on the rotation of the acousto-optic operating plane, two differenrt types of AOD that named off-axis AOD and along-axis AOD are studied systimatically. The rotating of the operation plane results in the separation of refractive surface on the direction of Z axis, which helps to realize the broadband design of LiNbO₃ AOD. Based on the analysis of the curves of incident angle and diffractive angle with respect to frenquency of the ultrasonic, the properties of the central frequency and the bandwidth with respect to the rotation angle and the veloctiy of the ultrasonic are sysmatically studied and the design parameters are also obtained, which provides theretical reference on the broadband design of Lithium Niobate AOD.The optimized design of LiNbO₃ anomalous AOD with beam steering theory are carried out. A new method is proposed for the design of AOD with step-configuration transducers. The 3 dB curves under different operating modes are sysmatically obtained. The properties of the central frequency and the bandwidth with respect to the incident angle and the veloctiy of the ultrasonic are sysmatically analyzed. The research results can be referenced for the AOD designed with beam steering theory.