The Research Of The Beam Steering Of LN Anisotropic Acousto-optic Deflector

The beam steering theory is studied to solve the problem that we can not get wider 3db Bragg bandwidth and high diffraction efficiency at the same time in the optimum design of LN anisotropic acousto-optic deflector (AOD) which is a crucial issue in the process to design an AO deflector.Based upon the study of the unit cell structure of LN, the acoustic property and the optical property and the acousto-optic property are analyzed and presented. By solving the Christoffel Equation,the relationship between velocity and angles is obtained, and the ultrasonic inverse velocity curve is illustrated.The Dixon equations of AO diffraction on the XOZ and YOZ planes in LN crystal have been applied to obtain the geometric relationships of acousto-optic interaction.Therefore, the beam steering theory is proved to be a possible way to do the optimum design of LN anisotropic acousto-optic deflector. The detailed parameter data and the figures on the xoz and yoz planes with the angle of incidence of -5 degree are shown up, which will contribute to the desigh of AOD. And the parameter data and the figures have not been calculated ever.Compared with the performance curves of the primary AOD, the AOD with the optimum design shows great capacity: at the extreme point of Bragg Diffration the optimized one obtain a 2.4 times wilder relative 3db Bragg bandwidth than the primary one; and with the same relative 3db Bragg bandwidth which is 0.67, the optimized AOD has a relative 2 times of the the primary AOD.