Studies On The Optimized Design Of LiNbO3 Anisotropic Acousto-optic Deflector Based On Ultrasonic Beam Steering Under Different Frequency Bands

The acousto-optic effect is defined as the diffraction of the incident light by the periodic distribution of the refractive index of the medium,which is caused by the propagation of the ultrasonic in the crystal.Acousto-optic devices have been widely applied in many fields,such as beam control,optical signal processing,optical computing and optical communication.The bandwidth and diffractive efficiency are the two important design parameters of the acousto-optic device,whereas the contradiction between them is irreconcilable for acousto-optic device designed with single-piece transducer.By utilizing the beam steering theory,the acousto-optic device based on multi-transducers can achieve a higher diffraction efficiency and wider bandwidth simultaneously,thus the performance of the device can be improved effectively.The optimization design of acousto-optic deflectors in different frequency bands is systematically studied in this paper,which includes three parts:The research background and applications of acousto-optic technology are summarized,the coupling wave equation and the principle of the beam steering theory are given as the theoretical foundation for the optimization design of acousto-optic devices.The optimization design of acousto-optic deflectors with plane-configuration transducers under different frequency bands is studied systematically.The design parameters under the3 d B condition are obtained and the relationships of the bandwidth,the central frequency and the transducer length with respect to the incident angle and the number of the transducers are also obtained by numerical simulation.The results show that the optimum design can be realized under the condition of N=16 and the contradiction between the bandwidth and the diffraction efficiency can be effectively solved.A new optimization method is proposed for the optimization design of acousto-optic deflectors with step-configuration transducers,the design parameters are obtained and the numerical fittings under different frequency bands are also carried out.Compared with the plane configuration,acousto-optic devices with step-configuration achieve higher energy utilization as well as higher diffractive efficiency due to the longer length of the transducers,therefore the performance of the acousto-optic device can be improved...