TeO_2超声跟踪反常声光偏转器的优化设计  

Optimal Design of TeO_2 Ultrasonic Beam-steering Anisotropic Acousto-optic Deflector

作　　者：俞宽新[1] 米银梅[1] 索萌[1] 

机构地区：[1]北京工业大学应用数理学院,北京100022

出　　处：《压电与声光》2007年第5期510-512,529,共4页Piezoelectrics & Acoustooptics

基　　金：国家自然科学基金资助项目(60077017)

摘　　要：建立起TeO2晶体在tz平面内o→e模式的Dixon方程,并求解得到适合超声跟踪所需要的声离轴角-频率(aθ-f)曲线。提出了一种新的反常声光偏转器超声跟踪优化设计方法,在保证频带均匀性的基础上,尽量扩大带宽,并使用该方法对TeO2反常声光偏转器进行了优化设计。将跟踪与非跟踪的设计结果进行了分析对比:当两者都达到倍频程相对带宽时,跟踪比非跟踪的相对长度增加了34.7%;当两者都满足进入布喇格区条件时,跟踪比非跟踪的相对带宽提高了9.1%。说明超声跟踪可缓解带宽与衍射效率、带宽与进入布喇格区之间的矛盾。为满足不同中心频率器件的设计要求,给出了入射角随截止频率的变化关系。In this paper, we constructed the Dixon equations in tz plane of TeO2 crystal with o→e mode. The θa-f curve was figured out, which was adaptive for ultrasonic beam-steering design. A new optimal design method for the beam-steering anisotropic acousto-optic （AO） deflector was proposed. The bandwidth was expanded under condition of ensuring uniformity in the frequency band. The beam-steering TeO2 anisotropic AO deflector was designed using this method. We compared the design results of the beam-steering device and non-steering device. When relative bandwidths of the two devices were all one octave, the relative AO interaction length of the beam-steering devices would exceed 34.70% over that of the non-steering devices. Under the same condition into Bragg diffraction region, the relative bandwidth of the beam-steering devices would exceed 9.1% over that of the non-steering devices. It was indicated that the beam-steering AO deflector could relax contradiction between the bandwidth and diffraction efficiency, and contradiction between the bandwidth and the condition into Bragg region. In order to satisfy design request for devices with different center frequency, we also calculated the close frequencies vs the different incident angles.

关 键 词：反常声光效应 偏转器 超声跟踪 二氧化碲晶体 

分 类 号：TN65[电子电信—电路与系统]