顺电相KTN中反射型全息相位栅的衍射效率分析  

Diffraction efficiency analysis of reflective holographic phase gratings in paraelectric KTN crystal

作　　者：宋艳生[1] 季家镕[1] 窦文华[2] 温昌礼[1] 

机构地区：[1]国防科学技术大学光电科学与工程学院,长沙410073 [2]国防科学技术大学计算机学院,长沙410073

出　　处：《激光技术》2010年第6期736-738,742,共4页Laser Technology

基　　金：国家八六三高技术研究发展计划资助项目(2007AA01Z2a5)

摘　　要：在顺电相光折变晶体中存储全息相位光栅是研制新型电控全息光开关的有效途径。为了提高光栅的衍射效率,将Kogelnik耦合波理论与Kukhtarev方程相结合,得出了顺电相钽铌酸钾晶体中反射型相位栅衍射效率的解析式,对影响光栅衍射效率的各因素进行了计算分析。结果表明,使写入光的入射角远离45°、增加晶体厚度和增大外加电场等措施都可以使反射型全息相位栅的衍射效率提高。45°入射角附近出现较宽的低衍射区。衍射效率对入射角、晶体厚度以及外加电场的变化敏感,其中任一个参量的较小改变都可以引起衍射效率的较大变化。晶体的吸收对衍射效率的影响可以忽略。分析结果有助于在实践中调整参量以获得较高的读出光衍射效率。The holographic grating storage in photorefi＇active crystal in paraelectric phase is an available approach to develop a new style electroholography switch. In order to improve the diffraction efficiency, the analytic expression was deduced combining Kogelnik coupling wave theory with the Kukhtarev equations. Then the parameters affecting the diffraction efficiency were analyzed. It＇ s found that the diffraction efficiency can be increased by the methods such as aparting the incident angle far from 45°, increasing the crystal thickness and electric field. A low diffraction efficiency district exists at incident angles in vicinity of 45°. Diffraction efficiency is sensitive to incident angles, crystal thickness and applied electric field. A small change of these factors may bring a great difference of the diffraction efficiency. The influence of absorption of crystal on reading diffraction efficiency is negligible. The results provide useful guidelines to choose optimal parameters for high reading diffraction efficiency in practice.

关 键 词：全息 衍射效率 耦合波理论 光折变效应 顺电相 

分 类 号：O438.1[机械工程—光学工程]