光诱导光子晶格折射率调制度的实验研究  

Experimental research of refractive index modulation degree about optically induced photonic lattices

作　　者：杨立森[1] 武瑞祥[1] 陆改玲[1] 陈宝东[1] 张宝光[1] 崔俊杰[1] 

机构地区：[1]内蒙古师范大学物理与电子信息学院,内蒙古呼和浩特010022

出　　处：《光电子．激光》2008年第11期1530-1533,共4页Journal of Optoelectronics·Laser

基　　金：国家自然科学基金资助项目(60467002);内蒙自然科学基金资助项目(200408020111)

摘　　要：在不同掺Fe浓度的LiNbO3晶体中,分别用红光和绿光写入光子晶格,利用双光束干涉研究,晶格周期、掺Fe浓度、光波波长与晶格的光致折射率调制度之间的关系。实验结果表明:当用红光(λ=633nm)写入光子晶格时,掺Fe浓度不大于0.05wt%;当用绿光(λ=532nm)写入光子晶格,掺Fe浓度不大于0.03wt%时,LiN-bO3:Fe晶体的光致折射率调制度随晶格周期的变化存在一个极大值,并随掺铁浓度的增加,相应的折射率调制度极大值也增大,且向晶格周期小的方向移动,这与一中心模型理论得到的关系曲线的变化趋势是相一致的;若掺Fe浓度大于以上两值,理论曲线则完全与实验曲线不符,说明一中心模型的空间电荷场理论只适用于小掺Fe浓度的LiNbO3晶体;实验还发现LiNbO3:Fe晶体折射率调制度跟写入光波长有关,用同一块晶体,绿光写入时调制度会比红光更大,且极大值更向晶格周期小的方向移动。Refractive index modulation degree of lighvinduced photonic lattices is studied by utilizing a standard two-beam interference setup in LiNbO3 crystals with different iron doping concentration. The relation between the refractive index modulation degree of light-induced photon lattice and the lattices period,the iron doping concentration and the light wave wavelength are investigated. The experiment result indicates that in these crystals with small iron doping concentration, the experimental rule of refractive index modulation degree changes along with the lattice periods and the iron doping concentration is coincident with the theoretical calculation; while using the crystals with larger iron doping concentration, theoretical calcula tion in terms of the one-center model is futile.

关 键 词：LiNbO_3:Fe晶体 双光束干涉 衍射效率 折射率调制度 光子晶格 

分 类 号：O431.2[机械工程—光学工程]