双掺杂铌酸锂晶体中体全息记录的振荡特性研究

Oscillation Characteristics of Two-center Holographic Recordings in LiNbO_3∶Fe∶Cu Crystal

分析了双中心记录初始阶段振荡现象的产生机制,研究了晶体掺杂浓度和记录光与UV光的束比对记录初期阶段振荡特性的影响.结果表明,振荡现象可以归因于记录介质双能级中心深浅能级电子数平衡分布的改变.在浅能级掺杂浓度较小的晶体中记录时,振荡强度较大;记录光与UV门光束的光束比越大,振荡持续时间越短.

The oscillation feature of the holographic grating at the initial phase of two-center holographic recording in double-doped LiNbO3 ： Fe ： Cu crystal was investigated. The oscillation behavior could be attributed to the transfer of electron distributions in the deep and shallow trap centers of the double-doped crystals at the initial phase of recording,from the initial distribution of just finishing a pre-exposure with UV light to another equilibrium distribution. In experiments, the effect of doping concentration ratio and the intensity ratio of recording beams to UV light on oscillation characteristics was explored. The results show that the strength and the duration of the oscillation are dependent on doping concentration of the shallower trap in crystals and the intensity ratio of total recording beams to UV light.