敏化光波长对(Fe,Ni)∶LiNbO_3晶体全息记录性能的影响

Effect of Wavelength of Sensitizing Light on Holographic Storage Properties of(Fe,Ni)∶LiNbO_3 Crystal

分别采用514 nm绿光4、88 nm蓝光和390 nm紫外光作为敏化光,633 nm红光作为记录光,详细研究了敏化光波长对氧化(Fe,Ni)∶LiNbO3晶体全息记录性能的影响。结果表明:随着敏化光波长的逐渐减小,氧化(Fe,Ni)∶LiNbO3晶体的非挥发全息记录性能逐渐优化,390 nm紫外光是这三种敏化光中最优的敏化光。考虑敏化光的吸收,为了在双中心全息记录中获得最优的性能,应当选择合适波长的敏化光:一方面短波长敏化光能有效地敏化深中心;另一方面短波长敏化光的吸收太强(如对光折变效应无用的基质吸收),不能沿厚度方向有效地敏化晶体,所以实际上需折衷考虑,并从理论上给予了解释。

By sensitizing with 514 nm green light, 488 nm blue light and 390 nm ultraviolet light respectively, recording with 633 nm red light, the effect of wavelength of sensitizing light on holographic storage properties of oxidized （Fe, Ni） ： LiNbO3 crystal is investigated in detail. It is shown that by shortening the wavelength of sensitizing light gradually, nonvolatile holographic recording properties of oxidized （Fe, Ni） ： LiNbO3 crystal is optimized gradually, and 390 nm ultraviolet light is found to be the best among the three kinds of sensitizing light. Considering the absorption of sensitizing light, appropriate sensitizing light wavelength should be adopted to obtain the best performance in two-center holographic recording. On one hand the sensitizing light with short wavelength can sensitize the deep center effectively, on the other hand the absorption is too strong, for example the substrate absorption which is useless for photorefraction, to allow valid sensitization in the thickness direction. So in practice a trade-off is always needed. Explanation is also presented theoretically.