双掺杂LiNbO_3∶Fe∶Ru晶体的全息读出特性

Characteristics of Hologram Readout in LiNbO_3∶Fe∶Ru Crystal

为了解决读出过程中全息数据的擦除问题,研究了新型双掺杂LiNbO3∶Fe∶Ru晶体的全息读出特性。分析了双中心和单中心记录方案光栅的读出特性,并联立双中心物质方程和耦合波方程进行了模拟计算。结果表明,双中心记录所得到的饱和全息的读出时间常数远低于LiNbO3∶Fe∶Mn晶体的读出时间常数;单色光记录可以实现有效的全息,且其读出时间常数远大于记录时间常数,表现为准态非挥发读出。分析表明,这可能由于Ru的能级比Mn更靠近Fe,更易被红光激发,从而使得双中心记录所得饱和光栅的存贮持久性降低;单色光记录中红光能够同时充当记录光和抽运光,记录过程中红光能够在Fe上记录光栅并将其转移到Ru上,而在读出过程中则由于Ru能级较深,擦除缓慢。

The readout characteristics for the hologram recorded in the novel LiNbO3 ： Fe： Ru crystal have been investigated in order to resolve the problem of hologram data erasure during readout. Grating readout characteristics for two-center and single-center recording are analyzed, and the simulating calculation is performed through jointly solving the two-center material equations and coupled-wave equations. The results show that the readout time constant for a saturated grating recorded by two center method is much shorter than that in LiNbO3 ：Fe： Mn; an efficient hologram can be realized with one-color recording, the readout time constant is much larger than the recording time constant, and the quasi-nonvolatile readout can be observed. The analysis shows that Ru perhaps is much easier to be excited than Mn by red light, so the grating persistence would decrease; red light can act as recording light and sensitizing light in one-color scheme, and the grating recorded in Fe can be transferred to Ru, which is weakly sensitizing to red light.