Quasi-nonvolatile holographic storage in doubly-doped LiNbO_3 crystals

摘要

The recording and readout characteristics in doubly-doped LiNbO_3 crystal with one-color scheme are investigated based on jointly solving material equations and coupled-wave equations. Asymmetry between grating buildup and readout process is found when electrons in deep centers can be excited by recording light; the grating is quasi-nonvolatile. The shorter recording wavelength, and dopant in deep centers with a closer energy level to Fe in LiNbO_3 crystal, can strengthen such asymmetry. The further investigation shows that two aspects induce the quasi-nonvolatile behavior in doubly-doped LiNbO_3 crystal, one is the beam coupling between incident and diffracted beams, the other is two grating form in both centers. This research provides a possible method to prolong the lifetime of grating in doubly-doped LiNbO_3 crystals.