Material optimization of doubly doped LiNbO3 crystals for high-diffraction efficiency and low-scattering noise in nonvolatile holographic storage

摘要

Scattering noise in four kinds of lithium niobate crystals of the same doubly doping system (they are LiNbO_3:Fe:Mn, LiNbO_3:Ce:Mn, LiNbO_3:Ce:Cu and LiNbO_3:Fe:Cu) is observed during nonvolatile holographic recording. The results show that nonvolatile holographic recording can effectively suppress scattering noise and this kind of suppression effect is decided by the recombination coefficients of the dopants in the shallower and the deeper centers, respectively. It is concluded that small recombination coefficients of the shallower centers and large recombination coefficients of the deeper centers benefit the amplification of the signal grating and the suppression of the noise grating. In addition, the initial seed scattering noise also impacts the finally suppressed scattering noise and little initial seed scattering leads to low scattering noise after recording. In a conclusion, the performances of LiNbO_3:Ce:Cu is the best with high diffraction efficiency and low scattering noise. The theoretical simulations are performed for validation. It provides a fundamental method to the problem of scattering noise intrinsic into the nonvolatile holographic recording.