We have studied theoretically the inherent mechanisms of nonvolatile holographic storage in doubly doped LiNbO<sub>3</sub> crystals. The photochromic effect of doubly doped LiNbO<sub>3</sub> crystals is discussed, and the criterion for this effect is obtained through the photochromism–bleach factor a=S<sub>21</sub>γ<sub>1</sub>/S<sub>11</sub>γ<sub>2</sub> that we define. The two-center recording and fixing processes are analytically discussed with extended Kukhtarev equations, and analytical expressions for recorded and fixed steady-state space-charge fields as well as temporal behavior during the fixing process are obtained. The effects of microphysical quantities, the macrophotochromic effect on fixing efficiency, and recorded and fixed steady-state space-charge fields, are discussed analytically and numerically.
© 2002 Optical Society of America
Youwen Liu and Liren Liu, "Theoretical investigation of nonvolatile holographic storage in doubly doped lithium niobate crystals," J. Opt. Soc. Am. B 19, 2413-2422 (2002)