Liu De'an, Liu Liren, Zhou Changhe, Ren Liyong, Li Guangao
Shanghai Institute for Optics and Fine Mechanics, Academia Sinica, China.
Appl Opt. 2002 Nov 10;41(32):6809-14. doi: 10.1364/ao.41.006809.
We report our observation of a bleaching effect under an ultraviolet exposure in LiNbO3:Fe:Cu crystals. Two three-step recording-transferring-fixing schemes are proposed to record nonvolatile photorefractive holograms in such crystals. In the schemes two red laser beams and an ultraviolet illumination are used selectively to write the charge grating inthe shallow-level Fe centers, to develop the charge grating inthe deep-level Cu centers by transferring the charge grating in the Fe centers, and to fix only thecharge grating in the Cu centers for unerasable read-out. Experimental results, verifications, and an optimal recording scheme are given. A comparison of the lithium niobate crystals of the same double-doping system of Fe:Mn, Ce:Mn, Ce:Cu, and Fe:Cu is outlined.
