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The absorption characteristic of lithium niobate crystals doped with chromium and copper (Cr and Cu) is investigated. We find that there are two at)parent absorption bands for LiNb[O.sub.3]:Cr:Cu crystal doped with 0.14 wt.%, [Cr.sub.2][O.sub.3] and 0.011 wt. % CuO; one is around 480 nm, and the other is around 660 nm. With a decrease in the doping composition of C r and an increase in the doping composition of Cu, no apparent absorption band in the shorter wavelength range exists. The higher the doping level of Cr, the larger the absorbance around 660 ran. Although a 633 nm red light is located in the absorption band around 660 nm, the absorption at 633 nm does not help the photorefractive process; i.e., unlike other doubly doped crystals, for example. LiNb[O.sub.3]:Fe:Mn crystal, a nonvolatile holographic recording can be realized by a 633 nm red light as the recording light and a 390 nm UV light as the sensitizing light. For LiNb[O.sub.3]:Cr:Cu crystals, by changing the recording light from a 633 nm red light to a 514 nm green light, sensitizing with a 390 nm UV light; and a 488 nm blue light, respectively, a nonvolatile holographic recording can be realized. Doping the appropriate Cr (for example, No, 2.795 x [10.sup.25] [m.sup.-3] and [N.sub.Cr]/[N.sub.Co] = 1) benefits the improvement of holographic recording properties. OCIS codes: 050.7330. 090.2900, 160.5320. 210.2860, 300.1030.