Absorption characteristic and nonvolatile holographic recording in LiNbO_3:Cr:Cu crystals

Abstract

The absorption characteristic of lithium niobate crystals doped with chromium and copper (Cr and Cu) is investigated. We find that there are two apparent absorption bands for LiNbO3:Cr:Cu crystal doped with 0.14 wt.% Cr2O3 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 Cr 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 nm. 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, LiNbO3: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 LiNbO3: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, NCr = 2.795 x 10(25) m(-3) and NCr/NCu = 1) benefits the improvement of holographic recording properties.

Absorption characteristic and two-center holographic recording in LiNbO3:Ce:Ru crystals

“…From 1998, the development of new materials with different dopants has become an important direction for two-center recording [3][4][5] . In 2005, An Fe and Ru codoped LiNbO3 was reported to perform two-center recording, a high sensitivity of 0.12cm/J and a large dynamic range of 0.53 were obtained in a 0.5 mm-thick crystal with 465nm sensitizing and 633nm recording [6][7] .…”

Computer modelling of trivalent metal dopants in lithium niobate

“…In addition, co-doping by In and Sc also increases the photo-damage threshold [10]. For LiNbO 3 :Cr:Cu crystals, a non-volatile holographic recording can be obtained, and an appropriate Cr doping level helps improve the holographic recording properties [11]. In a very recent paper, Cr has been suggested as a versatile probe for mapping ferroelectric domain inversion in LiNbO 3 [12].…”

Near infrared nonvolatile holographic recording in doubly doped LiNbO 3 :Fe crystals

“…In the absence of the sensitizing wavelength, hologram in shallow traps will be erased, while hologram in deep traps is fixed and readout is nonvolatile. Differently doped LiNbO 3 crystals have been applied in two-center holographic recording [7][8][9][10], and 633nm and 514nm are always adopted as recording wavelengths.…”