Investigation on the blue photorefractive properties varied with MgO codoping in Ru:Fe:LiNbO₃ crystals

Abstract

Mg:Ru:Fe:LiNbO3 crystals with various doping concentration of MgO have been grown by Czochralski method. The type of charge carriers and photorefractive properties in Mg:Ru:Fe:LiNbO3 crystals were measured by two‐wave coupling method using Kr+ laser (476 nm) and He‐Ne laser (633 nm) as light sources. We found that holes were the dominant charge carriers under blue light irradiation while electrons were the dominant charge carriers under red light irradiation. Mg2+ ions behaved no longer as damage resistant, but promoter to the photorefractive properties at 476 nm wavelength. The photorefractive properties under blue light improved with the increase concentration of Mg2+ ions. The enhancement mechanisms of the blue photorefractive were suggested. Experimental results definitely showed that Mg‐doped two‐centre Ru:Fe:LiNbO3 was a promising blue photorefraction material for holographic volume storage.

OH−absorption and nonvolatile holographic storage properties in Mg:Ru:Fe:LiNbO3crystal as a function of Mg concentration

“…[18] Here, holes are the dominant charge carriers under blue exposure. [19] It is found that the blue light is short enough to excite holes both in the shallow and deep trap centres, thus a grating can be directly recorded into the two centres. The repeating cycles of holes excitation-transport-trapping between shallow trap centre and deep trap centre are prohibited, therefore the sensitivity is enhanced compared with that in the conventional two-colour recording.…”

Optimization of Blue Photorefractive Properties and Exponential Gain of Photorefraction in Sc-Doped Ru:Fe:LiNbO3 Crystals

“…Thus, based on the considerations above, two-center Sc:Ru:Fe:LiNbO 3 crystals were grown using the Czochralski method. The incident light wavelength was selected as 476 nm (blue light), which has enough energy to excite the charge carriers' holes of the Sc:Ru:Fe:LiNbO 3 crystals [18]. It was established experimentally that the blue photorefraction of the Ru:Fe:LiNbO 3 doped with Sc was enhanced significantly compared to Sc:Ru:Fe:LiNbO 3 crystals.…”