Investigations on Hologram Fixing Process in Sillenite Type Photorefractive Crystals

The holograms fixing process in very well known sillenite type photorefractive crystals Bi 12 (Ge, Si, Ti)O 20 has important implications for various applications. An effect of prolonged memory of holographic recording with no applied electric field in photorefractive Bi 12 TiO 20 (BTO) crystals at room temperature has been reported. 1,2 The effect is established for high frequency holographic grating with K = 2π/Λ ~ 3×10 5 cm -1 , where Λ is the grating period.