High photorefractive gain at counterpropagating geometry in CdTe:Ge at 1.064 μm and 1.55 μm

Recording of efficient reflection holograms is achieved in CdTe:Ge at A = 1.064 mu m and A = 1.55 mu m. The gain factor measured at both wavelengths for counterpropagating two-beam coupling considerably exceeds the absorption constant and transcends all values previously reported for semiconductors with no external field. The dependences of the gain factor on intensity and grating spacing are studied. Some crystal characteristics are estimated in the frame of a single band, one mobile species approximation of space-charge formation. The homogeneity of photorefractive properties in the crystal volume is demonstrated. (c) 2009 Optical Society of America