Beam fanning and double phase conjugation in a fiber-like photorefractive sample

Unexpectedly fast response (35 ms) of beam fanning has been measured in a fiber-like photorefractive sample of Bi/sub 12/TiO/sub 20/ (BTO) crystal. Nonlinear interaction between different directions of fanned beams is responsible for unusual angular distribution of the fanning emerged from the fiber that can be used for double phase-conjugate mirror (DPCM) recording with higher efficiency in a wider range of the pump's incidence than in a bulk sample. The DPCM with conversion efficiency up to 8% has been recorded in the BTO fiber at /spl lambda/=632.8 nm for a 2/spl times/3 mW input light power. Practically, it means that no adjustment is needed to achieve an effective interaction of mutually incoherent beams, except introducing the pump beam into the fiber.<
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