title: Theory of critical enhancement of photorefractive beam coupling.
abstract: We develop the idea of critical enhancement of the photorefractive response near the threshold of parametric excitation of space-charge waves (the spatial subharmonics) taking into account the vectorial character of beam coupling and a fairly strong broadening of the nonlinear resonance owing to light absorption. The results of our calculations are a description of the measurable characteristics of critical enhancement and optimization of the experimental conditions for detection of anomalously high amplification gain factors in cubic Bi(12)SiO(20) crystals.
authors: International Institute for Nonlinear Studies, Koptyug Avenue 1, 630090 Novosibirsk, Russia.
authors: E V
authors: EV
authors: Podivilov
authors: B I
authors: BI
authors: Sturman
authors: M V
authors: MV
authors: Gorkunov
authors: V P
authors: VP
authors: Kamenov
authors: K H
authors: KH
authors: Ringhofer