Three-wave mixing with high amplification in a photorefractive polymer

We demonstrate that in photorefractive polymer by crossing a strong and a weak beams one can achieve high intensity gains when the angle between them is small. The amplification of the weak wave is accompanied by the formation of the third beam produced by the strong beam diffraction into the -1 order. The gain obtained by the mechanism of three-wave mixing are much higher than the gains produced by earlier reported mechanisms. The experimental results are agree with the theoretical results obtained with the earlier for photorefractive crystals.