Energy transfer in two-wave mixing quasi-degenerated in photorefractive crystals

B Barrera,M L Molina Prado,M Tebaldi,N A Arias Hernández

doi:10.1088/1742-6596/687/1/012085

B Barrera, M L Molina Prado + Show 2 more

Open Access

https://doi.org/10.1088/1742-6596/687/1/012085

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Abstract

Wave equations describing the quasi-degenerated two-beam coupling in the photorefractive crystals for high frequency gratings have been solved. In the case of the quasi-degenerate two-beam coupling, equations depend upon the coupling coefficient, the response time of the medium, the input beams frequencies, the absorption coefficient and the input intensity ratio. The response time of the medium is function of the diffusion field, the drift field, the saturation field and the concentration ratio, i.e., the ratio between NA density of acceptor impurities and ND density of donor impurities. The effect of these parameters on the gain has been studied in details.

Highlights

Photorefractive crystals make possible an energy transfer from the reference or pump beam into the signal beam
Wave equations describing the quasi-degenerated two-beam coupling in the photorefractive crystals for high frequency gratings have been solved
Wave equations describing the quasi-degenerated two-beam coupling in the photorefractive crystals have been analysed

Summary

Introduction

Photorefractive crystals make possible an energy transfer from the reference or pump beam into the signal beam. The coupling of interacting beams in dynamic hologram recording in photorefractive media has been extensively studied due to their potential applications in signal processing, optical communications, optical computing, real-time holography, image enhancement and holographic memories. The nonuniform pattern received by the crystal results in a refractive index change due to the photorefractive and linear electro-optic effect. This index grating can be considered a volume dynamic grating. In experiments using non stationary conditions of recording, the energy transfer between the two beams takes place due to a phase mismatch between the incident light intensity grating in the crystal and the photoinduced index grating produced inside the crystal. The beams intensities dependence on the material response, the diffusion field, the saturation field, the drift field, the characteristic time of the medium and the concentration ratio are discussed

Theoretical discussion

Results

Conclusions