Diffraction efficiency in quasi-degenerate coupling in photorefractive materials

VILLAMIZAR AMADO, ASTRID LORENA; LIZARAZO, ZANDRA; ARIAS HERNÁNDEZ, NÉSTOR ALONSO; MOLINA PRADO, MARTHA LUCÍA; TEBALDI, MYRIAN

BISTUA REVISTA DE LA FACULTAD DE CIENCIAS BASICAS

Universidad de Pamplona

Año: 2019 vol. 17

0120-4211

The aim of this work is to present theoretical analysis of the diffraction efficiency in sillenite BTOcrystal, for mobile transmission gratings, where the effects of coupling beams are significant [1-5].In case of the degenerate coupling in photorefractive materials, the efficiency depends of the crystalthickness, coupling coefficient and the input intensity ratio. In the non-degenerate coupling case, thediffraction efficiency also depends on the response time of the photorefractive medium [6]. Thisresponse time is the function of concentration ratio [7], i.e., of the relation between acceptor numbersand donor numbers. The diffraction efficiency is obtained by using coupled wave equations in on-Bragg regime using Method Runge-Kutta of order 4 in Matlab. The analysis considers the non-uniformity of the gratings inside the crystal, the concentration ratio of the material and detuningfrequency .