PHOTOREFRACTIVE EFFECT IN CDGA2SE4

We report the first observation of the photorefractive effect in a def ect chalcopyrite semiconductor CdGa2Se4. At 633 nm wavelength, the pho torefractive two-beam coupling gain was measured for 0.62 mum grating period with rotating the crystal around the nearly [110] axis for both the s-polarised signal and pump beams and the p-polarized beams. The maximum gain 0.88 cm-1 for the rotation angle was obtained when the gr ating wave vector was oriented to the [001] axis for the s-polarized b eams.