Optically induced variable light deflection by anisotropic Bragg diffraction in photorefractive KNbO_3

Abstract

Photoinduced anisotropic Bragg diffraction in photorefractive coefficient KNbO3 using the electro-optic r42 = 380 pm/V has been studied. It has been demonstrated that, by using a noncritical configuration, a He–Ne laser beam with fixed incidence angle can be deflected within a range of 5.67 deg by changing the wavelength λr of the Ar+ laser beams used for recording the photorefractive grating (wavelength tuning range; 457.9 nm < λr < 514.5 nm). It is shown that for the reported interaction angles between recording and diffracted beams, the Bragg condition is noncritically fulfilled for the whole deflection range without any beam tilting being required.