Amplified backward scattering in LiNbO3:Fe

We study the characteristics of the amplified back-scattered light in a LiNbO₃:Fe crystal cut normal to the optic axis when it is illuminated with a linearly polarized parallel beam of monochromatic light. The scattered light forms different patterns depending on the direction of vibration of the incident beam. The incident beam and the back-scattered beams interfere and generate numerous ‘noisy’ gratings in the volume of the crystal which diffract and amplify selectivity the weak scattered beams. This study is of practical importance since a normally cut LiNbO₃:Fe crystal may be used as a self-starting non-linear adaptive mirror in laser cavities.