By use of an expansion in Gaussian functions we solve the problem of the propagation of a laser beam that has been passed through a thin slab of nonlinearly refracting material. We compare the theoretical results for beam profile with experimental measurements for the semiconductor InSb and confirm that self-defocusing has been observed by D. A. B. Miller, M. H. Mozolowski, A. Miller, and S. D. Smith [Opt. Commun. 27, 133 (1978)]. The deduced value for the nonlinear refractive index at ~5 K is -6 × 10-5 cm2 W-1 at 1886 cm-1. This implies a third-order optical nonlinearity χ(3) ~ 10-2 esu, much larger than any previously reported for a solid.
© 1979 Optical Society of America
D. Weaire, B. S. Wherrett, D. A. B. Miller, and S. D. Smith, "Effect of low-power nonlinear refraction on laser-beam propagation in InSb," Opt. Lett. 4, 331-333 (1979)