Spectral measurement of the nonlinear refractive index in ZnSe using self-bending of a pulsed laser beam

The nonlinear refractive-index (n(2)) spectrum of ZnSe near the band gap (lambda(gap) approximately 450 nm) at 77 K was measured for the first time to our knowledge by using self-bending of a pulsed laser beam. The maximum nonlinearity, n(2) approximately 1.9 x 10(-8) cm(2)/W, measured by us is anomalously large, which cannot be explained by conventional thermally induced band-gap shrinkage.