Dynamical nonlinearity and bistability of narrow gap semiconductors

A brief review is presented of new photo-Hall studies of linear and nonlinear optical properties of narrow gap semiconductors with specific relevance to optical bistability. InSb is chosen as the prototype crystal for this work. The nonlinear refractive cross-section (σ = Δn/ΔN) is determined to be −1.1 × 10−18 cm3 near 5 μm at 77K and −(2.3 ± 1) × 10−18 cm3 near 10 μm at 300 K. The two-photon absorption coefficient is found to be β = 7 cm MW−1. The results are in good agreement with theoretical prediction.