Nonlinear susceptibility of InSb at the wavelength of 10.6 µ

The nonlinear susceptibilities of InSb were determined at 10.6 µ and their relaxation times were found. In the case of noncoherent signal and reference waves the reflection due to the four-wave interaction was found to be dominated by the third-order nonlinear susceptibility χ⁽³⁾ ≈10^–7 cgs esu with a relaxation time ~10^–11 sec. In the coherent interaction case the reflection was dominated by the fifth-order nonlinear susceptibility χ⁽⁵⁾≈10^–8 cgs esu with a relaxation time ~10^–8 sec.