Nonlinear Three Photon Process in GaAs and InSb

Three photon absorption coefficients of GaAs and InSb are studied by considering a non-perturbative approach in which final state is represented by a Volkov wave function. By using perturbative approach the coefficients are calculated by taking a two band model. Here both parabolic and non-parabolic band approximation are used with plane and circularly polarized light. The numerical applications of the three photon absorption coefficients in vicinity of the energy gaps are done for GaAs and InSb