Calculation of the Nonlinear Absorption Coefficient of an Intense Electromagnetic Wave Caused by Confined Electrons in Doped Semiconductor Superlattices

General analytic expressions for the absorption coefficient (ACF) of an intense electromagnetic wave (IEW) caused by confined electrons in doped semiconductor superlattices (DSSL) are obtained by using the quantum kinetic equation (QKE) for electrons in the case of electron-optical phonon scattering. A second-order multiphoton process is included in the result. The dependence of the ACF on the amplitude E-0 and the photon energy (h) over bar Omega of an IEW, the plasma frequency omega(p) and the temperature T for a specific DSSL of n-GaA.s/p-GaAs is achieved by using a numerical method. The computational results show that the dependence of ACF on the photon energy can be applied to optically detect the electric subbands in a DSSL.