The impact of confined phonons on the nonlinear absorption coefficient of a strong electromagnetic wave by confined electrons in compositional superlattices

Abstract. The impact of confined phonons on the nonlinear absorption coefficient (NAC) of a strong electromagnetic wave (EMW) by confined electrons in compositional superlattices is theoretically studied by using the quantum transport equation for electrons. The dependence of the NAC on the energy ( ), the amplitude (E o ) of external strong EMW, the temperature (T) of the system and the period (d A ) of compositional superlattices is obtained in both case of confined and unconfined phonons. Two cases for the absorption: Close to the absorption threshold  and far away from the absorption threshold  (;  and  are the energy of optical phonon and the average energy of electrons, respectively) are considered. The analytic expressions are numerically evaluated, plotted and discussed for a specific of the GaAs-Al 0.3 Ga 0.7 As compositional superlattices. There are more resonant peaks appearing and the values of of the NAC are much larger than they are in case of unconfined phonons.