Third-order nonlinear absorption spectra of an impurity in a spherical quantum dot with different confining potential

Abstract

In this study, the linear and third-order nonlinear optical absorption coefficients of intersublevel transitions have been calculated for a spherical CdS/SiO2 quantum dot (QD) with infinite and different finite confining potential by using the density matrix formalism. The electron eigenenergies and the corresponding wavefunctions have been determined by the variational method under the effective mass approximation. We have investigated the effects of the incident optical intensity, QD radius, and confinement potential on the intersublevel optical absorption coefficients. It is found that the size of the dot and depth of the confinement have a great effect on the linear, the nonlinear, and the total absorption coefficients. Also, the total optical absorption saturation intensity is controlled by the strength of the confinement or the incident optical intensity.