An off-center donor and nonlinear absorption spectra of spherical quantum dots

In the present work, off-center donor impurity, the linear and the third-order nonlinear absorption coefficients have been studied by using perturbation method. Numerical results for typical GaAs material show the quantum size effect. Also, we find that the size of the dot, and the position of impurity have a great effect on the linear, the nonlinear and the total absorption coefficients. Additionally, the total optical absorption saturation intensity can be controlled by the size of dot or the incident optical intensity.