Third order nonlinear optical properties of a one and two electron spherical quantum dot with and without a hydrogenic impurity

OpenAlex İngilizce

In this study, a detailed investigation of the nonlinear optical properties of a spherical quantum dot (QD) containing one and two electrons has been carried out. First, intersublevel linear, third-order, and total absorptions of both single- and double-electron QDs have been investigated for cases with (i.e., D0 and D− donor) and without impurity. Second, linear, third-order, and total refractive indices have been examined in the same structure. In the calculation of optical properties, for the density of electrons in the QD considered, some symbolic values chosen are not similar to those in previous studies. The full numeric matrix diagonalization technique has been employed in determining sublevel energy eigenvalues and their wave functions. The Poisson–Schrödinger equations have been solved self-consistently in the Hartree approximation. In addition, the quantum mechanical many-body effects have been taken into account in local density approximation. The results are presented as a function of QD radii, photon intensities, and photon energies. It is found out that although magnitudes of the linear absorption coefficients are the same for cases with and without impurity, the third-order ones are larger, and so the total absorption coefficients are smaller in the case without impurity. It is also observed that the size of the QD and the intensity of the illumination have drastic effects on nonlinear optical properties.