The effect of the electronic intersubband transitions of quantum dots on the linear and nonlinear optical properties of dot-matrix system

Linear and nonlinear optical dielectric function of an ensemble of randomly distributed quantum dots (QDs) in host material associated with intersubband transition in QDs are theoretically investigated. In this regard, the electronic structure and (linear and nonlinear) dielectric function of the dots are studied using the effective mass theory and the compact-density matrix approach respectively. Maxwell-Garnett method are used to calculate effective dielectric function of dots-host material medium. The results indicate that, by adding QDs, dielectric constant of host material changes dramatically at frequencies which are corresponding to the intersubband transitions of quantum dots. Also at these frequencies, the dielectric function is strongly size dependent and there is a red shift by increasing the radius of QDs. On the other hand, volume density of quantum dots significantly affect the off-resonant frequencies.