Polaron and dielectric mismatch effects on impurity-related optical absorption and refractive index changes in a spherical quantum dot

The influence of both dielectric mismatch and electron-phonon interaction (EPI) effects on the linear and nonlinear optical properties of spherical quantum dots (QDs) with a shallow hydrogenic impurity under electric field are studied. The interplay among confinement geometry, dielectric mismatch, electron-phonon interaction, and the Stark effect on the oscillator strengths, absorption coefficients (ACs) and refractive index changes (RICs) has been revealed. The results show that the polaron effect and/or image charges lead to the blue shifts of absorption coefficients and refractive index changes. As a result of a quantum confinement Stark effect the red shifts of optical characteristics with increasing electric field have been observed. This indicates that the impurity-related optical characteristics of quantum dots can be controlled by the Stark confinement.