Interlevel optical properties of systems of quantum dots

Abstract

Infrared interlevel electromagnetic response of different quantum dot (QD) systems is investigated theoretically within the self-consistent field approach. Individual QDs as well as lattices of QDs electromagnetically interacting are considered. The Coulomb interaction in the QD systems is shown to essentially affect the optical spectra of the systems. Systems of QDs with uniaxial rotation symmetry are considered. It is shown that the shape of QD can dramatically affect the spectra, in particular, depending on the polarization of incident radiation and number of electrons in the dot. It is shown that the Coulomb interaction in the QD systems causes the depolarization shift of the peak(s) in the spectra, can affect the peak(s) height, and cause the peak split. It is numerically established that the approximation of the point dipole-dipole interaction can be used for adequate representation of the effect of the dynamic interdot electron-electron interaction on the spectra of the considered QD lattices. It is found that the effects of the intradot and interdot Coulomb interactions on the response can be analyzed separately. Effect of the intradot electron-electron interaction on the spectra is considered for different QD sizes and shapes. Illustrative maps of the interlevel transitions are utilized to facilitate application of the approach of the modified oscillator strength for reproducing the absorption spectra of the considered QD systems with interacting modes of the collective excitation. The results obtained can be useful for designing nanooptoelectronics devises based on the QDs, and engineering composite materials including the QDs with predermined optical properties.