Nonlinear dynamics of dipolaritonic optical parametric oscillator

Abstract

Mixed exciton–photon states in planar semiconductor microcavities with quantum wells in the active layer belong to a new class of quasi two dimensional states with unique properties. They arise due to a strong coupling of excitons with eigenmodes of electromagnetic radiation of a microcavity, as a result of which upper and lower exciton–polariton microcavity modes are formed. Large interest is drawn to polariton–polariton scattering, due to which the exciton–polariton system demonstrates strongly nonlinear properties. Along with exciton–polaritons, a new bosonic quasi-particle (dipolariton), is formed in coupled double quantum wells (QWs) in a microcavity and was observed for the first time in [1]. In comparison with an exciton–polariton, a dipolariton is a superposition of microcavity photon and direct and indirect excitons. Here, the direct exciton is a bound state of a pair of electron and hole from the same well, and the indirect exciton is formed by coupling an electron and a hole from neighboring wells. The coupling of microcavity photon with direct and indirect excitons leads to the formation of eigenmodes of the system with three dispersion branches: lower, intermediate, and upper dipolariton branches [2]. Due to the large dipole moment of dipolariton, the latter has been proposed as an ideal quasi-particle for generating THz radiation. However, despite the significant progress in the experimental study of dipolaritons, rigorous theoretical consideration of their physical properties is absent. Therefore, further studies in this field are urgent.