Polaritons in semiconductor multiple-quantum-well structures with Förster-type interwell coupling

When the barrier potential is high enough and/or its thickness large enough resonance tunneling becomes negligible in multiple-quantum-well structures. In this case a possible mechanism to connect the quantum wells is a Förster-type interwell coupling that originates from the long-range electron-hole exchange interaction. We theoretically investigate excitons in such a coupled multiple-quantum-well structure subject to an external light field, and show that the resulting polaritons behave in a qualitatively different way than those in uncoupled quantum-well structures. Of particular interest are interbranch polariton transitions and the redistribution of the radiative damping rate between different polariton branches. Numerical calculations are performed for a CdS-coupled double-quantum-well structure with dephasing by phonons taken into account.