Polariton propagation in semiconductors

Summary form only given. Exciton wavefunctions are sensitive to the confinement by sample surfaces, which makes the optical response of a slab very different from that of the infinitely extended medium. This complicated coupling between microscopic exciton polarization and macroscopic optical field has led to a variety of theoretical approaches over 40 years, which either start from a macroscopic approximation or which reduce the full complexity of computing the bulk exciton states by using simplified models or approximations. To address this problem in a direct way, we compute the coupled dynamics of the exciton wavefunction and the propagating electromagnetic field. Within this microscopic treatment we use the correct quantum-mechanical boundary condition for the exciton wavefunction, and no need for additional boundary conditions for the macroscopic polarization arises. The numerical calculations presented here require massively parallel techniques on present-day supercomputers.