Radiation Greenʹs function of a DBR cavity containing a quantum well: vacuum photons and cavity polaritons on equal footing

Radiation Greenʹs function has been derived for cavity polaritons, which describes the propagation of electromagnetic field in- and outside the system consisting of DBRs and a quantum well with an exciton resonance. This Greenʹs function equally describes both the cavity polaritons with leakage to vacuum and the vacuum photons disturbed by the cavity. The convolution of this Greenʹs function with an arbitrary current source, such as those due to various nonlinear polarizations, pump phonons fields, and so on, directly gives the signal field due to the source.