Sun, M.Savenko, I. G.Flayac, H.Liew, T. C. H.2017-05-012017-05-012017-05-01201710.1038/srep45243https://infoscience.epfl.ch/handle/20.500.14299/136760WOS:000398106100001We consider exciton-photon coupling in semiconductor microcavities in which separate periodic potentials have been embedded for excitons and photons. We show theoretically that this system supports degenerate ground-states appearing at non-zero inplane momenta, corresponding to multiple valleys in reciprocal space, which are further separated in polarization corresponding to a polarization-valley coupling in the system. Aside forming a basis for valleytronics, the multivalley dispersion is predicted to allow for spontaneous momentum symmetry breaking and two-mode squeezing under non-resonant and resonant excitation, respectively.text::journal::journal article::research article