Exciton-photon coupling in photonic wires

Cavity-polariton mode dispersion and exciton-photon coupling effects have been investigated by angle-resolved photoluminescence in a two dimensionally confined semiconductor Bragg microcavity (photonic wires) with a quantum well (QW) inserted in the cavity layer. The lateral photon confinement results in the appearance of additional photonic modes. The strong exciton-photon coupling leads to the formation of cavity polaritons with energy-wave vector dispersion corresponding to the photonic wires with ideal QW's (the coupling only between the photon and exciton modes with the same lateral symmetry). The small influence of QW potential fluctuations disturbing exciton lateral symmetry undoubtedly shows that the polaritons form via coherent collective exciton states.