Frequency locking of two TEA CO₂lasers utilizing a four-wave interaction in SF₆

Abstract

The properties of the simplest phonon-polaritons exist in a two-dimensional diatomic ionic or polar dielectric are investigated by the quantum field theory methods. We considered the two-dimensional crystal as a simple model of a thin slab, an interface or a heterojunction. The Hamiltonian operator describing the interaction between a photon and the phonon mode of the two-dimensional medium is calculated. Anharmonic effects are neglected. The dispersion curves of the phonon-polaritons and the A||-dependence of the electric field strength in each polariton branch are calculated and presented for various case's in a graphical form. It is shown that these properties have close relations with the distribution of the electromagnetic field in the z direction.Recently some of the authors have investigated the exciton-photon interactions by the quantum Green function methods' 15 " 17 '. Orrit et o/.' 15 ' investigated the spectral proper-