A new type of local polariton at the interface of gyrotropic enantiomorphic crystals

It is shown that a new type of local polariton can propagate at the interfa ce of enantiomorphic twins-gyrotropic crystals with left-handed and right-h anded rotation of the polarization plane. The wave function of these local polaritons oscillates strongly, with changes of sign, over lengths of the o rder of the lattice constant near the interface, and the period of the spat ial oscillations grows with increasing distance from the interface. The loc al polariton term is detached from the band of delocalized states toward hi gher frequencies. Calculations of the radiation broadening of this term sho w that, for a local polariton, the effect of a giant increase of the decay ("superradiance'') is possible. The magnitude of the polarization rotation due to a local polariton has been found. (C) 1999 American Institute of Phy sics. [S1063-7834(99)02802-6].