Exciton surface polaritons on organic crystals

Abstract

Exciton surface polaritons (ESP's) are electromagnetic waves which are localized at solid surfaces and have exponentially decaying electric fields on either side of the interface. They are nonradiative, that is, they cannot be excited by photons incident on a plane surface, but they can be excited by an evanescent wave from a prism coupler not in contact with the surface for angles of incidence beyond the critical. We have identified some organic solids that could support these modes at optical and near ultraviolet wavelengths at room temperature. Calculations are presented of the attenuated total reflectivity as a function of angle of incidence at wavelengths within the polariton stop band of the solids. In addition calculations of the intensity of the electromagnetic field in the prism, gap, and sample are given to illustrate the resonance enhancement of the field intensity at the crystal surface when the ESP is excited. © 1978 American Institute of Physics.