INDIRECT COUPLING OF PHOTONS TO SURFACE PLASMON

Some mechanisms are investigated for the coupling of the surface plasma mode in a semi-infinite medium with a flat or almost flat surface to incident electromagnetic waves. In a classical approximation the mechanism of surface roughness (the departure of the surface from a perfectly flat, smooth plane) is studied. Using Green's-function techniques, the coupling of light to the surface plasmon assisted by phonons or impurities is considered. With phonons, the change in the reflectivity due to the mode may be on the verge of measurability at room temperature, while the change in reflectivity with coupling to an irregular surface or impurities near the surface is found to be measurable. © 1968 The American Physical Society.