Increase In Raman Excitation Of Surface Polaritons With Surface Roughness Explained In Terms Of Wood Anomalies Of Gratings

Abstract

In a recent publication Ushioda et al. (Phys. Rev. B. 19(8) 4012 (1979)) (henceforth referred to as I) reported an experiment in which Raman excitation of surface polaritons was performed using several rough surfaces. The authors of I observed an increase, with surface roughness, of the Raman scattering intensity, but were unable to give a theoretical explanation of this surprising effect. We suggest an explanation which is based on the similarity existing between Raman excitation of surface polaritons of frequency w along a grating and grating generation of surface polaritons using an incident electromagnetic (EM) wave of the same frequency w. We determine the surface polariton wave along the grating and find a strong enhancement of its intensity when increasing the groove depth. Thus, there is a good qualita-tive agreement between our results and those published in I. This allows us to show that the phenomenon observed by the authors of I is related to the existence of Wood anomalies of gratings.