Plasmon mediated Brillouin scattering of surface acoustic waves (in different directions to polymer line structures on a silver coated glass substrate)

In this paper measurement on the propagation of Rayleigh waves on the surface of polymer line structures on top of a silver layer were examined by using plasmon mediated Brillouin scattering. The line structures grating constants were 8, 4 and 1 mu m. Spectra were recorded with different scattering angles and propagation directions with respect to the line direction. Three Rayleigh modes have been observed in samples with grating constants 8 and 4 mu m. In the parallel direction, one mode is unshifted relative to a pure silver surface. In the perpendicular direction there is one unshifted and one shifted mode. The observed shift of 6 mu m(-1) is independent of the grating constant. The 1 mu m sample shows a somewhat contrasting behavior. Two different scattering mechanisms, involving surface plasmons at each interface, are proposed to explain the observed effects. (C) 2007 Elsevier B.V. All rights reserved.