Plasmon-enhanced absorption by optical phonons in metal-dielectric composites

It is shown that in cermets. with metal percolating clusters in a dielectric host, the metal plasmon modes can strongly couple to the dielectric vibrational modes. optical phonons. In metal-dielectric percolation composites, the plasmon modes are capable of strong accumulation of the electromagnetic energy in small nanometer-sized areas. "hot spots". The local fields in the hot spots can be very large, leading to enhanced absorption by optical phonons of the dielectric. In our experiments, strongly enhanced absorption by the coupled plasmon-phonon modes has been observed in Au-Al2O3 percolation composites.