Experimental observation of plasmon-polariton waves supported by a thin metal film of finite width

What are believed to be the first experimental observations of the existence of long-range plasmon-polariton waves, guided by a thin metal film of finite width, are presented. A waveguide composed of an 8-mu m-wide, 20-nm-thick, 3.5-mm-long Au metal film embedded in SiO2 was successfully excited at a free-space wavelength of 1.55 mu m in an end-fire experiment. The theoretical nature of the phenomenon is described, and experimental observations of field confinement provided by this metal waveguide are presented in detail. (C) 2000 Optical Society of America.