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 existenc e of long-range plasmon-polariton waves, guided by a thin metal film of fin ite width, are presented. A waveguide composed of an 8-mu m-wide, 20-nm-thi ck, 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 theoret ical nature of the phenomenon is described, and experimental observations o f field confinement provided by this metal waveguide are presented in detai l. (C) 2000 Optical Society of America.