ENHANCEMENT OF TM-TE MODE CONVERSION CAUSED BY EXCITATION OF SURFACE PLASMONS ON A METAL GRATING AND ITS APPLICATION FOR REFRACTIVE INDEX MEASUREMENT

Abstract

Yasuura's mode-matching method is employed in the investigation of plasmon resonance absorption on a metal grating with a gold over-coating and the results are compared with experimental data. Enhancement of TM-TE mode conversion accompanying the plasmon resonance absorption is examined. When a TM wave is incident on a metal grating, enhanced TM-TE mode conversion occurs at angles of incidence at which the surface plasmons are excited. The strength of the mode conversion depends strongly on the azimuth angle of the mounting. This is verified by experiment and an application for refractive index measurement is suggested.