Abstract

Surface plasmon cross-coupling has been reported recently¹ as a radiative-decay mechanism for molecules near a corrugated thin metal film. To demonstrate this, corrugated photoresist-silver air samples having the same silver film thickness, but different grating periods were fabricated. Since the cross-coupling process is wavelength-dependent, coupling between surface plasmons at opposite sides of the silver film was demonstrated to occur at different wavelengths for samples having different grating periods. In the present experiments, samples having the same grating period but different silver thicknesses were made. The wavelength at which cross-coupling occurs was observed to shift 40 nm toward longer wavelengths as the silver film thickness is decreased. To determine the origin of this shift, the dispersion curve of the silver-photoresist interface surface plasmon was measured and was found to shift toward a larger wave number as the silver film thickness was decreased.

© 1987 Optical Society of America