Plasmon excitation on a thin metal-film grating: Profile effect and applications

We investigate plasmon excitation on the surfaces of a thin metal-film grating, which are sinusoidally modulated with a common period and different initial phases. Employing Yasuura's method of modal expansion, we numerically find the resonance angle, field distribution, power flow in the vicinity of the grating surfaces, and efficiency of propagating orders. By setting the amplitude of the metal-film grating and the phase difference between the top and the bottom surface, we can examine the profile effect on plasmon excitation. In addition we show some results for a grating in conical mounting.