Coupled-Mode Analysis of the Low-Loss Plasmon-Triggered Switching Between the 0 th and -1 st Orders of a Metal Grating

A coupled-wave analysis of the particularly low-loss 0 ^th- and -1 ^st-order switching triggered by the +1 ^st- and -2 ^nd-order excitation of the surface plasmon of an undulated metal surface reveals that the cancelation of the -1 ^st-order diffraction efficiency is due to the destructive interference between the field directly diffracted by the grating and the field coupled to a plasmonic supermode then radiated away by the grating in the direction of the -1 ^st order, the plasmon outcoupling length being much shorter than the absorption length of the excited plasmonic supermode.