Experimental demonstration of an efficient unidirectional coupler for surface plasmons with wide-angle efficiency

We experimentally demonstrated a wide-angle unidirectional excitation of surface plasmon modes. Employing the plasmonic critical angle phenomenon in conjunction with the grating effect, a wide incident angular full-width-half-maximum (AFWHM=25??) with high unidirectionality of extinction ratios better than 10dB was realized. ? 2014 OSA.EI