Experimental cross-polarization detection of coupling far-field light to highly confined plasmonic gap modes via nanoantennas

摘要

We experimentally demonstrate the coupling of far-field light to highlyconfined plasmonic gap modes via connected nanoantennas. The excitation ofplasmonic gap modes is shown to depend on the polarization, position andwavelength of the incident beam. Far-field measurements performed in crossedpolarization allow for the detection of extremely weak signals re-emitted fromgap waveguides and can increase the signal-to-noise ratio dramatically.