Abstract

Apertureless or scattering-type scanning near-field optical microscopy (s-SNOM) conventionally operates with some form of modulation and demodulation technique to generate near-field optical contrast, i.e., to eliminate the usually overwhelmingly strong far-field optical signal background. Unfortunately, such an approach largely prohibits the application of multichannel detectors, rendering s-SNOM spectroscopy a relatively slow, serial measurement technique. To upgrade s-SNOM spectroscopy techniques with the multichannel advantage, near-field discrimination schemes are required, which offer very low far-field background signals. To this end, a very promising approach is the concept of nanofocusing in single crystalline metallic tapers [1,2]. Surface plasmon polaritons (SPPs) are excited on a grating coupler and result in strongly confined near-fields at the taper apex.

© 2015 IEEE