Experimental Verification of the Shift between Near-Field and Far-Field Peak Intensities in Plasmonic Nanoantennas

P. ALONSO; P. ALBELLA; F. NEUBRECH; C. HUCK; J. CHEN; F. GOLMAR; F. CASANOVA; L. HUESO; A. PUCCI; J. AIZPURUA; R. HILLENBRAND

Salt Lake City, Utah,

Conferencia; 13th International Conference on near-field optics, nanophotonics and related techniques, NFO 13; 2014

Plasmonic nanoantennas show a large potential for application in optical microscopy, sensing and communication on the nanometer scale, owing to the strongly enhanced near-fields in the antenna vicinity and their strong far-field extinction. Recently, a distinct spectral shift between the near- and far-field optical responses of plasmonic antennas has been predicted [1] and indicated by a few experimental studies [2]. Here, we will present a combined study of near-field optical microscopy and far-field spectroscopy of individual infrared-resonant nanoantennas that provides an experimental verification of this spectral shift. Numerical calculations corroborate our experimental results. We will also discuss the implications of this effect in surface-enhanced infrared spectroscopy (SEIRS). [1] J. Zuloaga, and P. Nordlander, Nano Letters, 11, 1280 (2011) [2] J. Chen, P. Albella, Z. Pirzadeh, P. Alonso-González, F. Huth, S. Bonetti, V. Bonanni, J. Åkerman, J. Nogués, P. Vavassori, A. Dmitriev, J. Aizpurua, and R. Hillenbrand, Small, 7, 2341 (2011)