Evanescent field-assisted intensity modulation of surface-enhanced Raman scattering from a single plasmonic nanowire

Abstract

In this paper, we experimentally show how polarization of evanescent optical fields can be used to modulate surface-enhanced Raman scattering (SERS) intensity from a chemically prepared, single silver nanowire. By systematically varying the input polarization between p and s polarization, we observed a modulation depth of 0.88 in SERS intensity. The scattered output light was polarized perpendicularly to the nanowire axis with a modulation depth of 0.90. Our method of SERS excitation of a single nanowire in total internal reflection geometry can be further utilized as an evanescent-mode nano-optical sensor, especially in cases where soft nanomaterials are employed for molecular detection.