High near-ultraviolet Raman efficiency of silicon nanowires with small cross sections

Abstract

Due to peculiar near-UV Si optical properties, Mie resonance (MR) and MR-assisted Raman enhancement >10${}^{2}$ are observed in Si nanowires (NWs) with unusually small (for MR) cross sections of \ensuremath{\sim}10${}^{2}$ nm${}^{2}$. The superposition of MR with the Si Raman susceptibility peak is found to produce a record high for Si structure Raman efficiency and makes single Si NW Raman signals detectable at subnanowatt laser power. Experimental NW width dependencies of the Raman and absorption efficiencies are found to be in agreement with calculations based on solving Maxwell equations using the boundary integral equations method.