Optical interaction between silver nanocubes and two dimensional silver gratings studied by surface enhanced Raman scattering

摘要

In this article, two dimensional (2D) metallic gratings of different period and silver nanocubes are fabricated and used as the SERS substrate. The SERS signals of rhodamine6G (R6G) on different substrates are compared. Experimental results show that the SERS signals is much weaker if the R6G molecules are placed on the bare silver film, but the signals will be greatly enhanced if the substrates are composed of both the silver nanocubes and metallic gratings. We attribute this enhancement to the coupling between localized surface plasmons and propagating surface plasmons. Further, we study SERS signals from different parts of the 500nm and l000nm period 2D metal gratings including the silver nanocubes. The grating of smaller period shows more reproducibility, which arises from the uniformity in the incident laser coverage.