Near-field simulation of obliquely deposited surface-enhanced Raman scattering substrates

A semicontinuous gold layer on a template with a zig-zag structure has been demonstrated to be a highly sensitive substrate for surface-enhanced Raman scattering (SERS). Obliquely deposited gold layers on different templates yield different SERS strengths. In this work, a finite-difference time-domain method is utilized to analyze the electric field distribution within the gold layer when the film is illuminated by light. The random gold nanostructures are scanned and transformed into binary images to allow them to be simulated. The field intensities and SERS enhancement factors of different samples are calculated and compared. Our analysis results reveal the near-field characteristics of strong SERS and agree closely with experimental measurements. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4769806]