Tunable Raman Selectivity via Randomization of a Rectangular Pattern of Nanodisks

We show that randomization of a nanodisk array on a rectangular lattice can be used to spectrally tune the surface-enhanced Raman scattering (SERS) intensity and to control the field enhancement. The spectral selectivity of the Raman modes exhibits a nonlinear dependence on the extinction. Randomization of the rectangular pattern brings a favorable increase of SERS intensity via a reduced selectivity and extinction changes at the Stokes band. The extinction dependence for two polarizations on the spacing in the rectangular array is demonstrated. For a given polarizations on the extinction strength depends primarily on the spacing between the nanodisks in the orthogonal direction. Such randomization and polarization control of SERS increases the versatility, e.g., all-optical control, of this important sensing tool.