Optical coupling effects on the performance of 3D SERS bio-sensors

Abstract

While a wide range of substrate formats have been proposed for surface enhanced Raman scattering (SERS) applications, the challenge remains in designing a reproducible high efficiency SERS substrate [1]. In part, this is due to the disconnect between the local field enhancement spectra and the localized surface plasmon resonance (LSPR) spectra commonly used to characterize SERS substrates [2]. It remains a challenge to directly evaluate the sensor performance. In this work, we report a systematic study of optical coupling in SERS substrates by measuring the sensor performance across the visible and near-infrared spectral range. Using the experimental SERS scattering cross section measurements of two distinct peaks we compute the best-fit curve for the field enhancement. Using the field enhancement profile we calculate the full sensor performance maps for both Stokes and anti-Stokes shifts and evaluate the optimal pump laser wavelengths for SERS spectroscopy application.