A nanoimprinted plasmonic substrate for both local preconcentration and SERS detection

In this paper, we present a novel plasmonic substrate for both local preconcentration and surface enhanced Raman scattering (SERS) detection. The plasmonic substrate is fabricated by nanoimprint process and then overlaid a thin silver film to adjust the surface plasmon resonance wavelength. Both photothermal conversion and SERS-active wavelength are designed for He-Ne Laser. The measurement process includes three steps. First of all, local concentration is performed by laser induced heating on the plasmonic substrate (over 100°C) to create a small bubble in high power mode (10mW). Then turn off the laser, the target analyte (Rhodamine 6G solution) will concentrate to the center as the bubble disappeared. Finally, the SERS spectra are taken in low power mode (1mW). The intensity of SERS signal at the concentrated region is an order of magnitude larger than the untreated region. The repeatability of this preconcentration process makes it a good candidate to amplify small SERS signals especially for trace detections.