(297d) Outstanding Surface Plasmon Resonance Sensitivity and Figure of Merit Enabled By Periodic Gratings Templated from Optical Discs
Surface plasmon resonance (SPR) is a powerful and widely exploited technology for ultrasensitive chemical and biological sensing. Unfortunately, it is generally challenging to simultaneously achieve very high SPR sensitivity and figure of merit (FOM) by using plasmonic nanostructures that can be scalably and economically produced. Here we report a simple and scalable soft-lithography-based templating technology for fabricating plasmonic gratings by using optical discs (DVDs and CDs) as structural template. The resulting Au-coated gratings simultaneously exhibit very high surface plasmon resonance (SPR) sensitivity (up to ~940 nm per refractive index unit, nm/RIU) and figure of merit (FOM, up to ~110). Systematic finite-difference time-domain (FDTD) simulations reveal that the SPR properties (e.g., dip position, amplitude, sensitivity and FOM) of the templated gratings are sensitive functions of the geometries of the track-pitch structures of the optical discs. The numerical simulations agree well with the experimental results. The outstanding SPR performance combined with the wide varieties of functional materials that can be templated (e.g., titania with high thermal stability), as well as the scalability and cost benefits of this bottom-up nanofabrication approach, could make the templated plasmonic gratings a promising SPR platform for many important chemical and biological sensing applications, such as real-time and label-free sensing of biomolecular adsorption, and in-situ probing heterogeneous catalytic reactions under realistic conditions.