Novel thin film materials for plasmonic applications

The performances of an Inverted Surface Plasmon Resonance (ISPR) biosensor based on novel materials have been studied theoretically and experimentally. The principle of ISPR is based on a maximum of reflectivity at the coupling angle instead of the common used minimum of reflectivity; this solution has not been extensively explored yet. The sensor response has been firstly simulated by the use of a dedicated Matlab routine. Different structures involving different materials have been considered and compared, in order to find the optimized solution. The metals have been deposited on a flat substrate made of optical glass. Different noble metals of optimized thickness have been then deposited on top of it. The substrates have been finally coupled with a prism to test the ISPR response. The metallic layers have been deposited at our lab by Electron Beam Evaporation. The process have been optimized for each material considered. The response of the sensors has been tested at our laboratory on a dedicated optical-bench set-up based on the Kretschmann configuration with angular modulation. The theoretical and experimental data are reported. © 2013 SPIE.