Development of a Surface-Plasmon Resonance Sensor Testbed for Bimetallic Sensors

Gold-based surface plasmon resonance (SPR) sensors coupled with microfluidic lab-on-a-chip technology offer exciting possibilities for real-time, in situ environmental monitoring and water quality control, due to their small size and portability. However, one barrier to their wide adoption has been their limited accuracy and sensitivity compared to laboratory-based techniques. We present analytical data generated via the transfer-matrix method which show that these issues can be addressed by replacing the gold plasmonic films in the sensors with silver films of similar thickness. Furthermore, reducing the silver thickness slightly to make room for a gold capping layer has minimal impact on plasmonic performance but is likely to improve the resilience of the sensors. Finally, we describe an experimental testbed for the evaluation of such bimetallic SPR sensors and present calibration data generated with gold sensors exposed to both water and air.