Experimental Comparison of Fiber-Optic Surface Plasmon Resonance Sensors with Multi Metal Layers and Single Silver or Gold Layer

Fiber-optic surface plasmon resonance sensors with multi metal layers (Ti/Ag/Au) and single silver or gold layer are presented. In comparison with widely used single-layer sensors, the multi-layer sensor shows a wider refractive index measurement range (in a range of 1.3344 to 1.4111 RIU) and a better resolution in the high refractive index region (refractive index over 1.3697 RIU). In addition, the sensitivity of multi-layer sensor is between those of sensors with silver and gold layers, the chemical stability, and the film adhesion capability of multi-layer sensor are much better than those of silver layer sensor.