Surface plasmon resonance sensor based on bimetallic alloys grating
A surface plasmon resonance sensor based on triangular alloys grating with high performance is proposed. The grating consists of homogeneous binary gold alloys of formula Au
 x
 M1−x
 , where M is silver, platinum and palladium. It is observed that the two metals, platinum and palladium, have an almost identical surface plasmon resonance in gold alloys irrespective of composition x. The resonance sensitivity becomes highly dependent on gold composition. The composition of gold around 0.1 is found to have a higher sensitivity. 0.1 composition of Au and 0.9 of Ag gives a high sensitivity. Consequently, the quality of the sensor is improved. Numerical simulations show that the angular sensitivity of the sensor reaches 100°/RIU and the full width at half maximum of the resonant dip is only 1.2°. Moreover, the sensor has not only a high sensitivity and a high resolution, but also a good linearity.