An effective antioxidized strategy for Ag based film-dierlectric-metal plasmonic sensor

An effective strategy to avoid the Ag antioxidized problem of the ultra-narrow dualband plasmonic sensors was proposed and demonstrated theoretically by introducing a thin MgF2 layer above the upmost Ag grating surface. The two peaks have different response to the refractive index of the surrounding medium. The resonant wavelength of the sensor is easily tunable via geometrical scaling of the sensor structure and thickness of the MgF2 layer. The sensor is ultrasensitive to the refractive index of the environmental dielectric with the sensitivity as high as 450nm/RIU. This dualband antioxidized plasmonic metamaterial optical absorber has great potential to improve the performance of sensors in practical applications.