Theoretical investigation of voltage sensitivity enhancement for surface plasmon resonance based optical fiber sensor with a bimetallic layer

Abstract A bimetallic layered surface plasmon resonance (SPR) based optical fiber voltage sensor has been theoretically studied. A gold–silver bimetallic film configuration is utilized to improve both the voltage sensitivity and chemical stability. The thickness of gold–silver metal film and location of single wavelength for monitoring have been analyzed to enhance the sensitivity of sensor. The improvement of voltage sensitivity and its linearity related to voltage are attributable to the electric field enhancement due to the presence of gold–silver film structure. This bimetallic film is capable of simultaneously providing larger voltage sensitivity and better linearity, which is a significant step forward compared to sensors with single gold film structure.