Fiber refractive index sensor based on Surface Plasmon Resonance in triangular pyramid structure

A refractive index (RI) sensor based on Surface Plasmon Resonance (SPR) in triangular pyramid structures is proposed. The sensor is fabricated by a silver coated triangular pyramid structure at the end of single-mode fiber. We analyze the effect of the thickness of the metal layer using numerical simulations. The theoretical results show that triangular pyramid structures can effectively stimulate the Surface Plasmon Wave (SPW), and a good transmission dip can be obtained when the silver film thickness is between 30 to 40 nm. According to the numerical simulation results, when the thickness of the film is 30nm, the average sensitivity can reach 2590 nm/RIU in the RI range of 1.33–1.41.