Ultra-sensitive mid-infrared copper based fiber surface plasmon resonance sensor using two-dimensional transition metal dichalcogenides

Abstract

In this paper, a copper (Cu) based fiber surface plasmon resonance (SPR) sensor using two-dimensional (2D) transition metal dichalcogenides (TMDs) is studied theoretically. As the number of layers of TMDs increases, the sensitivity first increases and then decreases, exhibiting a maximum value for each TMDs based fiber SPR sensor. The maximum sensitivities of the fiber SPR sensors with WS2, MoS2, WSe2 and MoSe2 are up to 47.664 µm/RIU, 44.164 µm/RIU, 46.704 µm/RIU and 48.816 µm/RIU, while their resonance wavelengths are 3481.1 nm, 3592.2 nm, 3500.8 nm and 3435.1 nm. In addition, the growth rate of sensitivity in the mid-infrared regime is obviously higher than that in the visible or near-infrared regime. The proposed Cu based fiber SPR sensor with 2D TMDs exhibits ultra-high sensitivity in the mid-infrared regime, and can be used for highly sensitive bio-sensing.