Zeonex-based high sensitivity dual-channel SPR optical fiber sensor for gaseous analytes in terahertz regime

A Zeonex based dual-channel optical fiber Surface Plasmon Resonance (SPR) sensor has been proposed in this paper for gaseous analytes in terahertz regime. The subwavelength porous polymer fiber is surrounded by two semicircular air hole channels and the SPR effect can be excited by the ferroelectric polyvinylidene fluoride (PVDF) layer coated on the inner surface of the channels. A thin dielectric layer is used to enhance the coupling efficiency between the fundamental mode and the surface plasmon polariton mode. Using Finite Element Method, simulation results show that the sensitivity of the sensor can reach 110,000 nm/RIU, which is more than twice the sensitivity proposed by other existing THz optical fiber sensors. Moreover, the dual-channel design and the penetration of terahertz waves facilitate multi-channel detection, making it practical for biomedical and chemical fields.