Zeonex-MoS2 hybrid dual-channel terahertz fiber biosensor for multi-analyte detection.

Terahertz (THz) sensing technology, renowned for its non-ionizing nature and fingerprint specificity, faces significant challenges in multi-analyte environments due to the inherent limitations of conventional single-channel surface plasmon resonance (SPR) sensors. These limitations include susceptibility to environmental noise, a restricted dynamic range, and inadequate drift compensation. To address these issues, this work introduces a dual-core dual-channel micro-structured photonic crystal fiber (DC-DC-MPCF) sensor, which integrates independent detection and reference channels for simultaneous analyte detection and systematic error suppression. This sensor uses a molybdenum disulfide (MoS2) excitation layer on a low-loss, water-resistant Zeonex substrate to boost plasmonic field localization and light-matter interactions. Structural innovations, such as a double-D-shaped polished platform and periodic airhole arrays, optimize evanescent field confinement and coupling efficiency between core-guided modes and surface plasmon polaritons (SPPs). Through finite element method (FEM) simulations, critical parameters such as residual cladding thickness (580 µm), ring cavity radius (140 µm), and MoS2 layer thickness (10 µm) are rigorously optimized, achieving a maximum amplitude sensitivity of 162.1895 RIU-1 and wavelength sensitivity of 98087.1 nm/RIU. Simulations confirm that the dual channels operate independently, with the reference channel effectively compensating for environmental disturbances, achieving a wavelength resolution of 1.019 × 10-6 RIU. The sensor demonstrates broad adaptability across a refractive index range of 1.33-1.45, enabling high-precision detection of trace biomolecules such as proteins and DNA. This work establishes a versatile platform for real-time, multi-analyte sensing applications in biomedical diagnostics and environmental monitoring.