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.