A dual-resonance peak biosensor based on surface plasmon resonance in the terahertz region

Abstract We propose a dual-core, dual-microgroove microstructured fiber biosensor based on surface plasmon resonance (SPR) in the terahertz (THz) region. By coating the two microgrooves with molybdenum disulfide (MoS 2 ) and polyvinylidene fluoride (PVDF), the biosensor enables two distinct and independently tunable SPR peaks. Finite element simulations are used to optimize structural parameters and assess sensing performance. Within the analyte refractive index range of 1.30 to 1.39, the main peak exhibits maximum wavelength and amplitude sensitivities of 467.2 μm RIU −1 and 101.202 RIU −1 , respectively; the secondary peak achieves 625.3 μm RIU −1 and 113.927 RIU −1 . The corresponding figures of merit reach 65.987 RIU −1 (main), and 67.037 RIU −1 (secondary), and demonstrate strong resolution capabilities. This biosensor, featuring an independent dual-resonant peak re-inspection and self-diagnostic mechanism, significantly reduces detection costs and error rates while substantially improving measurement accuracy and interference resistance. The dual-peak response characteristics enable complementary signal enhancement for detecting weak signals and allow real-time instrument status monitoring through analysis of peak position consistency, thereby ensuring result reliability and equipment functionality. It is particularly well-suited for high-risk medical diagnostic applications.