Hexagonal Hollow-Core Photonic Crystal Fiber for High-Sensitivity Terahertz Glucose Detection.

Diabetes mellitus is a rapidly escalating global health concern, often leading to severe complications such as neuropathy, vision impairment, vascular dysfunction, and renal failure. In this work, we present a newly designed hexagonal photonic crystal fiber (HPhCF) sensor for the noninvasive detection of urine glucose, offering a compact, fabrication-friendly design. The proposed HPhCF demonstrates strong RS performance across a range of analyte concentrations. Specifically, RS values of 96.90%, 96.86%, 96.40%, 96.35%, 95.88%, and 95.78% are obtained for concentrations of 0-15 mg·dL-1, 0.625 g·dL-1, 1.25 g·dL-1, 2.5 g·dL-1, 5 g·dL-1, and 10 g·dL-1, respectively. These results indicate a gradual decline in sensitivity with increasing analyte concentration, while overall maintaining consistently high performance. Because of its simple structural configuration and compatibility with established photonic fabrication methods, the proposed sensor demonstrates strong potential as a low-cost and highly sensitive diagnostic tool for early-stage diabetes screening and ongoing glucose monitoring in biomedical settings.