Investigation of Parity-Time Photonic Crystal Sensor Based on Topological Edge-Defect Mode Hybridization for Oral Cancer Identification

In this study, we propose a parity-time (PT) symmetry-based defected 1D-photonic crystal (PhC) structure operating in the THz regime (0.2–0.4 THz) for the highly sensitive detection of oral cancerous cells. By introducing a complex refractive index profile that satisfies PT symmetry conditions, the proposed design exhibits non-Hermitian properties that enable sharp resonance features and tunable defect mode characteristics. Numerical simulations are carried out by employing finite element and transfer matrix methods, where the results demonstrate that the inclusion of PT-symmetric gain and loss media significantly enhances the sensitivity compared to conventional PhC sensors. We evaluated that the PT symmetry based 1D-PhC structure bestows a sensitivity of 3.0×10 10 %/RIU and 1.1×10 12 %/RIU for gain/loss factor of 1.565488 and 1.613267, respectively. Besides, the design of the structure is simple and feasible to fabricate with available technology, which makes it a right candidate for detection of early-stage oral cancer.