Topologically Enhanced One-Dimensional Photonic Crystal Sensor for High-Precision Thermal Detection

This work presents a topological one-dimensional photonic crystal (1DPhC) mirror heterostructure thermal sensor that incorporates a glycerin defect layer to achieve unprecedented thermal sensing performance. By leveraging the high thermo-optic coefficient of glycerin, the design achieves an exceptional combination of sensitivity (0.1177 nm/°C), ultrahigh quality factor (~ 1.8 × 10⁸), and record figure of merit (~ 15,341.75°C⁻¹), surpassing both conventional and previously reported topological PhC sensors. The synergy between the topological configuration and the strongly tunable glycerin layer yields robust spectral confinement and sensing efficiency that remains robust even with significant temperature-induced refractive index changes in the glycerin layer. Systematic optimization identifies a 500 nm glycerin defect as optimal for maximizing the balance between field confinement and thermal response, offering practical design guidance for next-generation sensors. The proposed device, compatible with scalable fabrication via glycerin infiltration techniques, holds strong potential for integration into compact, on-chip environmental and biomedical sensing platforms, marking a significant advancement in high-precision photonic thermal detection.