Numerical investigation of a miniaturized two-dimensional photonic crystal sensor for high-precision optical glucose detection

Purpose This study aims to numerically investigate a compact two-dimensional photonic crystal (2D PhC) glucose sensor based on a dual-waveguide-coupled resonator structure to enhance sensing sensitivity, spectral stability and signal linearity for reliable biosensing in biological media. Design/methodology/approach Two resonator configurations were analyzed: a circular resonator and an optimized elliptical resonator designed to enhance light–matter interaction. The photonic band gap properties were calculated using the plane wave expansion method, while the transmission characteristics and sensing performance were evaluated using two-dimensional finite-difference time-domain (2D-FDTD) simulations. Parametric optimization of the resonator geometry and waveguide coupling was also performed. Findings The circular resonator configuration achieved a refractive index sensitivity of 625–650 nm/RIU. By modifying the resonator geometry to an elliptical shape, the sensor performance significantly improved, reaching a sensitivity of 760–1100 nm/RIU with an enhanced quality factor. The optimized design also demonstrated stable spectral response and good signal linearity, indicating its suitability for accurate glucose detection. Originality/value This work proposes an optimized elliptical resonator integrated into a dual-waveguide PhC platform to enhance glucose sensing performance. The proposed structure provides a balance between high sensitivity, spectral stability and fabrication simplicity, offering a robust simulation-based platform for compact optical biosensors in biomedical applications.