Design and simulation of a photonic crystal-based optical sensor with low detection limit and high sensitivity for blood glucose measurement

• In this study, a photonic crystal structure consisting of air holes in a silicon substrate is used as an optical sensor for detecting glucose concentration in human blood. • This sensor offers high precision and selectivity performance by taking advantage of the optical bandgap properties of periodic structures. • The proposed sensor has a quality factor ranging from 7480 to 7487. In this study, a photonic crystal structure consisting of air holes in a silicon substrate has been designed and simulated as an optical sensor for detecting glucose concentration in human blood. This sensor offers high precision and selectivity performance by taking advantage of the optical bandgap properties of periodic structures. The obtained results show that the proposed sensor has a quality factor ranging from 7480 to 7487, a sensitivity between 1428 and 2592 nm per unit refractive index change, a figure of merit (FOM) between 7140 and 12960, and a limit of detection (LOD) ranging from 7 × 10⁻⁶ to 1.4 × 10⁻⁵ RIU. These values indicate the excellent performance of the sensor in label-free, real-time, and accurate glucose monitoring in biomedical applications. This sensor works invasively by analyzing a small volume of blood introduced into the sensing area, allowing real-time glucose detection with high accuracy.