Novel Techniques for Enhanced Detection of Blood Components Based on One-Dimensional Photonic Crystal

A novel one-dimensional (1D) photonic crystal (PhC) with multilayered nanostructure with dual defect layer that manages light propagation by creating a photonic bandgap (PBG) is analyzed. Although traditional 1D PhCs consisting of a single defect layer have been shown to possess simple sensing ability, they tend to be restricted by low sensitivity and narrow resonance response, limiting their use for simultaneous detection of multiple analytes. Herein, we report a new design and simulation of an optimized dual-defect-layer 1D photonic crystal for the purposes of multiple sharp resonance modes, enhanced light-matter interaction, and refractive index sensitivity over the single-defect layer structure. The novelty of this work is the choice of the combinations of SiO₂ and ZnO layersto achieve ultrasharp, highly sensitive resonance modes for biosensing applications and optimization of the dual-defect arrangement. The proposed structure has good refractive index contrast with a low-cost thin-film processing. By systematically varying defect layer parameters and leveraging advanced simulation techniques, such as the transfer matrix method (TMM) implemented in MATLAB and finite element modeling in COMSOL Multiphysics, multiple high-Q resonant modes are obtained. In a proof-of-concept, it is shown that the optimized dual-defect PhC is capable of selectively detecting variations in refractive index corresponding to different blood constituents with greatly improved sensitivity and multianalyte detection capability.