Sensitivity enhanced biosensor using one dimensional photonic crystal

Purpose This study aims to design a sensitivity-enhanced biosensor for cancer cell detection using a metal-doped one-dimensional (1D) photonic crystal (PhC) structure. Design/methodology/approach The proposed PhC biosensor consists of alternating BaTiO3 and SiO2 layers, where the BaTiO3 layer is doped with copper (Cu) nanoparticles to improve sensing performance. The optical characteristics of the structure are analyzed using the Transfer Matrix Method, and the biosensor performance is evaluated by observing the resonance wavelength shift with variations in analyte refractive index. Findings The incorporation of Cu nanoparticles narrows the full-width at half-maximum (FWHM) of the resonance peak, leading to sharper spectral responses. The analysis shows a redshift in the resonant wavelength with increasing analyte refractive index, resulting in enhanced sensing performance. The optimized Cu-doped PhC biosensor achieves a theoretical sensitivity of 274.71 nm/RIU, a quality factor of 17621.91 and a figure of merit of 7399.45. Research limitations/implications This study is based on numerical simulations, and the performance of the Cu-doped BaTiO3 PhC biosensor may vary under real experimental conditions. Material fabrication challenges, such as achieving uniform Cu dispersion at higher fill factors, could influence the optical response. Biological samples also exhibit natural variability, which may affect the resonance shift consistency. Despite these limitations, the results highlight the strong potential of Cu-enhanced photonic structures for high-resolution cancer detection. The findings provide a foundation for future experimental validation and may guide the development of compact, highly sensitive biosensing platforms for clinical diagnostics and early disease screening. Practical implications The proposed Cu-doped BaTiO3 PhC biosensor demonstrates high theoretical sensitivity, narrow FWHM and clear spectral separation between normal and cancerous cells, indicating strong potential for practical biomedical use. Its compact 1D structure can be fabricated using existing thin-film and nanophotonic technologies, enabling low-cost, portable cancer-screening devices. The improved optical response achieved through Cu doping could support highly accurate early-diagnosis tools for hospitals, point-of-care testing and personalized medicine. These performance advantages make the design commercially attractive for companies developing next-generation optical biosensors, offering opportunities for investment in scalable production and clinical-grade diagnostic platforms. Originality/value This work proposes a Cu-doped BaTiO3/SiO2 PhC biosensor as a promising platform for high-precision optical sensing. The results provide a useful theoretical basis for future experimental development and the design of highly accurate PhC biosensors.