Cascaded Bragg gratings in photonic crystal fiber for plasmonic cladding mode-based biosensing of HER2 protein

• DOI: 10.1016/j.snb.2023.133561
• Publication Date: 2023-02-23T03:03:32Z
• Authors: Olga Rusyakina; Thomas Geernaert; Médéric Loyez; Maxime Lobry; Karima Chah; Pawel Mergo; Hugo Thienpont; Christophe Cauche...; Francis Berghmans; Tigran Baghdasaryan
• Keywords: Fiber Bragg Grating; Cladding mode; Cladding (metalworking); PHOSFOS; Long-period fiber grating

Spectral multiplexing of biosensors in a single optical fiber has been long-standing challenge, which we address here for the first time by combining photonic crystal fibers (PCF) with Bragg grating technology. We exploit features transmission spectrum straight written PCF that allows exciting cladding mode resonances within spectral span about 60 nm, is significantly narrower than width spectra tilted gratings standard single-mode step-index fibers. More specifically, consider feature effective index values close to refractive phosphate buffered saline, and demonstrate plasmonic label-free biodetection HER2 (human epidermal growth factor receptor 2) protein. report on simultaneous monitoring wavelength shifts said from two spatially separated biofunctionalized find sensor able detect protein concentration 8.62 nM high reproducibility.