Ray-optic analysis of the (bio)sensing ability of ring-cladding hollow waveguides

Ray-optic analysis of transmission spectra and the leakage loss of ring-cladding hollow waveguides suggests that such waveguides offer an attractive platform for the creation of compact and efficient biochemical sensors and sensor arrays. The ring cladding in such waveguides serves as a built-in Fabry-Perot interferometer, allowing the detection of few-nanometer-thick molecular layers and ensuring a high sensitivity of transmission spectra of waveguide modes to small changes in the refractive index of an analyte filling the hollow core and air holes in the waveguide cladding.