A Novel Thiol-Ene-Epoxy Polymer Based Optical Waveguide for Refractometric Sensing

The utility of planar optical waveguides constructed from a novel thiol-ene-epoxy polymer has been demonstrated for refractive index sensing. The propagating modes supported by this planar structure were excited as well as taken out of the waveguide using the prism coupling method, and detected using an indigenously developed photodetector system comprising a commercial charge-coupled device (CCD) array and an Arduino microcontroller. The mode-dependent refractive index sensitivity was established by considering a monochromatic laser light excitation at 632.8 nm wavelength. The highest sensitivity of this waveguide sensor was found to be 21.84/RIU (refractive index units) and the corresponding refractive index resolution was 4.92 × 10⁻⁴ RIU. The miniaturized version of this optical waveguide sensor has the potential to be integrated within a photonic system for plasmonic-based point-of-care device development.