Swift heavy ion irradiation of dielectric materials forms latent tracks and selective etching of them results in the formation of well defined nanopores in the material. Irradiation of Au ions accelerated with 137 MeV followed by etching with vapor of hydrofluoric acid successfully formed nanopores with diameter of 30 nm and depth of 400 nm in a waveguide made of amorphous SiO2. In the present research, the nanopores were applied to improve sensitivity of an evanescent-field-coupled waveguide mode sensor that detects adsorption and/or adhesion of molecules at the surface of the waveguide and in the nanopores. Increase in the sensitivity was confirmed by examining the shift in the angular position necessary to excite the waveguide mode before and after adsorption of streptavidin to biotinyl groups.
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