FLUID ANALYSIS USING PHOTONIC CRYSTAL WAVEGUIDE

摘要

Fluid analysis may be achieved according to embodiments of the present invention by introducing a water-based analyte into a hollow core region (1000) of a photonic crystal waveguide, for example a photonic crystal fibre, acting as a liquid core waveguide. The waveguide has, around the core region, a microstructured cladding region (1020), which comprises a silica matrix (1060) filled with a periodic array of air holes (1040). The waveguide is able to guide a wide range of wavelengths of light, including excitation and sensing wavelengths of light, through the analyte by total internal reflection in the core region. This is possible because the cladding region of a photonic crystal waveguide can be arranged to have an effective refractive index lower than water, even though silica has a refractive index higher than water. Many other analytes, with even lower refractive indices than water, may be tested according to other embodiments of the present invention.