| 摘要 |
We describe an evanescent wave cavity-based optical sensor. The sensor comprises an optical cavity including a reflection from one or more totally internally reflecting (TIR) surfaces generating an evanescent wave to provide a sensing function; a light source to optically excite said cavity at least two different wavelengths; and a detector to monitor a ring-down characteristic of said cavity at each of said two wavelengths; and wherein said one or more TIR surfaces are provided with at least two functionalising materials one responsive at each of said wavelengths such that an interaction between a said functionalising material and one or more targets to be sensed is detectable as a change in absorption of a said evanescent wave at a said wavelength.
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