| 摘要 |
An evanescent wave cavity-based optical sensor comprises an optical cavity formed by a pair of highly reflective surfaces such that light within said cavity makes a plurality of passes between said surfaces, an optical path between said surfaces including a reflection from a totally internally reflecting (TIR) surface, said reflection from said TIR surface generating an evanescent wave to provide a sensing function; a light source to inject light into said cavity; and a detector to detect a light level within said cavity; wherein said TIR surface is provided with a functionalising material over at least part of said TIR surface such that said evanescent wave interacts with said material; whereby an interaction between said functionalising material and a target to be sensed is detectable as a change in absorption of said evanescent wave; and wherein said functionalising material comprises a solvating medium to dissolve (convert a gas-phase target to a solution) at said TIR surface. The optical cavity may be replaced by an optical fibre with a reduced cladding thickness at the evanescent region. |
