| 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; and 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. A partition or an atrium 405 is provided to allow selective transport of sensed entities to the interface. An alternative version uses an optical fibre stripped of some of its cladding. Preferably the TIR surface has substantially no features with a dimension perpendicular to the surface of greater than 3 microns, more preferably 1 micron. |
