| 摘要 |
We describe sensing apparatus using evanescent-wave based optical cavity ring-down plasmon resonance techniques. An optical cavity is formed by a pair of highly reflective surfaces, said an optical path between said surfaces including a reflection from a totally internally reflecting (TIR) surface, the reflection from said TIR surface generating an evanescent wave. The TIR surface is provided with electrically conducting material such that the evanescent wave excites a plasmon within the material. A change in absorption of evanescent wave due to a change in said plasmon excitation is detectable to provide a sensing function. Advantageously light of two different wavelengths straddling the plasmon excitation is employed. Preferably the sensor is a fibre-optic evanescent wave surface plasmon sensor.
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