A simple displacement fibre optic sensor is proposed which is based upon the principle of frustrated total internal reflection. The simple designs considered overcome the problems inherent with the small distances involved with frustrated total internal reflection.
A. W. Palmer,
J. R. Croft,
"Potential Applications For Total Internal Reflection Fibre Optic Sensors", Proc. SPIE 0374, Fibre Optics '83, (30 August 1983); doi: 10.1117/12.934585; https://doi.org/10.1117/12.934585