No abstract

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.

In this work a simple fibre optic device using infra-red radiation is used to obtain information on the timing of the cardiac cycle and blood volume changes in the flow of blood in the body. The device is small, non-invasive and free from interference by surrounding electromagnetic fields enabling it to be used in the environment of such devices as NMR scanners.