Abstract:

The principle of interferometry has been applied to thin polymer films as they swell by sorption of gases or as they interact with biochemical material. Modern diode array technology allows the monitoring of changes in optical path-length at a fractional nanometre scale. Observation of the interference spectra makes discrimination between thickness and Fresnel refractive index effects possible. Thus, very sensitive sensors can be developed for measuring concentrations of gaseous and liquid organic solvents as well as specific antigen-antibody interactions.