No abstract

No abstract

No abstract

A recording liquid interferometer with a sensing volume of only 4 mu l and a lower detection limit of refractive index of less than 2*10-7 has been developed using the narrow beam of a small helium-neon gas laser. The instrument was originally designed for the detection of liquid chromatographic effluents in small-diameter packed capillary columns. It is suitable for use at high liquid pressures (e.g. 50 kg cm-2), as in the study of volume elasticity, and probably also as a detector in supercritical fluid-phase chromatography, using a separation technique recently developed in our laboratory. A special and more versatile phase-to-voltage converter was devised to record the optical phase shift in the interferometer. The instrument and some experimental results obtained with it are described.

A novel opto-electronic system for the ellipsometric analysis of thin films is described. Based on interferometric principles, the instrument permits accurate (σΔ=0.25° and σψ=0.05°) and fast (down to 5 ms) measurements. Spectroscopic applications seem promising, because the use of chromatic optical components has been avoided. The availability of an absolute reference rules out the possibility of systematic errors due to imperfections of components and of the window of the measuring cell used in ultra-high vacuum experiments.