A modified Jamin interferometer has been designed and fabricated to measure very small differences in nearly identical liquids. Instead of an extended source of light, a collimated beam of light is used and the end plates of the instrument are intentionally made wedge shaped. By allowing half of the light beam to pass above the liquids, it is possible to obtain a fiduciary system of fringes thereby obtaining the advantage of the Rayleigh refractometer. In other respects it has been found to be superior to a Rayleigh refractometer.

The processes used to calibrate a field spectroradiometer are described. The spectro-radiometer uses four CVF's and four detectors with two of each in two separate instruments. Wavelength calibration procedure was to illuminate the aperture of the spectroradiometer with energy containing spectral lines at known wavelengths, and to note the linearity of the wavelength signal over the range of the spectral lines. Spectral radiance calibration consisted of comparing analog signals from the detectors to calibrated external references under known conditions.

The fringe contrast observed in real time holographic interferometry is often poor due to depolarization induced by the object. This paper describes the results of an experiment to determine the effect of surface preparation on depolarization.

When a Fresnel zone plate is used as a coded aperture to image large-area sources of X-rays or gamma rays, it is necessary to use a half-tone screen. It is shown here that small-area sources, with such a system, will always produce strong ghost images or artifacts.

Light from a projector lamp is passed through condenser optics and a polariser illuminating uniformly an electron beam actuated Pockels modulator. The modulator rotates the plane of polarisation of the light which is passed to the analyser. The output of the analyser can be projected to a large screen. The electro-optic target consists of an A1203 - ZnS layer structure biased with a d.c. voltage. A charge pattern corresponding to a T.V. image is produced at the interface by electron beam induced conductivity in the A1203 layer. Current gain in the EBIC layer enables low beam currents to be used. By controlling the amount of u.v. in the light, the electro-optic ZnS is rendered sufficiently conductive for the interface charge to decay in a frame time. Calculations show contrast ratios >100:1 could be obtained using a 4 cm diameter target and a brightness of 60 ft lamberts could be achieved on a 12 ft by 9 ft screen, from commercially available arc lamps.

A very inexpensive electronic circuit has been developed for addressing points of interest directly on the bistable screen of storage oscilloscopes by means of an external photodetector operated like a pen. A square marker with internal black cross is displayed on the screen at an intensity level high enough for a good direct view by the operator and low enough for avoiding unwanted spot writing. The marker can be displaced at will on the screen by the operator pen, while at the output of the pen circuit the coordinates of the marker are available in analogic form in order to be used as address signals by a computer.

Investigations on UV-fibers (70 pm and 100 pm) consisting of a quartz core and a cladding of a fluorocarbon resin are discussed. The spectral distribution of the transmission is essentially given by that of the core material so that the light down to 200 nm can be transmitted at reasonable lengths. Above 300 nm the transmission values are comparable to those of regular fibers. The angular distribution of the output differs substantially from that of regular glass-glass optical fibers. Instead of a rectangular distribution expected from theoretical considerations, a bell-shaped curve has been found that is varying both with the wavelength and the optical path. UV-fibers are found to be resistant against intensive ultraviolet and X-ray radia-tion. Resistivity against chemicals, humidity, temperature cycling and continuous exposure to temperatures up to 50°C has been investigated. Finally, UV-fibers have been proved sensitive to lateral pressure, and by this effect,a degradation of the transmission can possibly occur when bending the fibers at too small radii within certain fiber optical components.