Abstract: Apparatus using leakage current through a sample to determine resistivity. An optically active material of the type which changes the polarization of a light beam passing therethrough, responsive to an electric field, is placed between a first pair of conducting plates. The sample is placed between a second pair of conducting plates which are in parallel connection with the first pair of plates. A light source transmits light through the material and a light detector detects changes in polarization of the light which emerges from the material. Each pair of plates is charged and the rate of discharge of the plates is monitored by the light detector.

Abstract: Apparatus for streaking a beam of light employing a crystal in which an electromagnetic wave pulse induces a synthesized traveling lens. Surfaces on opposite sides of the crystal act as light reflectors to create multiple cross-reflections of the beam relative to the crystal, thus to enhance the lensing effect of the crystal. Production of the electromagnetic wave pulse is coordinated with impingement of a beam of light, and the geometry of parts is arranged whereby each coherent wave front in the beam, as it passes multiple times through the crystal, on each such passing encounters the same substantially constant lens condition which has been induced in the crystal.

Abstract: Crystals which vary the polarization of a beam of light according to the intensity of the electrical or magnetic field in the crystal are placed in the vicinity of a high-voltage power line. A laser beam is directed from an elctrically isolated position through the crystal and is reflected to the isolated position. The change in polarization of the returned beam is measured to indicate the intensity of the field. Temperature measurement and thermal compensation are provided because of temperature variations in the polarization modulation coefficient of the crystals.

Abstract: A method for obtaining efficient production of short-wavelength, continuously-tunable ultraviolet light by parametric mixing of optical frequency radiation in a nonlinear crystal. The method involves mixing the second harmonic of a tunable, visible-wavelength laser, an organic dye laser, for example, with the fixed-wavelength output of a near-infrared laser, e.g., a Nd:YAG laser, in a conventional nonlinear crystalline material such as ADP or KDP.