Abstract: A laser gyroscope is formed as a sealed, unitary assembly of mirrors optically contacted to a monolithic gyro block without any means, such as Brewster windows, for isolating the laser plasma from any of the mirrors. The mirrors are fabricated with hard multilayer dielectric films which can withstand plasma exposure. A magnetic mirror utilizing the transverse Kerr effect to separate the frequencies of counter-propagating beams, and to avoid lock-in, includes a Ni-Fe alloy layer over which is directly deposited a thin iron or iron alloy layer to form a rotationally switchable Kerr effect combination. The magnetic field for switching is generated by an electric current developed in two pairs of orthogonally disposed wires embedded in the substrate immediately below the iron and Ni-Fe alloy layers.

Abstract: Method and apparatus for high accuracy measurement of non-reciprocal reflectivity of magnetic thin film materials and magnetic mirrors. An ellipsometer which employs a Helmholtz coil to supply magneto-optic modulation to p-polarized light and an acousto-optic modulator to provide intensity modulation is utilized in conjunction with a novel scheme of analyzer rotation and computational techniques to accurately measure non-reciprocal reflectivity. A microcomputer is used to provide controlled rotation of polarizing elements, data logging, data analysis, and output. The non-reciprocal reflectivity value is determined by the slope of the measured ratio of magneto-optically modulated and absolute intensities (.delta.I.sub.magnetic /I.sub.total), plotted against a function of the analyzer angle G(.PSI.).