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: A differential laser gyro, of the type having four modes, to define a first gyro operating with both clockwise and anticlockwise right circular polarized circulating waves, and a second gyro operating with clockwise and anticlockwise left circular polarized circulating waves, is provided with reflective optical readout paths in which the anticlockwise waves are coupled through an odd number of mirrors (or vice versa), and then through a mode-combining beam splitter, to provide two colinear beams, each including all four modes, to identical assemblies of polarization conversion and discrimination means and heterodyning detectors.

Abstract: An improved laser gain tube for use in a differential laser gyro is disclosed. The gain tube comprises a housing having a cathode located therein with a pair of chambers located within the cathode, a pair of discharge tubes extending from anode regions on each side of the cathode into each of the chambers and means for providing an electrical discharge within the chambers. An aperture positioned between the chambers is adapted to provide optical communication therebetween while maintaining electrical isolation of an electrical discharge in each chamber. The chamber walls are adapted for maintaining the discharge with a current density below the threshold for cathode sputtering.