Image Number 2 for United States Patent #4595377.
Method of fabricating an cold cathode for a laser such as ring laser gyro characterized by the use of vitreous carbon as the material of the cathode. For this purpose a predetermined amount of resin is pressed formed into the shape of a hollowed cathode body which is then heated in an oxygen free environment form a vitreous shaped cathode by thermal degradation of the resinous body. The vitreous carbon material reduces the difference between the coefficients of thermal expansion of the housing and electrode which can cause the indium seal to fail, e.g., in the case of prior aluminum cathode. The electrical connection may be made via either a silver epoxy or indium solder.