DEVICE FOR PRODUCING STIMULATED INFRARED EMISSION, IRASER, BY MEANS OF AN ELECTRIC DISCHARGE IN A GAS MIXTURE CONSISTING PARTLY OF CARBONIC ACID GAS, AND DISCHARGE TUBE DESTINED FOR SUCH A DEVICE

1,205,204. Lasers. PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd. 12 Feb., 1969 [15 Feb., 1968], No. 7631/69. Heading H1C. In order to compensate for the absorption of water vapour in the walls of the discharge tube of an infra-red gaseous laser the active medium of which comprises carbon dioxide, nitrogen, helium and water vapour a substance, e.g. zeolite saturated entirely or partly with water is placed in contact with the active medium. The substance is in equilibrium with water vapour whose pressure lies betwen 0À1 and 0À3 Torr inclusive and the water is drawn off as required to maintain the water vapour pressure at the required value. In the laser described the active medium is contained in a cylindrical quartz tube sealed at one end by a gold coated concave quartz block and at the other end by a flat germanium plate. A rod of zeolite is positioned in a side tube of the discharge tube.