The effects of the selective addition of the gases H 2 , CO, O 2 , NO, NO 2 , and N 2 O on the output peak power and stability of a flowing-gas TEA laser operating with a basic mixture of CO 2 , N 2 , and He are examined. These additive gases are possible products of reactions which occur in the discharge region of the laser and have considerable bearing on the operation of a sealed TEA laser. The power output is increased with the limited addition of H 2 (∼5 percent) or NO (∼0.2 percent), whereas N 2 O, NO 2 , O 2 , and CO reduce the power output when present in any amount; 50-percent reduction being obtained with ∼0.23-percent N 2 O, ∼0.15-percent NO 2 , ∼4-percent O 2 , and ∼22-percent CO. H 2 (and possible NO) limits the transition from a diffuse glow to are discharge by allowing a larger range of operating conditions, whereas CO reduces the range of operating conditions for stable operation. O 2 does not affect the discharge, whereas N 2 O and NO 2 both encourage the transition to arcing.

The effects of gas additives on TEA CO 2 lasers

In this investigation the degraded gas mixture in a sealed TE CO 2 laser discharge was analyzed gas-chromatographically, which enabled us to determine the concentration of CO accurately, even in the presence of large quantities of N 2 . According to the reversible decomposition reaction 2CO 2 \rightleftharpoons 2CO + O 2 , [CO]/2[O 2 ], which should be unity, was found to be noticeably more than unity. The deviation of the O 2 concentration from that needed to satisfy the CO 2 decomposition equation was more than 26 percent. No oxides of nitrogen were detected and the missing oxygen was recovered when the degraded gas mixture was heated to the dissociation temperature of ozone.

Gas-chromatographic studies of the products in a sealed TE CO 2 laser discharge

Calculations and measurements of different plasma parameters of the HCN-laser discharge are presented. A qualitative explanation of the chemistry of the non-isothermal plasma can be given by the comparison of existing theories and experimental results.

Parameters and chemistry of the HCN-laser plasma

The measurement of the degree of dissociation and a discussion of the formation of excited laser-active HCN molecules are presented. It is shown that HCN molecules formed by chemical reactions on the wall of the discharge tube contribute significantly to the laser gain and cause the experimentally observed constant gain over the resonator.

Wall processes and radial gain of the cw HCN laser

The existence of two sources of the photionization in UV preionized sealed CO2‐N2‐He‐(CO) lasers has been established. One is steadily created in the laser gas mixture by the electrical discharge and is identified as NO and NO2. The second source is associated with an impurity in any CO gas used as part of the initial gas mixture.

H. J. Schötzau

Papers

Mass spectroscopy of the plasma of cw and TEA CO2-laser discharges☆

A water-cooled hollow cathode for continuous HCN-lasers

Mass spectroscopy of glow discharges in submillimeter-wave lasers