Effects of Ar and Ne diluents on the output power of Xecl lasers are experimentally studied for the Xe CI lasers transversely excited byashort-pulse (40 ns) electron-beam. We used many gas mixtures: Ar, Ar/HCl, Ar/F₂, Ne, Ne/HCl and N₂, to precisely measure the electron-beam energy deposited into the laser gas mixtures. According to the measurement, it is verified that the deposition energy measured in a pure rare-gas and a mixture of rare-gas and halogen gas gives always less energy than the value converted from the energy deposited in the pure N₂, because of the considerable spontaneous emission loss in the related rare-gas mixtures. The value converted from the N₂ is found rather correct. For a 2-atm mixture of Ar, Xe, and HCl pumped with an excitation rate of 0.95MW/cm³ ·atm, the intrinsic efficiency is 3.3%, while it is 2.5% for a 3-atm mixture of Ne, Xe, and HCI pumped with a rate of 0.60MW/cm³ ·atm.

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Various catalysts were tested and evaluated for enhancing the output power of sealed-off CO₂ lasers by suppressing the CO₂ dissociation in the discharge tube. They include (i) two kinds of distributed heterogenous catalysts, i. e. sputtered Pt layer and ion-exchanged Pt on MnO₂ layer both on the internal surface of laser tube, (ii) homogeneous H₂ catalyst generated from the equilibrium dissociation of Nb H_x and finally (iii) catalytic cathode made of La_1-xSr_x CO₃ perovskite oxide.
Among them, the La_0.7 Sr_0.3 CO₃ cathode sintered at 1150°C acted satisfactorily producing the output power of 52W/m, which was almost equal to that of a gas flowing laser. The longest life of this laser was 4400h at the discharge current of 15mA. This excellent performance resulted from the simultaneous presence of metallic conductivity, catalytic activity, oxygen emissivity and low sputtering rate in the perovskite cathode material.

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An automated measuring apparatus based on the thermocouple laser calorimetry is developed. The absorption coefficients of CVD Zn Se specimens are measured with this technique. The accuracy is within ±5% and a measurent is completed in less than 10 minutes. The total absorption is resolved into bulk absorption and surface one having approximately 8×10^-4cm^-1 and 2×10^-4/surface respectively. The absorption coefficients increase up to the level of 10^-2-10^-1cm^-1 owing to pore defects and/or powder defects. The dependence of absorption coefficient on the measurement's position is observed and the absorption coefficients are found to be almost uniform in case of non-defect disk shaped specimen.

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