A copper vapour laser operating at room temperature

Laser action on the 5106 and 5782 Å lines of neutral copper has been achieved at temperatures from 20 to 140°C in the vapour of copper acetylacetonate, and at temperatures between 150 and 215°C in the vapour of copper nitrate. The peak output powers are compared with those obtained in the vapours of the copper halides CuCl, CuBr and CuI using the same longitudinal discharge operated in a double-pulse mode in low pressure argon. The highest peak power from copper acetylacetonate obtained to date is 5 kW at a temperature of 40°C. The optimum temperature for the nitrate is 180°C at which the peak output power is 20 kW. The halides can give pulses of 50 kW although the temperatures required are much higher. For the acetylacetonate and the nitrate it is necessary to purge the gas mixture of dissociation products by flowing the argon through the discharge tube. It is probable that the resulting reduction in copper density is partly responsible for the poorer performance observed to date with these vapours. Optimum argon pressures and delay times between the two pulses of discharge current were approximately the same for all the copper compounds tested.