| The generation of single CO2 laser pulses, having sub-nanosecond rise and fall time, is described. The duration of these pulses is controlled in the range 0.83 to 100ns and their peak power is of the order of 1 MW. For the generation of these pulses, a double-discharge TEA CO2 laser has been used, in conjunction with an electro-optical shutter. A telescopic CO2 laser amplifier has been employed to amplify the nanosecond pulses to 1 GW power levels. The design and operational characteristics of this device are presented and the effective elimination of associated problems is discussed. The effect of organic vapour additives on the performance of this oscillator-amplifier system is investigated. Experimental evidence is presented indicating an increased efficiency in the amplification of multi-line - as opposed to single line - nanosecond pulses. A novel method for single longitudinal mode operation of pulsed TEA CO2 lasers - incorporating the use of two unstable coupled resonators - has been developed. The powers thereby achieved are in excess of 30 MW. |
