Effects of time-delayed amplification in TEA CO2lasers

A novel technique is reported for studying the behavior of the time-dependent gain in a TEA CO2amplifier. The method involves the incorporation of an additional amplifier tube into a laser cavity already containing a laser gain tube. The two tubes are independently operated, but so arranged that they can be fired with a controllable time delay between the discharge current pulses. This system permits effects of the additional gain tube on the lasing properties to be investigated as the time delay is varied. In particular, there is a time delay between the discharge current pulse of the laser tube and the onset of lasing. The variations in this delay produced by the firing of the additional amplifier tube have been investigated. The observed time-delay changes can be related to a simple theory for the time-dependent gain. The analysis of the measurements can be used to determine parameters describing the time-dependent gain. This method has been used to measure decay times of the gain for various gas mixtures. The techniques reported here can also be used to study other time-dependent effects within laser amplifiers.