Experimental investigation of a method for controlling the shape of radiation pulses from a CO2 amplifier

A method for controlling the shape and duration of a radiation pulse, formed in a CO₂ amplifying system with fast excitation of the active medium, was investigated for the first time. The method was based on the difference between the times of release of energy from the vibrational states of CO₂ and N₂. Control over the pulse shape was achieved by varying the delay time τ_d between the start of excitation of the optically active medium of the amplifier and the time at which the master oscillator radiation was injected. The duration of the output signal was varied over the range 0.06–2 μsec with a practically constant amplification efficiency of ~10%. The maximum compression of a pulse, under the conditions of the present experiment, was limited to a time of ~60 nsec due to the finite rate of rise of the leading edge of the master oscillator pulse and due to the processes of energy relaxation from the vibrational and rotational states of the CO₂ molecules in the optically active medium.