Actively mode-locked transversely excited atmospheric (T.E.A.) CO2 laser

A mode-locked CO2 laser with transverse pulse pumping has been developed which employs a Ge ultrasonic diffraction cell as an active loss modulator. This paper describes the initial stage of an effort to exploit the broad bandwidth (¿ 5 Ghz) of the CO2 laser transition and the high concentration of active gas at atmospheric pressure for generating ultra-short infra-red pulses at 10.6 ¿m wavelength. With the laser system presently described, output pulses with typical durations of about 1 ns and peak powers in the multi-megawatt range have been obtained for the first time.