Helical TEA-CO2 Lasers

Abstract

A transversely excited atmospheric TEA–CO2 laser having a helical electrode configuration is described and analyzed. This laser configuration possesses a radial gain profile which naturally favors the excitation of the lowest-order mode of the resonator. Pulses of 0.7 J, having a peak power close to 1 MW, have been obtained in the fundamental mode. However, a strong diverging lens effect caused by the transverse electric discharges in the laser cavity produces a far field beam divergence twice as small as that calculated from the geometry of the resonator. This lens effect has also been used to lase with some geometrically unstable cavities. Two independent types of measurements, performed to study this lens effect, are shown to agree with a proposed theoretical model.