Time resolved H atom density measurements in a Cu HyBrID laser

We are presently developing nonlinear spectroscopic techniques for measuring the spatio-temporal density behaviour of H and halogen atoms species to investigate the action of these species in halogen enhanced copper lasers. In this paper, we report time resolved measurements of ground-state H atom density in a Cu HyBrID laser obtained using two-photon allowed laser induced fluorescence. Ultraviolet probe radiation (205nm) was focussed through an end window to excite the n=3 level and the resultant Balmer fluorescence detected via a side window. The results indicate that the H atom density is depleted to less than half its prepulse value during the excitation pulse and then recovers almost fully during the first 20 microseconds of the interpulse period. By interrupting the discharge, we also have used the technique to investigate the H reassociation rate at the tube wall. The results suggest the technique, which may also be adapted to obtain halogen densities and gas temperature measurements, is a promising diagnostic for investigating halogen enhanced Cu laser vapor plasmas.