Effects of H2 buffer gas additive on repetition rate scaling of a copper vapour laser

The variations in the output power of a copper vapour laser resulting from H2 additive to neon buffer gas are investigated for a wide range of pulse repetition frequencies (3.2 to 19.7 kHz). Small improvements in laser output power (9%) were observed for ∼2% H2-Ne admixture at low repetition frequency, these improvements becoming progressively larger (up to 250%) as the repetition rate increased. These observations are consistent with added H2 modifying the interpulse kinetics, thereby altering the spatiotemporal evolution of the output pulse. In particular, the observed average output power increases at elevated repetition rates owing to both increased laser pulse energy and increased optimum pulse repetition frequency.