MULTI-ATMOSPHERIC PRESSURE OPERATION OF A GAIN-SWITCHED IODINE LASER

The operation of a 1.315 mu m atomic iodine laser in the gain-switched mode at multi-atmosphere buffer gas pressures is described. Characterisation of the first gain-switched pulse in terms of pulse delay, energy and peak power has been carried out in the high-pressure regime, and factors influencing the output beam directional stability and optical quality have been investigated. Shock waves generated at the tube walls and photolysis-induced density gradients progressively destroy the optical homogeneity of the gain medium during pumping, but gain-switched, single-transverse mode, operation is possible up to 7 atm maximum pressure. Optical inhomogeneity caused by gain saturation is not detected.