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Oxygen‐related thermal donor formation in Czochralski silicon is characterized by the capacitance‐voltage and deep level transient spectroscopy techniques as a function of 450 °C anneal time following hydrogenation. Increases in the formation rate and number of thermal donor (TD) defects found after hydrogenation are reported. This study finds an increase in TD+/++ concentration in the near‐surface region at short anneal times, but at longer times an elevated concentration was not observed. No acceleration through the sequence of thermal donor defects was detected. This fails to support the model of hydrogen lowering the barrier to oxygen diffusion and accelerating the TDn→TDn+1 transitions. This study does, however, support a model in which the hydrogen increases the available thermal donor core sites.

A passively mode−locked TEA CO2 laser has been operated with an unstable resonator, and mode−locked trains with peak powers ≳150 MW, together with near diffraction−limited beams, have been obtained. Single axial mode operation at a power level of 14 MW has also been achieved. These results represent a significant improvement over similarly dimensioned systems using stable resonators.

The stabilization and extension of operation of XeCl (308 nm) and KrCl (222 nm) excimer lasers by the addition of very low concentrations of hydrogen gas is described. Lifetime extension of a sealed‐off XeCl laser operating at 8 W and 150 Hz is reported, with more than three million shots to half power. Spectroscopic analysis of the laser gas indicates a large reduction in a discharge‐induced absorption feature below 230 nm; no absorption is observed at 308 nm.

A 0.3‐GW, 60‐ns TEA CO2 laser has been used to create plasma from a solid carbon target. Studies of the x‐ray emission from the plasma at 4×1011 W/cm2 indicate the existence of a high‐energy electron component with an equivalent temperature of ∼ 2 keV.