A compact sealed pulsed CO2TEA laser

A compact sealed pulsed CO
2
TEA laser with an operational life exceeding 10
⁶
pulses has been developed. It provides single-mode output pulses of 1.0-MW peak power in 50-ns full width at half maximum (FWHM) and total energy 110 mJ in 2 μs. The output beam emerges from an 8.5-mm-diam aperture with a full-angle divergence of 3.5 mrad, which is less than 1.5 times the diffraction limited value. With a different optical resonator system, the corresponding multi-mode output exceeds 1.4 MW in 80 ns with a total energy of 300-500 mJ delivered in 4 μs and with a beam divergence of about 10 mrad. These output levels, corresponding to 15-25 J/l, are obtained for a pulse repetition frequency of 2 Hz and are maintained after initial conditioning, even in lasers tested to
2 \times 10^{6}
pulses. Hitherto, prolonged sealed operation was not possible because the glow discharge degraded into arcs. This has been overcome in the present device by the addition of small quantities of carbon monoxide and hydrogen to the basic CO
2
-N
2
-He-laser gas mixture before seal-off.