Attainment of frequency stable high-energy operation of a CO2TEA laser by use of a telescopic resonator

We describe a hybrid electron-beam sustained TEA CO
2
oscillator using a stable telescopic resonator with a magnification of four. This optical configuration results in good mode selection and a large (11.2 mm e
^-2
radius). TEM
00
mode. Heterodyne determinations reveal that the intrapulse frequency is constant within the experimental accuracy of 50 kHz at the 1 J output level for pulses of duration 3 μs. These results are consistent with the theory of laser-induced medium perturbations.