Attainment of frequency stable high-energy operation of a CO2 TEA laser by use of a telescopic resonator

A description is provided of a hybrid electron-beam sustained TEA CO2 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-squared 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 microseconds. These results are consistent with the theory of laser-induced medium perturbations.