We report what is to our knowledge the first cw, dc-excited, fast-axial-flow CO2 laser using a variable-reflectivity output coupler. A super-Gaussian reflectivity profile of order 8 with 96% central reflectivity has been achieved by depositing a low-absorption coating onto a ZnSe substrate. The unstable resonator oscillated in the lowest-order mode to produce a diffraction-limited beam of 300 W of power and 0.35-mrad divergence angle (FWHM). The measured near field and far field are in good agreement with the mathematical model. The technique lends itself to extrapolation to the kilowatt level.
© 1990 Optical Society of America
Original Manuscript: June 19, 1990
Manuscript Accepted: October 21, 1990
Published: December 15, 1990
P. Sona, G. Sherman, Ch. Leys, and P. Muys, "High-power fast-axial-flow CO2 laser with a variable-reflectivity output coupler," Opt. Lett. 15, 1452-1454 (1990)