Output beam propagation and beam quality from a multimode stable-cavity laser

The beam quality and propagation characteristics of the output beam from a multimode stable-cavity laser are studied. Experimental beam propagation measurement for the output beam of a coaxial electrical discharge CO2 laser are performed. The fundamental beam parameters are then evaluated using the geometrical parameters of the stable resonator. Results show that the equipartition of the the laser's ouput power over the full set of tranverse modes in the cavity aperture is strongly dependent on the device's gain profile.