Experimental characterization of RF-discharge open slab CO2 lasers

We have studied the properties of RF-discharge CO2 lasers based on a hybrid-guided free-space planar resonator, Such a resonator shows some advantages over totally guided slab lasers. These latter lasers proved to have an optimal power extraction but a poor transverse mode selectivity. On the contrary, the resonator with free-space boundary conditions on the wide transverse direction reveals a better mode selectivity and also the possibility of emitting on the fundamental mode, together with a power extraction only slightly lower than totally guided lasers. Moreover, our electrodes' shape lends itself to the construction of high power arrays of slab- lasers. The maximum extracted power from a 2 x 15 x 320 mm(3) discharge unit operated sealed-off with a xenon-free gas mixture, is 48 W. The maximum efficiency is 13.5%.