High Tunability, High Beam Quality CO2 Laser with SFUR Cavity and Beam Expander

The performances of the multi-atmosphere transverse excitation CO2 laser can be significantly improved by using a new design SFUR (self filtering unstable resonator) cavity, modified in order to have continuous tunability. In this work, a beam expander is used as a zoom to match the plane grating to the appropriate SFUR focal length, with a suitable expansion to avoid grating damages. The theory and results of our solution are described.