CO2 laser wave front and beam metrology using Quadri-Wave Lateral Shearing Interferometry

Due to their high power, CO
2
lasers (at wavelength of 10.6µm) are commonly used for engraving, marking or cutting materials in a wide range of industrial applications. They are also used in scientific domains for spectroscopic or LIDAR applications for example. Though many of such lasers are sold over the world, very few instruments are available for intensity profile characterization and even less for wave front measurement. To measure the intensity and the wave front of these lasers, we propose a method based on Quadri-Wave Lateral Shearing Interferometry (QWLSI) [1]. This method allows the complete field analysis of the laser and gives beam parameters such as M
²
, waist position and size, Strehl ratio or far field analysis. The influence of the optical components placed in the laser chain, as well as steady or transient thermal effects can also be evaluated. The prediction of focal spots generated by the entire chain can also be particularly interesting to evaluate marking or cutting processes.