Construction and characterization of a CO₂ wave guide laser with a special electrode design for materials processing

We describe the design and construction of an efficient tunable CO₂ wave guide laser which was used for thermal graving of predigitalized images over polymeric materials. The small internal diameter of the cylindrical wave guide allowed the laser operation in high pressure regime ranging from 50 Torr to 100 Torr, which gives higher gain per cavity length. The operation of the laser at 80 Torr with the gas composition CO₂:N₂:He::11:9:60 gave a 400 MHz laser linewidth. For the proposed laser design we used an electrodes configuration which provides a symmetric discharge. The laser cavity, divided into three pieces, show great light coherence.