TEA CO2 Laser Oscillation by Using a Fox-Smith Mode Selector with a Fabry-Perot Etalon

For achieving tunable and single longitudinal mode oscillation, a Fox-Smith type mode selector with a Fabry-Perot etalon was incorporated in a TEA CO2 laser. The etalon was inserted in the optical path taken out from the main cavity of the CO2 laser for protecting the etalon from damage on the surface. According to the longitudinal mode resulting from the etalon and the Fox-Smith optical path, the single mode oscillation of purities of more than 99% and 95% was performed with the probabilities of 55% and 100%, respectively. The tunability of a laser frequency was obtained with the purity of more than 75% over the whole gain region of the TEA CO2 laser by controlling the tilting angle of the etalon or the optical path length of the Fox-Smith system.