Beam quality enhancement for an radio-frequency excited Annular CO2 laser

We report the preliminary experimental results obtained from an annular radio-frequency excited CO2 laser with a Talbot cavity and a phase correcting mirror external to the cavity. The Talbot cavity is adopted in order to reduce the number of oscillating azimuthal modes. The use of the external profile-modulated mirror is aimed at reducing the beam phase modulation and thus increasing the amount of fundamental annular mode energy content. The beam quality results to be sensibly increased. (C) 1998 American Institute of Physics