RESUMO
A novel type of unstable resonator is described, and its operation with a CO(2) laser is discussed. The laser mode is rectangular in cross section, and the field is inverted about a line that makes a 45 degrees angle with the edge of the beam during a round-trip pass. Beam inversion, low magnification, and reasonably low sensitivity to misalignment allow efficient power extraction from low-gain lasing media while also outcoupling a solid rectangular beam. A beam quality of 1.1 was observed. The beam quality varied from 1.1 to 1.6 during misalignment of the rear rooftop mirror by ~0.06 mrad. A further misalignment of ~0.03 mrad stopped the lasing.
RESUMO
A simple theory describing the annular converging wave resonator has been developed. The theory explains results obtained in two recent experiments. Configurations of the converging wave resonator that could be used to extract power from a large-volume annular gain region in a single mode with nonzero azimuthal order are also discussed.