Unstable resonator with semitransparent output coupler for transverse-flow CO2 laser

摘要

Abstract: An unstable resonator with semitransparent output coupler (NRPOZ) and low magnification is investigated theoretically and experimentally for Fresnel numbers 5 - 15 and small signal gain 0.5 - 2.4. With the help of numerical simulation the condition of minimum diffraction losses is found. The beam divergence in the dc-discharge transverse-flow kilowatt-power CO$-2$/ laser was approximately two times less in comparison with telescopic unstable resonator without substantial loss of mode volume and output power.!10