Abstract
A zigzag quasilongitudinally (ϑ=15°) CO2 laser‐pumped D2O oscillator at 66 μ is described. Maximum energy was 42 mJ in a 2.5‐μs pulse, representing ∼9% quantum conversion efficiency. The spectrum was only a few axial modes wide. With a single‐pass mirrorless arrangement, a strong superradiant signal was observed, spatially following the CO2 beam at 15° to the axis and easily distinguishable from a weak axial emission.