Short-wavelength far-infrared laser cavity yielding new lines in methanol

We report 16 new laser lines generated in a short-wavelength far-infrared Fabry-Perot laser cavity. The CO(2) pump laser is coupled into the far-infrared laser outside the far-infrared laser mode, and the cavity uses a 45 degrees adjustable output coupling mirror; this combination results in a low-loss Fabry-Perot cavity for wavelengths below 150 microm. The new lines are of medium and strong intensity and have wavelengths in the region 26.2-125.7 microm.