Continuous-wave Stark far-infrared lasing lines in (15)NH(3) optically pumped by a CO(2) or N(2)O laser

Laser emission at 4.5 THz from 15NH3 and a mid-infrared quantum-cascade laser as a pump source

We present an optically pumped terahertz gas laser, which is based on a mid-infrared quantum-cascade laser as a pump source, a transversely pumped standing wave resonator, and ¹⁵NH₃ as a gain medium. We observe several laser lines around 4.5 THz, corresponding to rotational transitions in the ν₂ band of ammonia. So far, these are the highest frequencies obtained from a QCL-pumped THz gas laser. The involved molecular transitions are unambiguously identified by high-resolution spectroscopy.

Sequential optical pumping of a far-infrared ammonia laser

We present a novel technique for resonantly pumping a continuous-wave far-infrared NH(3) laser with a linetunable mid-infrared NH(3) laser that is optically pumped by a CO(2) laser. In this two-step process we first convert 10-microm CO(2) laser photons into 11-13-microm NH(3) laser photons, which are then converted into 60-400-microm photons in a far-infrared NH(3) laser. Continuous-wave laser action on 10 far-infrared lines of (15)NH(3), including four new ones, has been obtained with a single CO(2) laser pump line.