An efficient cavity for optically pumped terahertz lasers

Abstract The efficiency of a simply designed cavity for optically pumped pulsed terahertz lasers is studied experimentally. A coated Ge and a crystal quartz act as the input and output windows, respectively. The thickness of the Ge window is designed according to etalon effects to maximize terahertz reflectivity. NH 3 is filled in the cavity as the active medium. When NH 3 is pumped by the 10P(32) line of a TEA CO 2 laser, intense 151.5 μm terahertz radiation is emitted. As high as 19.6 mJ terahertz radiation is extracted from 1.57 J pump energy. The corresponding photon conversion efficiency reaches 35.3%.

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