A HCN laser and the measurement of the submillimeter wavelength

The design of a CW HCN submillimeter-wave laser is described, and an account is given of its performance. A reflection grating spectrometer and a Fabry-Perot interferometer constructed for measuring the laser output wavelength with accuracies better than 1 percent and 0.1 percent, respectively, are also described. The body of the HCN laser is a Pyrex tube with an inner diameter of 48 mm and a length of 1.35 m. The active length of the glow discharge is approximately 1 m. The cavity consists of a plane mirror and a concave mirror, both of which are coated with gold and have a diameter of 80 mm. The laser output power is shown to be strongly dependent on the gas pressure.