Abstract: Laser radiation whose wavelength is in the submillimeter wave spectral region is sent through an intercavity dielectric tube positioned inside a coil. The tube contains a gas having large dipole moments and which may be of the same kind as the input beams lasing gas. In response to current therethrough the coil produces an axial magnetic field. The direction of the magnetic field is parallel to the propagation of light transmitted through the dielectric tube. The frequency of the submillimeter wave laser radiation in the tube is shifted from its normal value. The amount of shift is determined by the current in the coil since the resulting magnetic field produces a change in the mean index of refraction of the gas. Thus, the change in index of refraction causes a shift in the laser radiation frequency because the gas within the coil is also located within the submillimeter wave lasing cavity.

Abstract: Phosgene, COCl.sub.2, an impurity in BCl.sub.3 is removed by exposing a BCl.sub.3 mixture containing the impurity to an electrical discharge (i.e., electrical excitation energy level) directed through the mixture. The BCl.sub.3 gas with COCl.sub.2 impurity can be flowing or stationary as desired for a particular process.

Abstract: Laser light is polarized and sent through a low loss rotator. The amount of otation is modulated by a modulator source. The laser light is then sent through a further polarizer where its intensity will be modulated in accordance with the variable rotation imparted upon it.