Use of a multicolour laser interferometer for the investigation of pulsed gas discharge

A multicolour multibeam laser interferometer of high sensitivity for the diagonstics of partially ionized plasmas, operating within the limits of one maximum of the transmissivity curve, has been developed. The interferometer operates simultaneously on three wavelengths, viz. 0.63, 1.15 and 3.39 μm, generated by a He-Ne laser. High sensitivity is obtained by the use of an electronic control unit and reaches 10-3 to 10-4 of a fringe. The results of electron density measurements, neutral particle densities and on the electron density profile in pulsed discharges in air and in argon under pressures of 1 to 10 torr are presented. (orig.)