Measurement of Electron Density and Temperature in a Pulsed Argon Ion Laser

Abstract

This paper is concerned with some results of experiment and analysis on plasma of pulsed argon ion laser. A long pulsed discharge was brought about with varied discharge voltages of 2～5kV at pressures from 10 to lOOm Torr. Laser oscillations of 6 argon ion lines were observed in the pressure range from 10 to 30m Torr. The change of electron density during the discharge was measured with a He-Ne laser interferometer and a double probe, giving the value of the order of 10¹4cm⁻³ for the above discharge conditions. The time variation of electron temperature was also determined with a double probe and by the measurement of plasma electrical resistivity. Temperature of 4.5～7×10⁴ °K was obtained. From the analysis of the measured plasma parameters it is concluded that the free fall model of Tonks-Langmuir is valid in the laser plasma except in the early period of the pulsed discharge. Further, observed laser oscillations and spontaneous emissions are analized and three-level model is supported for the pumping of excited levels of argon ion lines in the quasi-CW oscillation region, i.e. the later period, of the laser discharge.