GAIN MEASUREMENTS IN FLOWING $CO_{2}- N_{2}$, $CO_{2}-He, CO_{2}- N_{2}-He$ DISCHARGES
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Date
1970
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Ohio State University
Abstract
Systematic measurements of gain in $CO_{2}$ ($CO_{2}$, $N_{2}$) and ($CO_{2}$, $N_{2}$, He) discharges were made on about thirty individual rotation-vibration lines in the P and R branches of the $00^\circ1-10^\circ0$ transition in $CO_{2}$. The measurements were obtained with different partial pressures of the components in flowing mixtures and for different discharge currents. The source of radiation was a monochromatic $CO_{2}- N_{2}-$He laser working with a power $stabilisation.^{1}$ The absolute power of the laser beam was maintained at its minimum value to avoid all saturation effects. Its diameter was limited by means of two diaphragmes. The laser beam passed through the amplifier tube and was received on a grating spectrometer. The measurement accuracy of gain was of the order of 2% 3%. We have been studying successively: 1) The radial distribution of gain in the amplifier. The curves obtained for different mixtures are in good agreement with the theoretical calculations based on the temperature of gas and on the electron density $distribution.^{2}$ 2) The dependence of the gain upon partial pressures of components in the ($CO_{2}- N_{2}$), ($CO_{2}-He$) and ($CO_{2}- N_{2}-He$) mixtures. These measurements were made for three discharge currents and for each line of the $00^\circ1-10^\circ0$ transition. 3) The optimum gain distribution as a function of the rotational quantum number J. The experimental results obtained for all lines are used to calculate the population of the $00^\circ1$ and $10^\circ0$ levels and the rotational temperature, for some mixtures which provide an optimum gain. The results show that the populations of levels are strongly dependent on the mixture composition. Those obtained for a $CO_{2}- N_{2}-He$ mixture are in good agreement with that of $DJEU.^{3}$
Description
$^{1}$C. Meyer et al., Canadian J. of Phys. 47, 1969, 2565. $^{2}$Gordietz et al., IEEE J. of Quant. Electron, 1968, p. 796. $^{3}$Djeu et al., IEEE J. Quant. Elect. 1968, QE4, p. 256.""
Author Institution: Laboratoire d'Infrarouge, Facult\'{e}A des Sciences de Paris
Author Institution: Laboratoire d'Infrarouge, Facult\'{e}A des Sciences de Paris