Spectroscopic Examination of Carbon Dioxide Laser Produced Gas Breakdown.
NAVAL POSTGRADUATE SCHOOL MONTEREY CALIF
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Light from an atmospheric pressure, double-discharge CO2 laser, with a pulse length of 250 nanoseconds and energies from 0.7 to 2.5 joules, was focused in monatomic and diatomic gases at pressures from 1.0 to 8.0 atmospheres in order to produce a plasma for examination. The gases under investigation were Ar, He and N2. Properties of the plasma were determined through analysis of photographs and spectroscopic measurements. Emission spectra in the visible range observed for all gases consisted of an early, intense continuum followed by a lesser continuum superimposed with strong and medium strength lines due to neutral and ionized atoms. Among the more structured lines observed were the argon II lines at wavelengths of 4545A, 4610A, 4765A, 4806A and 4880A. The early continuum lasted for less than 0.5 microseconds, and its appearance coincided with the arrival of the laser beam in the gas chamber. The intensity of the lines varied with wavelength, and rose to maximum intensity at times ranging from 1.6 to 2.2 microseconds after the initial continuum had begun to subside. A method for predicting plasma electron temperatures was also presented.
- Lasers and Masers
- Atomic and Molecular Physics and Spectroscopy
- Plasma Physics and Magnetohydrodynamics