Spectral Analysis and Metastable Absorption Measurements of High Pressure Capacitively and Inductively Coupled Radio-Frequency Argon-Helium Discharges
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
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Characterization of the excited state argon population in an argon-helium discharge is of crucial importance to the development of a continuous wave Discharge Assisted Noble Gas Laser. Experiments were conducted in the Richard W. Davis Advanced Laser Facility at AFRL on Kirtland Air Force Base, Albuquerque, NM. During these tests the capability to maintain a capactively-coupled and inductively-coupled radio-frequency discharge at pressures of 300 Torr was demonstrated. Optical Emission Spectroscopy experiments were conducted in order to examine the population distribution of the p-state in argon. The population distributions for these high-pressure and high-power cases were compared to a low-pressure, low-power pure argon discharge to examine the influence of helium on an argon discharge. Tuneable Diode Laser Absorption Spectroscopy experiments were also performed on the inductively coupled discharge to examine the column density of the s5 and s3 metastable states for different discharge parameters. The absorption data was fit to an approximated Voigt profile from which pressure broadening rates of 18 or - 8 MHzTorr and 22 or - 2 MHzTorr were calculated for the 801.48 nm p8 yields s5 and 794.82 nm p4 yields s3 transitions, respectively.
- Plasma Physics and Magnetohydrodynamics