The preionized metal vapor jet of a room-temperature metal vapor laser

• Published in: Journal of applied physics Vol. 64; no. 6; pp. 2861 - 2867
• Main Authors: HARVEY, E. C, TOBIN, R. C
• Format: Journal Article
• Language: English
• Published: Woodbury, NY American Institute of Physics 15.09.1988
• Subjects: Exact sciences and technology; Fundamental areas of phenomenology (including applications); Gas lasers including excimer and metal-vapor lasers; Lasers; Optics; Physics; Gas laser; Preionization; Vapor; Steam jet; Metal; Room temperature
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.341597

In the room-temperature metal vapor laser studied, a rapid flow of noble gas entrains sputtered metal atoms, metal ions, and gas ions into the laser discharge volume in the form of a narrow jet. A short rise-time discharge pumps the laser transition and is observed to concentrate onto the preionized metal vapor jet. Radial and axial measurements of the electron temperature and ion number density in the preionized jet have been made using an instantaneous triple probe, and show that the ions are concentrated within the jet and extend up to about 20 cm downstream from the sputtering cell. Electrons are carried along the jet by an axial ambipolar field, and are most energetic at the boundary of the jet where they are heated through three-body recombination. Under certain conditions, flowing gas through the sputtering glow discharge causes the plasma to oscillate with a period of between 2 and 20 μs. These oscillations are due to plasma instabilities associated with the anode glow, and have been eliminated by a suitable arrangement of the discharge electrodes. In so doing the anode glow has been extinguished, the slope resistance of the sputtering discharge reduced, and the performance of the sputtering cell improved.