Resonant-holographic-interferometry for absolute measurements of excimer laser-ablated neutral-atom plume line-density profiles

Conference · Sun Oct 10 04:00:00 EDT 1993 · AIP Conference Proceedings (American Institute of Physics); (United States)

OSTI ID:5228853

Gilgenbach, R M; Lindley, R A; Ching, C H; Lash, J S ^[1]

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1. Intense Energy Beam Interaction Laboratory, Nuclear Engineering Department, University of Michigan, Ann Arbor, Michigan 48109-2104 (United States)

Experiments have been performed to measure Al neutral atom absolute line-density profiles using resonant-holographic-interferometry. The ablation source is a KrF excimer laser with a per-pulse energy of about 0.8 J. Targets are either pure aluminum or Al[sub 2]O[sub 3]. Aluminum ground-state neutral atom line-densities are probed by a dye laser tuned near the 394.401 nm line. A double-pulse interferometry technique is employed in which one pulse includes the laser ablation plume and a second pulse generates reference fringes on a holographic plate by rotating a mirror. Holograms are reconstructed to give interference fringes on film by using a helium-neon laser. Interferograms of laser ablated Al metal give maximum Al neutral plume line-densities in the range of 4-10[times]10[sup 4] cm[sup [minus]2]. Aluminum neutral line-densities from Al[sub 2]O[sub 3] targets are as much as 10-20 times larger than from Al metal targets. The sensitivity of this resonant diagnostic is 4 to 5 orders of magnitude higher than nonresonant neutral-particle interferometry and may be adjusted by tuning the dye laser wavelength shift away from the resonance line. This diagnostic has been demonstrated in vacuum, gas (14 mTorr - 35 Torr) and RF plasma (30 mTorr - 1 Torr) environments. At higher gas pressures, the nonresonant gas-dynamic fringe shift can be subtracted to give the resonant fringe shift and species density.

• OSTI ID: 5228853
• Report Number(s): CONF-9304144--
• Conference Information: Journal Name: AIP Conference Proceedings (American Institute of Physics); (United States) Journal Volume: 288:1
• Country of Publication: United States
• Language: English

Related Subjects

661300* -- Other Aspects of Physical Science-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABLATION
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CHALCOGENIDES
EXCIMER LASERS
GAS LASERS
HOLOGRAPHY
INTERFEROMETRY
LASER-PRODUCED PLASMA
LASERS
OXIDES
OXYGEN COMPOUNDS
PLASMA
PLASMA DIAGNOSTICS