Energy threshold for laser induced breakdown on a metal surface under high and ultra high vacuum conditions.
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Authors
Gedik, Abdullah
Subjects
Laser induced breakdown
Plasma onset
Unipolar Arcing
Cascaded breakdown
Multi photon ionization
Thermal runaway
Plasma onset
Unipolar Arcing
Cascaded breakdown
Multi photon ionization
Thermal runaway
Advisors
Schwirzke, F.
Date of Issue
1991-06
Date
Publisher
Monterey, California. Naval Postgraduate School
Language
en_US
Abstract
Unipolar arcing is the primary breakdown process when a powerful laser pulse interacts with
a target surface. The unipolar arc model assumes that the initial ionization occurs in desorbed
gas layers. To check this experimentally a metal surface was illuminated under different vacuum
conditions. The experiments were conducted at 10"4
,
10"6
, and 10 8
torr vacuum. A
neodymium:glass laser of wavelength 1.06 urn in the Q-switched mode was utilized. Type 304,
polished, stainless steel plates were used as targets. Results confirmed that higher laser energy
was needed to trigger the laser induced breakdown at lower pressures.
Type
Thesis
Description
Series/Report No
Department
Physics
Organization
Naval Postgraduate School
Identifiers
NPS Report Number
Sponsors
Funder
Format
32 p.;28 cm.
Citation
Distribution Statement
Approved for public release; distribution is unlimited.