Measurements of intense femtosecond laser pulse propagation in air
- Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 (United States)
The nonlinear self-focusing of an intense femtosecond pulse propagating in air can be balanced by the plasma defocusing as the laser intensity is increased above the threshold for multiphoton ionization. The resultant laser/plasma filament can extend many meters, suitable for many applications such as remote atmospheric breakdown, laser induced electrical discharge, and femtosecond laser material interactions. Direct (bore-sight) measurements of filament size and fluence over 4 m showed a preservation of the total energy in the filament during propagation. This indicates the energy lost in creating the central plasma column through multiphoton ionization was continuously being replenished from the surrounding radiation. Electrical measurement of the filament conductivity estimated the plasma density to be 1x10{sup 16} cm{sup -3} and electrical discharges triggered by a femtosecond laser filament were found to occur at substantially reduced breakdown fields.
- OSTI ID:
- 20736618
- Journal Information:
- Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 5 Vol. 12; ISSN PHPAEN; ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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