Intensity clamping measurement of laser filaments in air at 400 and 800 nm

Journal Article · Sun Aug 15 04:00:00 EDT 2010 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.82.023405· OSTI ID:21448522

Daigle, J -F; Hosseini, S; Wang, T -J; Kamali, Y; Chin, S L ^[1]; Jaron-Becker, A; Becker, A ^[2]; Roy, G ^[3]

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1. Centre d'Optique, Photonique et Laser (COPL) and Departement de Physique, de Genie Physique et d'Optique, Universite Laval, Quebec, Quebec G1V 0A6 (Canada)
2. JILA and Department of Physics, University of Colorado, Boulder, Colorado 80309-0440 (United States)
3. Defence Research and Development Canada-Valcartier, 2459 Pie-XI Boulevard North, Quebec, Quebec G3J 1X5 (Canada)

Molecular N{sub 2} fluorescence excited by laser filaments formed from laser pulses at 400 and 800 nm propagating in air is investigated. A comparison showed that, when excited with 400 nm photons, the fluorescence from the first negative band of N{sub 2}{sup +} was enhanced by a factor of 6.4 while that of the second positive band of neutral N{sub 2} remained relatively constant. The enhanced N{sub 2}{sup +} signal is attributed to a more efficient inner-shell multiphoton process (to the B{sup 2{Sigma}}{sub u}{sup +} state) at 400 nm leaving a larger population of N{sub 2}{sup +} ions in the excited state. On the other hand, the stable fluorescence from neutral N{sub 2} is due to the fact that the plasma density is more or less the same at both wavelengths. Using these results, a theoretical model is developed to determine the clamped intensities of the laser filaments at 400 and 800 nm.

• OSTI ID: 21448522
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 2 Vol. 82; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
74 ATOMIC AND MOLECULAR PHYSICS
AIR
BOSONS
CHARGED PARTICLES
COLLISIONS
COMPARATIVE EVALUATIONS
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
ELEMENTS
EMISSION
EVALUATION
FILAMENTS
FLUIDS
FLUORESCENCE
GASES
IONS
LASER RADIATION
LASER-PRODUCED PLASMA
LUMINESCENCE
MASSLESS PARTICLES
MOLECULAR IONS
MOLECULE COLLISIONS
MOLECULES
MULTI-PHOTON PROCESSES
NITROGEN
NITROGEN IONS
NONMETALS
PHOTON COLLISIONS
PHOTON EMISSION
PHOTON-MOLECULE COLLISIONS
PHOTONS
PLASMA
PLASMA DENSITY
PULSES
RADIATIONS