Multifilamentation transmission through fog

We have experimentally measured that laser filaments in air generate up to 1014, 3×1012, and 3×1013 molecules of O3, NO, and NO2, respectively. The corresponding local concentrations in the filament active volume are 1016, 3×1014, and 3×1015 cm−3, and allows efficient oxidative chemistry of nitrogen, resulting in concentrations of HNO3 in the parts per million range. The latter forming binary clusters with water, our results provide a plausible pathway for the efficient nucleation recently observed in laser filaments

Section: Production Of Ozone and Nitrogen Oxides By Laser Filamentationmentioning

confidence: 99%

Production of ozone and nitrogen oxides by laser filamentation

Petit¹,

Henin²,

Kasparian³

et al. 2010

“…Notice, moreover, that pulse shaping and closed-loop optimization could also be used to improve the selectivity of multiphoton-excited fluorescence lidar for bioaerosol detection 21 or remote laser induced breakdown spectroscopy 22,23 in the future.…”

Section: ͑1͒mentioning

confidence: 99%

“…In the atmosphere, filaments have been observed up to a few kilometers away from the laser source. 2 They can be generated and propagated even in perturbed conditions such as clouds 3 or turbulence. 4 Their ability to generate a "white-light laser" 5 by self-phase modulation ͑SPM͒ as well as long conducting plasma channels opens the way to atmospheric applications.…”

mentioning

confidence: 99%

“…6 The possibility of controlling to a certain extent the basic features of the propagation of ultrashort laser pulses has been demonstrated recently. Besides the long-known effect of an initial focusing of the beam, 7 the effects of the initial pulse chirp, 2,8-11 spatial filtering, 12 beam profile, 13 pulse energy, 14 initial focus, 15 and polarization 16 have been investigated. However, since numerical simulation of the propagation of high-power, large-diameter laser pulses is time consuming, it is generally not possible to define the best laser conditions to optimize a specific property of the filaments.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Optimal control of filamentation in air

Ackermann

Salmon

Lascoux

et al. 2006

The authors demonstrate optimal control of the propagation of ultrashort, ultraintense (multiterawatt) laser pulses in air over distances up to 36m in a closed-loop scheme. They optimized three spectral ranges within the white-light continuum as well as the ionization efficiency. Optimization results in signal enhancements by typical factors of 2 and 1.4 for the target parameters. The optimization results in shorter pulses by reducing their chirp in the case of white-light continuum generation, while they correct the pulse from its defects and set the filamentation onset near the detector as far as air ionization is concerned

“…They result from a subtle balance between Kerr-lens focusing and defocusing by self-induced plasma. In the atmosphere, filaments have been observed over several hundreds of meters, up to a few kilometers away from the laser source, 7 even in perturbed conditions such as clouds 8 or turbulence. 9 These properties open the way to atmospheric applications, 4 such as LIDAR remote sensing, laser-induced breakdown spectroscopy ͑LIBS͒, lightning control, or free space communications.…”

mentioning

confidence: 99%

Laser noise reduction in air

Béjot

Kasparian

Salmon

et al. 2006

Fluctuations of the white-light supercontinuum produced by ultrashort laser pulses in self-guided filaments ͑spatiotemporal solitons͒ in air are investigated. We demonstrate that correlations exist within the white-light supercontinuum, and that they can be used to significantly reduce the laser intensity noise by filtering the spectrum. More precisely, the fundamental wavelength is anticorrelated with the wings of the continuum, while conjugated wavelength pairs on both sides of the continuum are strongly correlated. Spectral filtering of the continuum reduces the laser intensity noise by 1.2 dB, showing that fluctuations are rejected to the edges of the spectrum.