Article

Self-focusing arrest of femtosecond laser pulses in air at different pressures.

Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzer Strasse 38, D-01187 Dresden, Germany.
Physical Review E (Impact Factor: 2.31). 08/2006; 74(1 Pt 2):016602. DOI: 10.1103/PhysRevE.74.016602
Source: PubMed

ABSTRACT We study analytically and numerically the self-focusing arrest of femtosecond laser pulses in air at different pressures in the presence of an external focus lens. Analytical estimations as well as results of simulations show that the intensity at which the self-focusing arrest occurs is almost independent of the gas pressure. However, a dependence on the temperature is found. The Raman effect is taken into account, and an estimation of the intensity inside of filaments at high altitudes is given.

0 Bookmarks
 · 
27 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The critical power for self-focussing of a femtosecond laser pulse in helium has been measured using the moving focus method. The experimental value is (1 atm) ∼268 GW. Using this value, the nonlinear refractive index is inferred to be ∼ 3.6 × 10-21 cm2/W. In addition, the plots of the electron densities versus energy and pressure have also been used to determine the critical power of helium, based on the intensity clamping of the filamentation process. The value agrees well with the one by the moving focus method.
    Optics Communications 01/2008; · 1.44 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The propagation of high intensity nanosecond UV pulses in air is investigated theoretically and numerically. The stability of localized fundamental and vortex stationary solutions, obtained via Newton’s iterations, are analyzed. Numerical propagation results are provided to corroborate the predicted instabilities of the filament and vortex beams.
    Journal of Optics 04/2013; 15(4):4010-.
  • [Show abstract] [Hide abstract]
    ABSTRACT: X waves are spatiotemporal optical waves with intriguing superluminal and subluminal characteristics. Here we theoretically show that for a given initial carrier frequency of the system localized waves with genuine superluminal or subluminal group velocity can emerge from initial X waves in nonlinear optical systems with normal group velocity dispersion. Moreover, we show that this temporal behavior depends on the wave detuning from the carrier frequency of the system and not on the particular X-wave biconical form. A spatial counterpart of this behavior is also found when initial X waves are boosted in the plane transverse to the direction of propagation, so a fully spatiotemporal motion of localized waves can be observed.
    Physical Review Letters 01/2010; 104(2):023902. · 7.73 Impact Factor