Figure 1
Survey of filamentation experiments in gas media1,2,3,5,6,7,8,9,10,11,12,13,14,15.
The peak power of laser pulses used for laser-induced filamentation is shown versus the central wavelength of these pulses for experiments performed in the atmospheric air (white circles) and in high-pressure gases (yellow circles): high-pressure N210, Ar at a pressure of 5 bar11, Kr at 4 bar12, Xe at 2.1 bar13, Ar at 4.5 bar14, O2 and N2 at 4.5 bar15. References are given by numbers. Single-filamentation regime in the atmospheric air exists in the dark area of the diagram. Its loosely defined boundaries are shown by gradient shading, with the lower boundary centered at the critical power of self-focusing, Pcr = C(8πn0n2)−1λ2, C ≈ 6.4 and the upper boundary centered at 7Pcr. Above the upper boundary, a laser beam tends to break up into multiple filaments. Continuum of filamentation experiments using Ti: sapphire (TiS) laser systems1,2,3 is shown by the ellipse centered at 800 nm. Other sources of ultrashort pulses for filamentation experiments (shown along the abscissa axis) include Yb: CaF2 laser (Yb), Cr: forsterite laser (CrF), optical parametric amplifier (OPA), optical parametric chirped-pulse amplifier (OPCPA), the second harmonic of a Nd: glass laser (Nd: glass/2) and the second (TiS/2) and third (TiS/3) harmonics of a Ti: sapphire laser output. Filamentation experiments presented in this work are shown by a star. The grey area on the right represents the atmospheric CO2 absorption band.
