Light bullets from a femtosecond filament

Abstract

The scenario of the formation of light bullets in the presence of anomalous group velocity dispersion is presented within the same general scenario for condensed matter and humid air. The temporal and spectral parameters of light bullets during filamentation in fused silica and humid air are obtained. A light bullet (LB) is a short-lived formation in a femtosecond filament with a high spatiotemporal light field localization. The sequence formation of the quasi-periodical LB is obtained numerically and is confirmed experimentally by autocorrelation measurements of the LB’s duration. The estimation of the LB duration reaches few-cycle value. It is established that the generation of each LB is accompanied by the ejection of a supercontinuum (SC) in the visible spectrum and an isolated anti-Stokes wing is formed in the visible area of the SC as a result of destructive interference of broadband spectral components. It was found that the energy of a visible SC increases discretely according to the number of LBs in the filament. We demonstrated that the model of ionization in solid dielectric which is used in numerical simulation fundamentally affects the obtained scenario of LB formation. The possibility of the formation of LBs under the filamentation of middle-IR pulses in the atmosphere was shown with numerical simulation.

Ultrafast supercontinuum generation in bulk condensed media

“…Eventually, simultaneous time and space compression was demonstrated to favour a new type of filamentation, which produces quasistationary three-dimensional self-compressed light bullets that preserve a narrow beam diameter and a short pulsewidth over a considerable propagation distance in a nonlinear dispersive medium [81]. To this end, the formation of self-compressed spatiotemporal light bullets was experimentally observed in various nonlinear media, such as fused silica, sapphire and BBO, and under a variety of operating conditions [82][83][84][85][86]. Figure 3(c) shows a numerical example illustrating formation and propagation dynamics of the self-compressed spatiotemporal light bullet in the sapphire crystal, which is accompanied Fig.…”

Regularizing Aperiodic Cycles of Resonant Radiation in Filament Light Bullets

“…[17], another new kind of significantly different filamentation process has been observed in bulk fused silica by pumping into the anomalous dispersion regime. This regime is known to exhibit much more complicated dynamics but also to include the advantage of solitary solutions with full spatiotemporal localization and stationarity, known as light bullets [18][19][20][21][22][23][24][25][26]. In a filament, these conditions cannot be exactly fulfilled [1,2] due to a high number of inherent perturbations [27], but the observations in Ref.…”

Light bullets formation accompanied by odd harmonics generation under Mid-IR femtosecond filamentation in LiF

“…An appearance of new hight-power femtosecond laser sources in MID-IR wavelength region [1] leads to an active research of MID-IR laser filamentation regimes in both, condensed transparent dielectrics [2,3] and gases [4][5][6]. The wavelengths from 2.5 to 4 µm correspond to the anomalous group velocity (GVD) region in a large number if optical materials (silica glass, CaF 2 , BaF 2 , LiF, YAG).…”