Extreme Events in Resonant Radiation from Three-dimensional Light Bullets

We report measurements that show extreme events in the statistics of resonant radiation emitted from spatiotemporal light bullets. We trace the origin of these extreme events back to instabilities leading to steep gradients in the temporal profile of the intense light bullet that occur during the initial collapse dynamics. Numerical simulations reproduce the extreme valued statistics of the resonant radiation which are found to be intrinsically linked to the simultaneous occurrence of both temporal and spatial self-focusing dynamics. Small fluctuations in both the input energy and in the spatial phase curvature explain the observed extreme behaviour.Comment: 5 pages, 5 figures, submitte

Soliton-Effect Optical Pulse Compression in Bulk Media with χ^(3) Nonlinearity

Self-compression of visible optical pulse in bulk medium has been demonstrated taking the advantage of negative group-velocity dispersion of tilted pulses

Self-reconstructing spatiotemporal light bullets

We show that spatiotemporal light bullets generated by self-focusing and filamentation of 100 fs, 1.8 μm pulses in a dielectric medium with anomalous group velocity dispersion (sapphire) are extremely robust to external perturbations. We present the experimental results supported by the numerical simulations that demonstrate complete spatiotemporal self-reconstruction of the light bullet after hitting an obstacle, which blocks its intense core carrying the self-compressed pulse, in nonlinear as well as in linear (free-space) propagation regimes

Self-reconstruction of light filaments

By observing how a light filament generated in water reconstructs itself after hitting a beam stopper in the presence and in the absence of a nonlinear medium, we describe the occurrence of an important linear contribution to reconstruction that is associated with the conical nature of the wave. A possible scenario by which conical wave components are generated inside the medium by the distributed stopper or ref lector created by nonlinear losses or plasma is presente

Cavitation dynamics and directional microbubble ejection induced by intense femtosecond laser pulses in liquids

We study cavitation dynamics when focusing ring-shaped femtosecond laser beams in water. This focusing geometry reduces detrimental nonlinear beam distortions and enhances energy deposition within the medium, localized at the focal spot. We observe remarkable postcollapse dynamics of elongated cavitation bubbles with high-speed ejection of microbubbles out of the laser focal region. Bubbles are ejected along the laser axis in both directions (away and towards the laser). The initial shape of the cavitation bubble is also seen to either enhance or completely suppress jet formation during collapse. In the absence of jetting, microbubble ejection occurs orthogonal to the laser propagation axis

Spatial versus temporal deterministic wave breakup of nonlinearly coupled light waves

We investigate experimentally the competition between spatial and temporal breakup due to modulational instability in χ(2) nonlinear mixing. The modulation of the wave packets caused by the energy exchange between fundamental and second-harmonic components is found to be the prevailing trigger mechanism which, according to the relative weight of diffraction and dispersion, leads to the appearance of a multisoliton pattern in the low-dimensional spatial or temporal domain

Spatial versus Temporal Deterministic Wave Breakup of Nonlinearly Coupled Light Waves

We investigate experimentally the competition between spatial and temporal breakup due to modulational instability in χ(2) nonlinear mixing. The modulation of the wave packets caused by the energy exchange between fundamental and second-harmonic components is found to be the prevailing trigger mechanism which, according to the relative weight of diffraction and dispersion, leads to the appearance of a multisoliton pattern in the low-dimensional spatial or temporal domain