Carrier-envelope phase-stable spatiotemporal light bullets

Abstract

We present an extensive experimental investigation of the self-focusing and filamentation of intense 90 fs, 1.8 μm, carrier-envelope phase-stable laser pulses in fused silica in the anomalous group velocity dispersion region. Spectral measurements in a wedge-shaped sample uncover dynamics of spectral broadening, which captures the evolution of third-harmonic, resonant radiation, and supercontinuum spectra as a function of the propagation distance with unprecedented detail. The relevant events of spectral broadening are linked to the formation and propagation dynamics of spatiotemporal light bullets as measured by a three-dimensional imaging technique. We also show that at a higher input power, the light bullet splits into two bullets, which retain characteristic O-shaped spatiotemporal intensity distributions and propagate with different group velocities. Finally, we demonstrate that the light bullets have a stable carrier-envelope phase that is preserved even after the bullet splitting event, as verified by f-2f interferometric measurements.

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.…”

“…The refocusing event was shown to produce splitting of the light bullet at the secondary nonlinear focus [84], while multiple refocusing cycles were demonstrated to yield the formation of a sequence of quasi-periodical light bullets, each of them resulting in ejection of a new portion of the SC.…”

Regular ‘breathing’ of a near-single-cycle light bullet in mid-IR filament

“…LBs are robust structures and the formation of each LB in the sequence is accompanied by the outburst of certain portion of SC energy in the visible range [10,11]. An important and still poorly investigated aspect of filamentation is related to the compressed wave packet carrier envelope phase-induced effects along the few-cycle pulses propagation in a transparent medium [12,13].…”

Giantically blue-shifted visible light in femtosecond mid-IR filament in fluorides

“…The LB is a stable self-organizing formation that doesn't depend on the wide range of the input pulse parameters. Recently LBs and SC spectrum transformation under variation of nonlinear interaction length of 1800 nm femtosecond pulse in filament have been investigated by focusing laser pulse at the front face of wedge-shaped fused silica sample [18] according to the scheme proposed in [19].…”