We report on the experimental observation of abruptly autofocusing waves. This interesting family wave packets has been realized by using a radially symmetric Airy intensity distribution. As demonstrated in our experiments, these waves can exhibit unusual features, such as ability to autofocus following parabolic trajectory toward their focus.

Electron-electron and electron-lattice interactions in noble metals are discussed the light of two-color femtosecond pump-probe measurements silver films. The internal thermalization a nonequilibrium electron distribution created by intraband absorption pump pulse is followed probing induced optical property changes vicinity frequency threshold for d band to Fermi surface transitions. This shown take place with characteristic time constant 350 fs, significantly shorter than previously...

Bulk damage induced by fs IR laser pulses in silica is investigated both experimentally and numerically. In a strong focusing geometry, first zone followed narrow track with submicron width, indicating filamentary propagation. The shape size of the tracks are shown to correspond where electron density created optical field ionization avalanche close 10(20) cm(-3). relative role photoionization studied. plasma produced wake pulse saturate around 2-4x10(20)

We demonstrate the realization of intense Airy-Airy-Airy (${\mathrm{\text{Airy}}}^{3}$) light bullets by combining a spatial Airy beam with an pulse in time. The ${\mathrm{\text{Airy}}}^{3}$ belong to family linear spatiotemporal wave packets that do not require any specific tuning material optical properties for their formation and withstand both diffraction dispersion during propagation. show are robust up high intensity regime, since they capable healing nonlinearly induced distortions profile.

Abstract A review on the recent development of intense laser‐driven terahertz (THz) sources is provided here. The technologies discussed include various types based optical rectification (OR), spintronic emitters, and laser‐filament‐induced plasma. emphasis OR using pump pulses with tilted intensity front. Illustrative examples newly emerging applications are briefly discussed, in particular strong‐field THz control materials acceleration manipulation charged particles.

We experimentally demonstrate, for the first time, an optically implemented blueshift tunable metamaterial in terahertz (THz) regime. The design implies two potential resonance states, and photoconductive semiconductor (silicon) settled critical region plays role of intermediary switching resonator from mode 1 to 2. observed tuning range fabricated device is as high 26% (from 0.76 THz 0.96 THz) through optical control silicon. realization broadband offers opportunities achieving switchable...

Abstract Extreme nonlinear interactions of THz electromagnetic fields with matter are the next frontier in optics. However, reaching this free space is limited by existing lack appropriate powerful sources. Here, we experimentally demonstrate that two-color filamentation femtosecond mid-infrared laser pulses at 3.9 μm allows one to generate ultrashort sub-cycle sub-milijoule energy and conversion efficiency 2.36%, resulting field amplitudes above 100 MV cm −1 . Our numerical simulations...

We present an experimental demonstration and interpretation of ultrafast optically tunable, graphene-based thin film absorption modulator for operation in the THz regime. The component consists a uniform CVD-grown graphene sheet stacked on SU-8 dielectric substrate that is grounded by metallic ground plate. structure shows enhanced originating from constructive interference impinging reflected waves at absorbing sheet. modulation this absorption, which demonstrated via time-domain...

We report self-guided propagation of ultrashort IR laser pulses in fused silica over several Rayleigh lengths. Self-guiding is accompanied by pulse splitting and time compression. Numerical simulations involving self-focusing, temporal dispersion, multiphoton ionization are found to be good agreement with the experimental results. They show that a quasidynamic equilibrium between self-focusing drives filamentation process, while dispersion plays negligible role.

We investigated the spectral behavior of a white-light continuum generated in air by 2-TW femtosecond laser pulses at 800 nm. The spectrum extends least from 300 nm to 4.5 µm. From 1 1.6 µm continuum’s intensity increases strongly with energy and depends on initial chirp.

We report experiments showing the breakup and merging of filaments formed by modulational instability femtosecond optical pulses in air. For input powers as high 25 times self-focusing threshold, beams are shown to split into two spots, which coalesce a self-guided beam. This effect occurs an optically Kerr regime plays important role guiding process. Numerical simulations theoretical estimates both support comparison with experimental data.

Generation and application of energetic, broadband terahertz pulses (bandwidth ~0.1-50 THz) is an active contemporary area research. The main thrust toward the development efficient sources with minimum complexities-a true table-top setup. In this work, we demonstrate generation radiation via ultrashort pulse induced filamentation in liquids-a counterintuitive observation due to their large absorption coefficient regime. generated energy more than order magnitude higher that obtained from...

Tunable-ring Airy beams are experimentally generated and employed for the fabrication of large three-dimensional structures with high resolution using multi-photon polymerization. We demonstrate that these can be adjusted to abruptly autofocus over an extended range working distances while keeping their voxel shape dimensions almost invariant. This striking property together real-time electronically controlled focus tuning makes ideal candidates long-range Moreover, well-controlled remote...

We demonstrate the existence of an additional class stationary accelerating Airy wave forms that exist in presence third-order (Kerr) nonlinearity and nonlinear losses. Numerical simulations experiments, agreement with analytical model, highlight how these solutions sustain evolution beams. The generic nature solution allows extension results to other settings, a variety applications are suggested.

Abstract Laser direct writing is a widely employed technique for 3D, contactless, and fast functionalization of dielectrics. Its success mainly originates from the utilization ultrashort laser pulses, offering an incomparable degree control on produced material modifications. However, challenges remain devising equivalent in crystalline silicon which backbone semiconductor industry. The physical mechanisms inhibiting sufficient energy deposition inside with femtosecond pulses are reviewed...

We report on what is believed to be the first observation of coherent subterahertz (sub-THz) emission from a 1-m string in atmosphere. The sub-THz pulse emitted by filamentary structure an intense IR femtosecond laser detected perpendicularly propagation axis use two heterodyne detectors at 94±1 and 118±1 GHz. describe characteristics this show evidence constructive interference between separate strings.

We report a drastic reduction of air resistivity following the passage self-guided femtosecond pulse from Ti:sapphire laser system at 800 nm with energies per between 1 and 14 mJ duration 120 fs. Connected plasma filaments length that can exceed 150 cm are created by these pulses. The presence conducting channel results multiphoton ionization molecules in filament core.

The filament due to the self-guided propagation of an infrared femtosecond laser pulse in atmospheric-pressure air is used trigger and guide electric discharge. long low density plasma channel first heated by Joule effect during initial transient stage. recombined gas then hydrodynamically expands radially. onset a discharge starts when depression on axis reaches threshold value. This model supported detailed experimental numerical analysis.

Experiments in which several-meter-long infrared ultrashort laser pulses are guided air compared with numerical simulations. During a first self-focusing stage that is affected by modulational instability, the beam shown to break up into two channels of light finally coalesce narrow filament able propagate over several Rayleigh lengths. The propagation associated generation an electron plasma, whose density greater than 1016 cm-3. Electron persists well beyond focal region. simulations...

The nonlinear dynamics of intense truncated Airy beams in Kerr ionizing media are investigated from numerical simulations and experiments. We show numerically that a competition between the linear effects takes place may be modified by tuning width main lobe beam size truncating diaphragm. Our analysis shows acceleration peak, an inherent feature propagation, is preserved only for powers below certain threshold. Nonlinear propagation with low power sustained continuous energy flux its...

We propose a comprehensive physical model explaining the conical character of broadband terahertz generation from femtosecond two-color laser-induced air plasma filaments. show, that, in contrast to other models, emission is always conical, resulting phase matching radiation produced inside filament combined with partial back reflection generated field itself due frequency-dependent critical density. The obtained angle varies 2${}^{\ensuremath{\circ}}$ 10${}^{\ensuremath{\circ}}$, depending...