Abstract Linearly polarized vector beams are structured lasers whose topology is characterized by a well-defined Poincaré index, which topological invariant during high-order harmonic generation. As such, harmonics produced as extreme-ultraviolet that inherit the of driver. This holds for isotropic targets such noble gases, but analogous behaviour in crystalline solids still open to discussion. Here, we demonstrate this conservation rule breaks solids, virtue their anisotropic non-linear...

High harmonic generation in atomic or molecular targets stands as a robust mechanism to produce coherent ultrashort pulses with controllable polarization the extreme-ultraviolet. However, production of elliptically circularly-polarized harmonics is not straightforward, demanding complex combinations drivers, use alignment techniques. Nevertheless, recent studies show feasibility high-harmonic solids. In contrast atoms and molecules, solids are high-density therefore more efficient radiation...

We study the high-harmonic spectrum emitted by a single-layer graphene, irradiated an ultrashort intense infrared laser pulse. show emergence of typical non-perturbative spectral features, harmonic plateau and cut-off, for mid-infrared driving fields, at fluences below damage threshold. In contrast to previous works, using THz drivings, we demonstrate that cut-off frequency saturates with intensity. Our results are derived from numerical integration time-dependent Schrödinger equation...

Recent studies in high-order harmonic generation (HHG) solid targets reveal new scenarios of extraordinary rich electronic dynamics, comparison to the atomic and molecular cases. For later, main aspects process can be described semiclassically terms electrons that recombine when trajectories revisit parent ion. HHG solids has been by an analogous mechanism, this case involving electron-hole pair recombinations. However, it recently reported a substantial part emission corresponds situations...

We study high-order harmonic generation (HHG) in armchair-type single-wall carbon nanotubes (SWNTs) driven by ultrashort, mid-infrared laser pulses. For a SWNT with chiral indices (n, n), we demonstrate that HHG is dominated bands |m| = n - 1 and the cut-off frequency saturates intensity, as it occurs case of single layer graphene. As consequence, SWNTs can be described effectively one-dimensional periodic system, whose high-frequency emission modified through proper control structural...

The efficiency of high-harmonic generation (HHG) from a macroscopic sample is strongly linked to the proper phase matching contributions microscopic emitters. We develop combined micro+macroscopic theoretical model that allows us distinguish relevance high-order harmonic in single-layer graphene. For Gaussian driving beam, our simulations show relevant HHG emission spatially constrained phase-matched ring around beam axis. This remarkable finding direct consequence non-perturbative behavior...

As an example of how to deal with nonintegrable systems, the nonlinear partial differential equation which describes evolution long surface waves in a convecting fluidis fully analyzed, including symmetries (nonclassical and contact transformatons), similarity reductions application ARS algorithm reductions.As result calculations, Galilean invariance is shown all possible solutions arising from related ODE through these methods are obtained classified terms physical parameters.

Present mass production of large-area single-layer graphene relies fundamentally on chemical vapor deposition methods. The generation grain boundaries, which divides the sample into a set crystalline domains, is inherent to these fabrication Recent studies have demonstrated strong anisotropy in ultrafast non-linear response when subjected non-perturbative, intense laser fields below damage threshold. We propose exploit this characterize size distribution domains polycrystals via high-order...

We report an unexpected result of the anisotropy nonlinear optical response carbon nanotubes, inherent to their chirality. Using a model based on resolution semiconductor Bloch equations, we theoretically demonstrate that, upon irradiation with intense linearly polarized laser pulse along axial direction, chiral nanotubes exhibit oscillating azimuthal current that is absent in achiral species. This induces magnetic field parallel axis nanotube radiates like loop antenna.

Abstract Structured ultrafast laser beams offer unique opportunities to explore the interplay of angular momentum light with matter at femtosecond scale. Linearly polarized vector are paradigmatic examples structured whose topology is characterized by a well-defined Poincaré index. It has been demonstrated that index topological invariant during high-order harmonic generation from isotropic targets, such as noble gases. As result, harmonics produced extreme-ultraviolet same driver. In this...

Graphene has been recently reported to have a damage threshold high enough allow for the interaction with ultrashort laser pulses of intensities above 10¹³ W/cm². It is natural explore if this situation what extend pulse able induce highly non-linear dynamics that gives rise harmonic generation. We perform exact numerical integration set coupled two-level equations describe valence-to-conduction band transitions by pulse, at any point in reciprocal space. analyze...

During the last five years, there has been an increasing interest in generating high-frequency -short wavelength- beams with controllable polarization, due to their potential applications perform ultrafast studies of chiral and/or dichroic systems at nanometer scales. Rather sophisticated configurations have already demonstrated polarization control sub-femtosecond scale through high-order harmonic generation (HHG) atomic gases [1,2]. In parallel, different works recently shown suitability...

Structured laser beams-coherent light beams with nontrivial spatio(temporal) distributions of polarization, phase or intensity-have emerged as unique tools to unravel the electronic dynamics at ultrafast and nanometric scales. A paradigmatic example is high-order harmonic generation (HHG) driven by structured beams, whose deep understanding has triggered emergence a wide variety high-frequency sources topologies that evolve timescales [1]. HHG been mainly studied in atomic molecular gases,...

Understanding high-order harmonic generation (HHG) from solid targets holds the key of potential technological innovations in field high-frequency coherent sources. Solids present optical nonlinearities at lower driving intensities, and harmonics can be efficiently emitted due to increased electron density comparison with atomic molecular counterparts. In addition, crystalline solids introduce a new complexity, as symmetries play role anisotropic character response. An extraordinary...

Structured ultrafast laser beams offer unique opportunities to explore the interplay of angular momentum light with matter at femtosecond scale. Linearly polarized vector are paradigmatic examples structured whose topology is characterized by a well-defined Poincar\'e index. It has been demonstrated that index topological invariant during high-order harmonic generation from isotropic targets, such as noble gases. As result, harmonics produced extreme-ultraviolet beams, same driver. We...

Single layer graphene (SLG) has remarkable physical properties, with potential interest in the fields of electronics and photonics. While being single-atom thick, SLG presents a rather strong optical response, as large absorption, resonance for all excitation frequencies up to vacuum UV and, therefore, broadband linear etc. It been also pointed out that non-linear response THz radiation [1] is particularly strong, nonlinear susceptibilities are found orders magnitude above transparent...

We study the macroscopic build-up of high-harmonic signal in single-layer graphene. Our results show that emission is dominated by a phase-matched ring.

We analyse the high harmonic emission from single-layer graphene driven by infrared vector beams. demonstrate that graphene’s anisotropy offers a privileged scenario to explore non-trivial light spin-orbit couplings, which substantially extends possibilities for generation of high-harmonic structured beams currently studied in atomic and molecular targets. In our case, crystal symmetry introduces spin-dependent diffraction pattern that, coupled with fundamental conservation driver’s...

The development of ultrafast laser pulses is enabling unprecedented studies the electronic dynamics Dirac-Weyl materials subjected to intense fields. In particular, generation high-order harmonics in solid systems emerging as a robust process unveil such through harmonic spectroscopy. general case, high-harmonic (HHG) solids performed finite-gap [1] , [2] which electrons are promoted from valence band conduction tunnel excitation, counterpart ionization gases. However, gapless solids—such...

High-order harmonic generation (HHG) has been demonstrated as a successful technique to produce extreme ultraviolet (XUV) coherent light with controlled spin, or polarization, (SAM) and orbital angular momentum (OAM). For gaseous targets, the composition rules follow from independent simultaneous conservation of each type momenta [1] . However, beams can exchange SAM OAM at nanoscale when propagating through inhomogeneous media [2] Although spin-orbit optical interactions are often regarded...