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

The technological refinements on high-power laser systems of Petawatt class unveil scenarios for light-matter interaction beyond the laser-plasma perspective. In this contribution we explore the possibility of assisting high-harmonic generation (HHG) with the strong magnetic field associated with one of those intense sources. Recently, there has been an interest in developing schemes to employ intense laser beams to define spatial volumes in which strong magnetic fields are found isolated from the electric field. In this conditions, the magnetic field can be used to assist the harmonic generation from atoms from standard drivers. We demonstrate that, using the proper interaction geometry, the magnetic field confines the transversal dynamics of the con-tinuum electrons allowing, on one side, to enhance the efficiency of the electron rescattering that produces the harmonic radiation and, on the other side, to excite the electron transverse dynamics and to convert this energy into phase-locked harmonic photons of few hundreds of eV. [ABSTRACT FROM AUTHOR]

After more than two decades of attosecond physics, the generation and control of the shortest laser pulses available remains as a complex task. One of the main limitations of reducing the temporal duration of attosecond pulses emitted from high-order harmonic generation (HHG) is the attochirp. In this contribution, we demonstrate that HHG assisted by strong fast oscillating magnetic fields enables the generation of Fourierlimited attosecond pulses in the water window. In short, the magnetic field generates a nanowire-like structure, which transversally confines the electronic wavefunction in the HHG process. We demonstrate that the resulting HHG spectrum extends well beyond the semiclassical cutoff frequency, and most interestingly, it is emitted in the form of few-cycle, Fourier-limited, attosecond pulses. [ABSTRACT FROM AUTHOR]