Evanescent-wave acceleration of ultrashort electron pulses

1998

The possibility of effective electron acceleration in a thin solid film exposed to irradiation by two power ultrashort laser pulses are discussed. The acceleration effect is caused by resonant action of the radiation on electrons oscillating across the film with frequencies close to the laser frequency. The numerical analysis of the relativistic equations of electron motion is conducted.

2011

Physical review letters, 2007

The second-order processes of optical-rectification and photoconduction are well known and widely used to produce ultrafast electromagnetic pulses in the terahertz frequency domain. We present a new form of rectification that relies on the excitation of surface plasmons in metal films deposited on a shallow grating. Multiphoton ionization and ponderomotive acceleration of electrons in the enhanced evanescent field of the surface plasmons results in a femtosecond current surge and emission of terahertz electromagnetic radiation. Using gold, this rectification process is third or higher-order in the incident field.

Optics express, 2014

We study the possibility of surface plasmon polariton (SPP) pulse shape, delay and duration manipulation on sub-picosecond timescales via a high intensity pump SPP pulse photoexciting electrons in a gold film. We present a theoretical model describing this process and show that the pump induces the phase modulation of the probe pulse leading to its compression by about 20% and the variation of the delay between two SPP pulses up to 15 fs for the incident fluence of the pump of 1.5 mJ∙cm⁻².

Physics of Plasmas, 2019

Experiments on the excitation of propagating surface plasmons (SPs) by ultrashort, high intensity laser interaction with grating targets are reviewed. At intensities exceeding 10 19 W cm −2 on target, i.e. in the strongly relativistic regime of electron dynamics, multi-MeV electrons are accelerated by the SP field as dense bunches collimated in a near-tangent direction. By the use of a suitable blazed grating, the bunch charge can be increased up to ≈660 picoCoulomb. Intense XUV high harmonics (HHs) diffracted by the grating are observed when a plasma with sub-micrometer scale is produced at the target surface by a controlled prepulse. When the SP is excited, the HHs are strongly enhanced in a direction quasi-parallel to the electrons. Simulations suggest that the HHs are boosted by nanobunching in the SP field of the electrons which scatter the laser field. Besides the static and dynamic tailoring of the target density profile, further control of electron and HH emission might be achieved by changing the SP duration using a laser pulse with rotating wavefront. This latter technique may allow to produce nearly single-cycle SPs.

Physical Review Letters, 2012

We report a strong, laser-field induced modification of the propagation direction of ultrashort electron pulses emitted from nanometer-sized gold tapers. Angle-resolved kinetic energy spectra of electrons emitted from such tips are recorded using ultrafast near-infrared light pulses of variable wavelength and intensity for excitation. For sufficiently long wavelengths, we observe a pronounced strong-field acceleration of electrons within the field gradient at the taper apex. We find a distinct narrowing of the emission cone angle of the fastest electrons. We ascribe this to the field-induced steering of subcycle electrons as opposed to the diverging emission of quiver electrons. Our findings are corroborated by simulations based on a modified Simpleman model incorporating the curved, vectorial field gradient in the vicinity of the tip. Our results indicate new pathways for designing highly directional nanometer-sized ultrafast electron sources.

Physical Review E, 2011

The generation of ultrastrong attosecond pulses through laser-plasma interactions offers the opportunity to surpass the intensity of any known laboratory radiation source, giving rise to new experimental possibilities, such as quantum electrodynamical tests and matter probing at extremely short scales. Here we demonstrate that a laser irradiated plasma surface can act as an efficient converter from the femto-to the attosecond range, giving a dramatic rise in pulse intensity. Although seemingly similar schemes have been described in the literature, the present setup differs significantly from the previous attempts. We present a model describing the nonlinear process of relativistic laser-plasma interaction. This model, which is applicable to a multitude of phenomena, is shown to be in excellent agreement with particle-in-cell simulations. The model makes it possible to determine a parameter region where the energy conversion from the femto-to the attosecond regime is maximal. Based on the study we propose a concept of laser pulse interaction with a target having a groove-shaped surface, which opens up the potential to exceed an intensity level of 10 26 W/cm 2 and observe effects due to nonlinear quantum electrodynamics with upcoming laser sources.

We report photoelectron emission from the apex of a sharp gold nanotaper illuminated via grating coupling at a distance of 50 μm from the emission site with few-cycle near-infrared laser pulses. We find a fifty-fold increase in electron yield over that for direct apex illumination. Spatial localization of the electron emission to a nanometersized region is demonstrated by point-projection microscopic imaging of a silver nanowire. Our results reveal negligible plasmon-induced electron emission from the taper shaft and thus efficient nanofocusing of few-cycle plasmon wavepackets. This novel, remotely driven emission scheme offers a particularly compact source of ultrashort electron pulses of immediate interest for miniaturized electron microscopy and diffraction schemes with ultrahigh time resolution.

The generation of ultra-strong attosecond pulses through laser-plasma interactions offers the opportunity to surpass the intensity of any known laboratory radiation source, giving rise to new experimental possibilities, such as quantum electrodynamical tests and matter probing at extremely short scales. Here we demonstrate that a laser irradiated plasma surface can act as an efficient converter from the femto- to the attosecond range, giving a dramatic rise in pulse intensity. Although seemingly similar schemes have been presented in the literature, the present setup deviates significantly from previous attempts. We present a new model describing the nonlinear process of relativistic laser-plasma interaction. This model, which is applicable to a multitude of phenomena, is shown to be in excellent agreement with particle-in-cell simulations. We provide, through our model, the necessary details for an experiment to be performed. The possibility to reach intensities above 10^26 W/cm^2,...

Nanophotonics, 2015

The emission of an electron from a metal nanostructure under illumination and its subsequent acceleration in a plasmonic field forms a platform to extend these phenomena to deposited nanoparticles, which can be studied by state-of-the-art confocal microscopy combined with femtosecond optical excitation. The emitted and accelerated electrons leave defect tracks in the immersion oil, which can be revealed by thermoluminescence. These photographic tracks are read out with the confocal microscope and have a maximum length of about 80 μm, which corresponds to a kinetic energy of about 100 keV. This energy is consistent with the energy provided by the intense laser pulse combined with plasmonic local field enhancement. The results are discussed within the context of the rescattering model by which electrons acquire more energy. The visualization of electron tracks originating from plasmonic field enhancement around a gold nanoparticle opens a new way to study with confocal microscopy both...