Field propagation-induced directionality of carrier-envelope phase-controlled photoemission from nanospheres

Abstract

Near-fields of non-resonantly laser-excited nanostructures enable strong localization of ultrashort light fields and have opened novel routes to fundamentally modify and control electronic strong-field processes. Harnessing spatiotemporally tunable near-fields for the steering of sub-cycle electron dynamics may enable ultrafast optoelectronic devices and unprecedented control in the generation of attosecond electron and photon pulses. Here we utilize unsupported sub-wavelength dielectric nanospheres to generate near-fields with adjustable structure and study the resulting strong-field dynamics via photoelectron imaging. We demonstrate field propagation-induced tunability of the emission direction of fast recollision electrons up to a regime, where nonlinear charge interaction effects become dominant in the acceleration process. Our analysis supports that the timing of the recollision process remains controllable with attosecond resolution by the carrier-envelope phase, indicating the possibility to expand near-field-mediated control far into the realm of high-field phenomena.

Attosecond-controlled photoemission from metal nanowire tips in the few-electron regime

“…This is in agreement with experiments on plasmonic nanofilms 47 but different from results for the multi-electron emission from nanoparticles, where charge interaction leads to an extension of the cutoff to higher energies and additionally, as discussed below, a suppression of the low-energy peak in the electron kinetic energy spectrum. 23,24 The asymmetry data also allow us to obtain information about the electron dynamics. In the gas measurements in Fig.…”

“…23,24,46 There, the electron emission leads to the creation of a positive charge localized at the surface, creating a trapping potential from which direct electrons cannot escape due to their low kinetic energy. Consequently, direct electrons are completely suppressed and there is a relatively clear asymmetry also at lower kinetic energies.…”

“…We detect several electrons per laser shot. Our experiments cover the range between previous CEP-resolved photoemission experiments on metal nanotips 20,21 (singleelectron regime) and on nanospheres 23,24 (many-electron regime), where in the latter case the electron dynamics is strongly dominated by the interaction between electrons and between ions and electrons. Charge interaction effects in CEP-resolved photoemission have also been studied theoretically for metal nanotips.…”

Nanofocusing, shadowing, and electron mean free path in the photoemission from aerosol droplets

“…Ziemann and McMurry performed secondary electron yield measurements for probing organic films on aerosol particles [4] and recently Su et al used photoelectron spectroscopy to study solvation phenomena in droplets [5]. Plasma formation in clusters and different types of particles after exposure to intense femtosecond pulses was observed through mass spectrometry and ion imaging [6,7], while electron imaging was used to study directional emission from dielectric particles using intense few-cycle laser fields [8,9].…”

Luminescent tracks of high-energy photoemitted electrons accelerated by plasmonic fields

“…When ≪ 1, the emission is caused by tunnelling after the electron is accelerated by the optical field. The photoelectrons originating from the metal or dielectric [17,18] nanostructures follow a quivering motion in the oscillating electromagnetic field and thereby acquire energy. The energy of this electron, also called the ponderomotive potential energy, is determined by the quiver motion in the driving field with a value of Up = e 2 F 2 /4mω 2 .…”