All-optical spatio-temporal control of electron emission from isolated dielectric nanospheres with two-color laser pulses

Field localization by nanostructures illuminated with laser pulses of well-defined waveform enables spatial-temporal tailoring of the near-fields for sub-cycle control of electron dynamics at the nanoscale [1]. Transition from the ponderomotive to sub-cycle acceleration regime of the near-field-driven electron emission was shown to be determined by the ratio of the near-field decay length and amplitude of the electron quiver motion [2]. Field-propagation-induced shaping of the near-field in turn has been utilized for size-dependent directional tuning of the electron emission from isolated nanospheres [3]. Here, we go beyond these studies and use intense 30 fs two-color laser pulses (780 nm/390 nm) to tailor the spatio-temporal near-fields of SiO2 nanoparticles, enabling the all-optical control of the electron emission direction.