Trapping field assisted backscattering in strong-field photoemission from dielectric nanospheres

We study strong-field ionization of dielectric nanospheres and focus on the enhancement of the cut-off energies for backscattering electrons resulting from charge interaction. Though recent studies clearly demonstrated the decisive impact of a surface trapping field on the electron backscattering process, a clear picture of the underlying mechanism is lacking. Here, we provide this picture and present a simple and transparent extension of the...