2026-10-10T06:29:20Z https://api.figshare.com/v2/oai

oai:figshare.com:article/33995614 2026-09-25T14:17:11Z category_1 category_915 category_39 category_734 category_69 category_134 portal_63 item_type_2 month_year_09_2026

Time- and Frequency-Domain Study for Electron Beams Penetrating Dielectric Nanospheres: Fingerprints of Cherenkov and Transition Radiation Wenhua Zhao (202003) Christos Tserkezis (1350069) N. Asger Mortensen (1668346) Kurt Busch (1318833) Biophysics Physical Sciences not elsewhere classified Ecology Biological Sciences not elsewhere classified Inorganic Chemistry Virology realistic material model radiative excitation channels main features observed includes material resonances domain framework provides observable cherenkov front discontinuous galerkin time transition radiation transition points thereby revealing thereby facilitating respective contributions primarily responsible low velocities interplay beyond directional decomposition direct view different sophistication based theory We present a theoretical study of Cherenkov and transition radiation for swift electron beams penetrating dielectric nanospheres using material models of different sophistication. Specifically, we perform a combined time-domain (numerically, via the discontinuous Galerkin time-domain method) and frequency-domain (numerically and analytically, via Mie-based theory) study, including the induced-field distribution, cathodoluminescence (CL) multipole/directional decomposition, as well as the time-dependent angular power flow. For low velocities below the Cherenkov threshold, we show that transition radiation is dominant in the far-field CL, and the near-fields at the transition points are primarily responsible for the main features observed in the far-field. For higher velocities far beyond the Cherenkov threshold, we identify the fingerprints of the observable Cherenkov front. Specifically, a constant-permittivity model allows us to isolate the respective contributions of CR and TR to the far-field radiation, thereby facilitating the interpretation of the results for a more realistic material model that includes material resonances. Our combined time- and frequency-domain framework provides a direct view of radiative excitation channels for swift electron beams penetrating dielectric nanoparticles, thereby revealing their interplay beyond the conventional frequency-domain analyses. 2026-09-25T00:00:00Z Dataset Media 10.1021/acsphotonics.6c01605.s001 https://figshare.com/articles/media/Time-_and_Frequency-Domain_Study_for_Electron_Beams_Penetrating_Dielectric_Nanospheres_Fingerprints_of_Cherenkov_and_Transition_Radiation/33995614 CC BY-NC 4.0