Chiral Smith–Purcell Radiation Light Source

摘要

Smith–Purcell radiation (SPR) with broadly tunable spectra has attractedattention in light emission, and this free-electron-driven source shows greatpotential in illumination fields, such as terahertz sources, ultra-compact lightsources, free-electron lasers, etc. However, it remains difficult to control thepolarization properties of SPR and realize a free-electron chiral light source. Inthis work, the chiral SPR with the maximum chirality (>40) is acquired in aperiodic stacked nanosquare light-well, and the radiation chirality ismanipulated by variations of the designed electron beam excitation positions.Furthermore, this work reveals that the chiroptical effect originates in thesuperposition of SPRs with different phases and polarization, which arederived from adjacent sidewalls. This work may deepen the comprehension ofelectron-matter interaction and facilitate the development of compactelectron-driven chirality-tunable source-on-chip, highlighting potentialapplications in photonic integration and binary data processing.