Superradiant Smith-Purcell radiation (S-SPR) is a kind of free electron radiation with a train of free electron bunches passing over a periodic grating. In theory, the ultra-narrow spectral ...

Based on PIS-SPR, the free electron beam is well bunched and ultra-narrow spectral linewidth at THz frequency region has been observed. Credit: eLight (2025). DOI: 10.1186/s43593-025-00083-z ...