Stimulated Smith-Purcell emission based on bound states in the continuum

Smith-Purcell radiation from a charge moving above a finite-length grating with rectangular profiles

Smith-Purcell radiation is generated by a charged particle beam passing close to the surface of a diffraction grating which has a strong dependency of the emitted radiation intensity on the form of the grating profile. For relativistic electron beam, it is important to take into account the number of grating periods in practical SPR setups. In this paper, the theoretical investigations of Smith-Purcell radiation from a three-dimensional bunch of relativistic electrons that moves at constant speed parallel to an electrically perfectly conducting grating with finite rectangular grooves are carri…

Generation of Accelerating Waves in Smith-Purcell Radiation

Metasurface has recently emerged as a powerful platform to engineer wave packets of free electron radiation at the mesoscale. Here, we propose that accelerating waves can be generated when moving electrons interact with an array of bianisotropic meta-atoms. By changing the intrinsic coupling strength, we show full amplitude coverage and 0-to-π phase switching of Smith-Purcell radiation from bianistropic meta-atoms. This unusual property leads to the creation of Airy beams that shifts along a parabolic trajectory during propagation. Experimental implementation displays that evanescent fields bo…

通过对称性破缺观测固有手性史密斯-珀塞尔效应

Observation of the Inherent Chiral Smith-Purcell Effect via Symmetry Breaking

利用非手性非共振硅光栅，通过电子诱导倏逝波的横向自旋角动量转换为纵向形式，实现了宽带可调谐的高手性史密斯-珀塞尔辐射，偏振度达0.87。

Boosting the efficiency of Smith-Purcell radiators using nanophotonic inverse design

The generation of radiation from free electrons passing a grating, known as Smith-Purcell radiation, finds various applications including non-destructive beam diagnostics and tunable light sources, ranging from terahertz towards X-rays. So far, the gratings used for this purpose have been designed manually, based on human intuition and simple geometric shapes. Here we apply the computer-based technique of nanophotonic inverse design to build a 1400nm Smith-Purcell radiator for sub-relativistic 30 keV electrons. We demonstrate that the resulting silicon nanostructure radiates with a 3-times-hig…

时间光栅产生的史密斯-珀塞尔辐射

Smith-Purcell radiation from time grating

本文提出时间光栅产生的时间史密斯-珀塞尔辐射（t-SPR），并给出广义色散方程，通过时间调制实现辐射操控、增强鲁棒性并放大发射。

Free-electron-light interactions in nanophotonics

When impinging on optical structures or passing in their vicinity, free electrons can spontaneously emit electromagnetic radiation, a phenomenon generally known as cathodoluminescence. Free-electron radiation comes in many guises: Cherenkov, transition, and Smith-Purcell radiation, but also electron scintillation, commonly referred to as incoherent cathodoluminescence. While those effects have been at the heart of many fundamental discoveries and technological developments in high-energy physics in the past century, their recent demonstration in photonic and nanophotonic systems has attracted …