Associate Professor Zhang Dongfang and his research team at Shanghai Jiao Tong University have achieved a remarkable breakthrough in the realm of terahertz surface wave compression technology. The team introduced an innovative electron pulse modulation strategy rooted in 'source compression,' effectively surmounting major technical hurdles associated with compressing low-energy electron pulses. Their research findings have been published in Physical Review Letters, under the article title "Terahertz Surface Wave Compression for Low-Energy Electron Diffraction and Imaging."

In this study, the researchers achieved electron synchronization, acceleration, and compression through the utilization of terahertz surface waves. This resulted in the generation of electron pulses with a pulse width of 74 femtoseconds and a charge of 0.4 femtocoulombs, operating at an accelerating voltage of 1.5 keV. This achievement marks a significant advancement by bringing sub-keV low-energy multi-electron pulses into the femtosecond scale. A notable aspect of this technology is that it eliminates the necessity for a separate compression chamber. Instead, it integrates the functions of electron generation, acceleration, and compression into a single, unified structure, thereby creating a compact and multifunctional electron gun.

Experimental results have confirmed that the compressed electron beam substantially enhances temporal resolution in the ultrafast point projection imaging mode. This development offers a novel tool for investigating physical phenomena, including surface phonons, surface phase transitions, and weak-field detection.