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Waveform control of terahertz light via electron beam longitudinal phase-space manipulation

Yifan Liang1, Xiaofan Wang1,*, Tong Li2, Jitao Sun1, Zhuoyuan Liu2, Jiayue Yang3, Yong Yu1, Qili Tian2, Zhigang He3 et al.

Hongfei Wang1, Li Zeng1, Hao Sun1, Qinghao Zhu1, Xuan Liu1, Guorong Wu3,†, Weiqing Zhang3,‡, Xueming Yang3, Chuanxiang Tang2, and Lixin Yan2,§

  • *Contact author: wangxf@mail.iasf.ac.cn
  • †Contact author: wugr@dicp.ac.cn
  • ‡Contact author: weiqingzhang@dicp.ac.cn
  • §Contact author: yanlx@mail.tsinghua.edu.cn
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Phys. Rev. Research 8, 023113 – Published 4 May, 2026

DOI: https://doi.org/10.1103/xw7z-5c2d

Abstract

Synthesizing intense terahertz (THz) waveforms with user-defined electric field profiles represents a pivotal challenge for controlling matter at ultrafast timescales. While relativistic electron beams can serve as a versatile source of coherent radiation, conventional schemes lack the ability to deterministically sculpt the temporal structure of the emitted light. Here, we experimentally demonstrate a paradigm for generating tailored THz waveforms by manipulating the longitudinal phase space of the electron beam. By controlling the nonlinear longitudinal correlation of an energy-chirped electron beam, we generate a microbunch train with a chirped density modulation. When coupled to a tapered undulator, this structured beam produces coherent radiation, whose spectral-temporal properties are tunable via adjustment of the undulator taper. Autocorrelation measurements confirm the emission of chirped pulses spanning 8–13 THz, with spectral characteristics that align with simulations of the beam structure. Our approach, establishing a direct link between beam dynamics and light-field synthesis, opens a pathway toward customizable high-field waveforms for advanced coherent control experiments.

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Phys. Rev. Research 8, 023113– Published 4 May, 2026
  • Received 26 November 2025
  • Accepted 11 April 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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