Byrd J M, Hao Z, Martin M C, Robin D S, Sannibale F, Schoenlein R W, Zholents A A, Zolotorev M S
Ernest Orlando Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, California 94720, USA.
Phys Rev Lett. 2006 Apr 28;96(16):164801. doi: 10.1103/PhysRevLett.96.164801. Epub 2006 Apr 26.
We present a new method to generate steady and tunable, coherent, broadband terahertz radiation from a relativistic electron beam modulated by a femtosecond laser. We have demonstrated this in the electron storage ring at the Advanced Light Source. Interaction of an electron beam with a femtosecond laser pulse copropagating through a wiggler modulates the electron energies within a short slice of the electron bunch with about the same duration of the laser pulse. The bunch develops a longitudinal density perturbation due to the dispersion of electron trajectories, and the resulting hole emits short pulses of temporally and spatially coherent terahertz pulses synchronized to the laser. We present measurements of the intensity and spectra of these pulses. This technique allows tremendous flexibility in shaping the terahertz pulse by appropriate modulation of the laser pulse.
我们提出了一种新方法，可利用飞秒激光调制的相对论电子束产生稳定且可调谐的相干宽带太赫兹辐射。我们已在先进光源的电子储存环中证明了这一点。电子束与通过波荡器共传播的飞秒激光脉冲相互作用，会在电子束团的一小段切片内调制电子能量，其持续时间与激光脉冲大致相同。由于电子轨迹的色散，束团会产生纵向密度扰动，由此产生的空洞会发射与激光同步的时间和空间相干太赫兹脉冲短脉冲。我们展示了这些脉冲的强度和光谱测量结果。通过对激光脉冲进行适当调制，该技术在塑造太赫兹脉冲方面具有极大的灵活性。
