Fisher Andrew, Lenz Maximilian, Ody Alex, Yang Yining, Pennington Chad, Maxson Jared, Hodgetts Tara, Agustsson Ronald, Murokh Alex, Musumeci Pietro
Department of Physics and Astronomy, UCLA, 405 Hilgard Avenue, Los Angeles, CA, USA.
Department of Physics, Cornell University, 616 Thurston Ave., Ithaca, NY, USA.
Nat Commun. 2024 Aug 31;15(1):7582. doi: 10.1038/s41467-024-51892-8.
Free-electron-lasers fill a critical gap in the space of THz-sources as they can reach high average and peak powers with spectral tunability. Using a waveguide in a THz FEL significantly increases the coupling between the relativistic electrons and electromagnetic field enabling large amounts of radiation to be generated in a single passage of electrons through the undulator. In addition to transversely confining the radiation, the dispersive properties of the waveguide critically affect the velocity and slippage of the radiation pulse which determine the central frequency and bandwidth of the generated radiation. In this paper, we characterize the spectral properties of a compact waveguide THz FEL including simultaneous lasing at two different frequencies and demonstrating tuning of the radiation wavelength in the high frequency branch by varying the beam energy and ensuring that the electrons injected into the undulator are prebunched on the scale of the resonant radiation wavelength.
自由电子激光器填补了太赫兹源领域的一个关键空白，因为它们能够实现高平均功率和峰值功率，并具有光谱可调性。在太赫兹自由电子激光器中使用波导可显著增强相对论电子与电磁场之间的耦合，使得电子在通过波荡器单次行程中就能产生大量辐射。除了横向限制辐射外，波导的色散特性对辐射脉冲的速度和滑移有至关重要的影响，而这又决定了所产生辐射的中心频率和带宽。在本文中，我们对紧凑型波导太赫兹自由电子激光器的光谱特性进行了表征，包括在两个不同频率同时激射，并通过改变束流能量以及确保注入波荡器的电子在共振辐射波长尺度上预群聚，来展示高频分支中辐射波长的调谐。
