Demonstration of a widely-tunable and fully-coherent high-gain harmonic-generation free-electron laser
Demonstration of a widely-tunable and fully-coherent high-gain harmonic-generation free-electron laser
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宽可调、全相干高增益谐波产生自由电子激光器的演示
DOI：
10.1103/physrevstab.16.020704
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发表时间：
2013-02-19
影响因子：
--
通讯作者：
Zhao, Z. T.
中科院分区：
文献类型：
--
作者：
Liu, B.;Li, W. B.;Zhao, Z. T.
自由电子激光器（FELs）是第四代光源，可以在从远红外到硬x射线的宽波长范围内提供极高强度的超短光脉冲。基于自放大自发发射原理的激光器已成功运行，具有超高亮度和宽波长调谐范围，横向相干性好，但时间相干性差。相比之下，激光种子激光器提供了充分的相干性，但在选定的中心波长，通常是激光种子的谐波，具有相对较窄的调谐范围。我们报告了一种高增益谐波产生（HGHG） FEL的实验演示，该FEL使用光学参数放大，变间隙波动器和谐波选择的组合在大范围内连续可调，其中时间相干性被迈克尔逊干涉术证实。为了获得更高的光子能量，本文还在上海深紫外自由电子激光试验装置上进行了新鲜束技术级联HGHG的首次尝试。DOI: 10.1103 / PhysRevSTAB.16.020704
Free-electron lasers (FELs) are fourth-generation light sources that deliver extremely high intensity, ultrashort light pulses over a broad wavelength range from far-infrared to hard x ray. FELs based on the self-amplified spontaneous emission principle have been successfully operated with ultrahigh brightness and a broad wavelengths tuning range with good transverse coherence but poor temporal coherence. In contrast, the laser-seeded FELs have provided full coherence but at selected central wavelengths, usually the harmonics of the laser seeds, with relatively narrower tuning range. We report the experimental demonstration of a high-gain harmonic-generation (HGHG) FEL that is continuously tunable over a wide range using the combination of optical parametrical amplification, variable-gap undulator, and harmonic selection, where the temporal coherence is preserved as confirmed with the Michelson interferometry. In order to achieve higher photon energies, the first try of cascaded HGHG with a fresh-bunch technique is also made at the Shanghai Deep Ultraviolet Free-electron Laser test facility. DOI: 10.1103/PhysRevSTAB.16.020704