Two-beam based two-stage EEHG-FEL for coherent hard X-ray generation

Zhao, Zhentang; Feng, Chao; Chen, Jianhui; Wang, Zhen

doi:10.1007/s11434-016-1060-8

Cited by 18 publications

(6 citation statements)

References 34 publications

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“…We have compared the performances of single-stage HGHG and EEHG at the EUV wavelength and demonstrated highfrequency up-conversion efficiency of EEHG and the insensitivity of EEHG to beam imperfections, marking a great step toward EEHG at soft x-ray wavelengths. Analyses within the framework of idealized models also indicate the possibility of generating coherent radiation pulse at subnanometer wavelengths by combining the EEHG scheme with the fresh bunch techniques [35,36]. This kind of laserlike FEL may enable many new areas of sciences and improve the experimental capabilities when compared to the existing EUV and x-ray light sources.…”

Section: Discussionmentioning

confidence: 98%

Coherent extreme ultraviolet free-electron laser with echo-enabled harmonic generation

Feng

Deng

Zhang

et al. 2019

Phys. Rev. Accel. Beams

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The echo-enabled harmonic generation (EEHG) scheme holds promising prospects for efficiently generating intense coherent radiation at very high harmonics of a conventional ultraviolet seed laser. We report the lasing of the EEHG free-electron laser (FEL) at an extreme ultraviolet (EUV) wavelength with a seeded FEL facility, the Shanghai soft x-ray FEL. For the first time, we have benchmarked the basic theory of EEHG by measuring the bunching factor distributions over one octave down to the EUV region. Our results demonstrated the key advantages of the EEHG FEL, i.e., generation of very high harmonics with a small laser-induced energy spread and insensitivity to beam imperfections, and marks a great step towards fully coherent x rays with the EEHG scheme.

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Section: Discussionmentioning

confidence: 98%

Coherent extreme ultraviolet free-electron laser with echo-enabled harmonic generation

Feng

Deng

Zhang

et al. 2019

Phys. Rev. Accel. Beams

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“…This allows further reductions of the energy modulation A 1 from 2.5 (Yang et al, 2022a) to < 2, not only mitigating the required seed laser powers (Yang et al, 2023) but also reducing the beam heating in the energy spread below 100%. To cover hard X-rays with a photon energy up to 10 keV, one could utilize the cascaded EEHG beamline design with the stage-1 modulator in common, just in case there are space limitations, then construct the rest of the beamline, whereas the CR output from the first stage-2 modulator and radiator pair with harmonic h 1 provides the input seed to the second stage-2 modulator with harmonic h 2 Zhao et al, 2016Zhao et al, , 2017Fan et al, 2022). Hence, the second radiator could potentially generate a very high harmonic regarding the seed laser wavelength 1 of the common stage-1 modulator, e.g.…”

Section: Critical Parameters Determining Eehg Beamlinementioning

confidence: 99%

Toward a fully coherent tender and hard X-ray free-electron laser via cascaded EEHG in fourth-generation synchrotron light sources

Yang,

Yu,

Smaluk

et al. 2023

J Synchrotron Radiat

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Free-electron-laser-based beamlines utilize fully coherent laser pulses with extremely narrow bandwidth allowing direct use of X-rays without monochromators. This could be very beneficial for all users of current and future fourth-generation diffraction-limited synchrotron light sources (DL-SLSs) who need narrowband full-coherence high-brightness X-ray pulses. Based on our previous finding, i.e. that separating the two stages of echo-enabled harmonic generation (EEHG) with a few extra bending-magnet sections provides an effective way to increase the momentum compaction of chicane 1, one can simultaneously achieve adequate prebunching at extremely high harmonics as well as keep the energy modulation to the ideal minimum. This could open the door for cascaded EEHG, toward fully coherent tender and hard X-ray wavelengths. Built on our compact design of a twin-pulse seeding electron beam with an adjustable delay and timing jitter at the level of a few femtoseconds, a cascaded EEHG can be implemented, which includes two EEHG beamlines, where the radiation pulse generated by the first beamline with harmonic h 1 could be used as the input seed laser pulse to the second beamline with harmonic h 2. Hence, the second radiator could potentially reach very high harmonics [h = h 1(20)h 2(25–100)] from 500 to 2000, corresponding to tender and hard X-ray wavelengths. It is demonstrated that the cascaded EEHG scheme is compatible with almost any current or planned fourth-generation DL-SLS, with significant benefits for space-limited storage rings in particular. The main advantage is that this scheme requires almost no change of the storage-ring lattice and is fully compatible with other beamlines. Current proposals for rings with much longer straight sections would add self-amplified spontaneous emission as another viable option for storage-ring-based free-electron lasers.

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“…The use of EEHC to generate shorter-wavelength radiation pulses still requires further experimental confirmation. Multiple stages of EEHG, termed as echo-enabled staged harmonic generation (EESHG) [29][30][31], is another cascade option of EEHG. Although theoretically, EESHG has unrivaled up-frequency conversion efficiency, the complex physical design hinders its practical implementation.…”

Section: Introductionmentioning

confidence: 99%

Ultra-high harmonic conversion of a seeded free-electron laser via harmonic optical klystron

Wang,

Zeng,

Zhang

et al. 2024

Phys. Scr.

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External seeded free-electron lasers (FELs) are compelling tools for generating fully coherent EUV and soft X-ray radiations. Echo-enabled harmonic generation (EEHG), the most typical representative of external seeded FELs, has witnessed a remarkable growth of fully coherent FELs in the last decade, continuously evolving towards higher harmonic conversions and shorter wavelengths. Ultra-high harmonic generation is imperative in the field of FELs. This paper presents a novel method for generating FEL radiation with ultra-high harmonic conversion, utilizing harmonic optical klystron in combination with EEHG. This method can effectively increase the harmonic conversion order to about 90. Theoretical analysis and numerical simulations show that intense and almost fully coherent FEL pulses can be generated with a wavelength of 3 nm. At the same time, the seed laser intensity required by this scheme is lower compared to nominal EEHG, thus facilitating the generation of high-repetition-rate seeded FELs.

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Two-beam based two-stage EEHG-FEL for coherent hard X-ray generation

Cited by 18 publications

References 34 publications

Coherent extreme ultraviolet free-electron laser with echo-enabled harmonic generation

Coherent extreme ultraviolet free-electron laser with echo-enabled harmonic generation

Toward a fully coherent tender and hard X-ray free-electron laser via cascaded EEHG in fourth-generation synchrotron light sources

Ultra-high harmonic conversion of a seeded free-electron laser via harmonic optical klystron

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