Advanced Photonics Nexus, Volume. 2, Issue 3, 036004(2023)
High-repetition-rate seeded free-electron laser enhanced by self-modulation On the Cover
Fig. 1. Bunching factor versus energy modulation amplitude
Fig. 2. Schematic layout of the self-modulation HGHG setup. A self-modulation HGHG includes extra dispersive chicane and self-modulator, further amplifying laser-induced energy modulation to obtain a higher harmonic bunching factor.
Fig. 3. The seed laser power ratio of the standard HGHG and self-modulation HGHG in different cases. The blue dot, red cross, and yellow circle correspond to the nominal case of beam size of
Fig. 4. The energy spread ratio of the standard HGHG and self-modulation HGHG in different cases. The blue dot, red cross, and yellow circle correspond to the nominal case of beam size of
Fig. 5. Optimization for the
Fig. 6. Comparison of the FEL performance between self-modulation HGHG (blue) and standard HGHG (red) at the 13th harmonic of the 266-nm seed laser in the cases of different beam sizes. (a), (b) Beam size of
Fig. 7. Optimization of the
Fig. 8. The longitudinal phase space of the electron beam in one seed laser wavelength
Fig. 9. The output FEL performance at the 30th harmonic of the seed laser in the third-harmonic self-modulation. (a) 8.87-nm radiation gain curve in the radiator. (b), (c) The power profile and spectrum after six radiator modules, respectively.
Fig. 10. Bunching factor after the second chicane as a function of the harmonic number in various cases, including without self-modulator and the resonance of the self-modulator tuned at the fundamental wavelength, second, and third harmonic of the seed laser, respectively.
Fig. 11. The typical setup of the SXFEL-TF adopted a cascaded EEHG–HGHG scheme. In the self-modulation experiment, modulator 1, with a period of 80 mm in the first stage EEHG, was used as the first modulator. Chicane 3 is the fresh bunch chicane used as the first chicane. A modulator of the second stage HGHG with a period of 55 mm was the self-modulator. Chicane 4 was regarded as the second chicane. X-band transverse deflection structure (XTDS) section was used to measure the longitudinal phase space of the electron beam.
Fig. 12. The measured intensity of the coherent radiation at various harmonic numbers in the first undulator segment of the radiator, under different
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Hanxiang Yang, Jiawei Yan, Haixiao Deng, "High-repetition-rate seeded free-electron laser enhanced by self-modulation," Adv. Photon. Nexus 2, 036004 (2023)
Category: Research Articles
Received: Dec. 4, 2022
Accepted: Mar. 27, 2023
Published Online: Apr. 19, 2023
The Author Email: Deng Haixiao (denghx@sari.ac.cn)