{"id":199571,"date":"2021-03-11T16:30:48","date_gmt":"2021-03-11T13:30:48","guid":{"rendered":"https:\/\/en.buradabiliyorum.com\/scientists-propose-novel-self-modulation-scheme-in-seeded-free-electron-lasers\/"},"modified":"2021-03-11T16:30:48","modified_gmt":"2021-03-11T13:30:48","slug":"scientists-propose-novel-self-modulation-scheme-in-seeded-free-electron-lasers","status":"publish","type":"post","link":"https:\/\/buradabiliyorum.com\/en\/scientists-propose-novel-self-modulation-scheme-in-seeded-free-electron-lasers\/","title":{"rendered":"#Scientists propose novel self-modulation scheme in seeded free-electron lasers"},"content":{"rendered":"

“#Scientists propose novel self-modulation scheme in seeded free-electron lasers<\/strong>”<\/p>\n

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\"Scientists
\n The self-modulation scheme together with the electron-beam longitudinal phase spaces at various positions. Credit: SARI
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Seeded free-electron lasers (FELs), which use frequency up-conversion of an external seed laser to improve temporal coherence, are considered ideal for supplying stable, fully coherent, soft X-ray pulses. However, the requirement for an external seed laser with sufficient peak power to modulate the electron beam can hardly be met by the present state-of-the-art laser systems, it remains challenging for seeded FELs to operate at high repetition rate, e.g., MHz repetition rate.<\/p>\n

Motivated by such a challenge, researchers at the Shanghai Advanced Research Institute and the Shanghai Institute of App<\/a>lied Physics of the Chinese Academy of Science<\/a>s reported a novel self-modulation method to enhance laser-induced energy modulation, thereby significantly reducing the requirement of an external laser system.<\/p>\n

Based on the Shanghai soft X-ray FEL test facility, the self-amplification of coherent energy modulation in a seeded FEL is experimentally verified. The peak power requirement of an external seed laser is demonstrated to be relaxed by a factor of 10 to 25 when utilizing the proposed scheme. <\/p>\n

Moreover, the high harmonic generation in a seeded FEL is realized by using an unprecedentedly small energy modulation. A 795 MeV electron beam with a laser-induced energy modulation amplitude as small as 1.8 times the slice energy spread is used for lasing at the 7th harmonic of a 266-nm seed laser in a single-stage high-gain harmonic generation (HGHG) and the 30th harmonic of the seed laser in a two-stage HGHG. <\/p>\n

The results pave a way for a high-repetition-rate seeded FEL, which is expected to show great promise for multidimensional coherent spectroscopies, far beyond what has been demonstrated to date.<\/p>\n

Furthermore, the self-modulation scheme proposed in this work is also promising to solve other critical problems of seeded FELs such as reaching shorter wavelengths and improving stability.<\/p>\n\n

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Researchers propose novel dichroic laser mirror design with mixture layers and sandwich-like-structure interfaces\n <\/p><\/div>\n

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\n More information:<\/strong>
\n Jiawei Yan et al. Self-Amplification of Coherent Energy Modulation in Seeded Free-Electron Lasers, Physical Review Letters<\/i> (2021). DOI: 10.1103\/PhysRevLett.126.084801<\/a><\/p><\/div>\n
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\n Chinese Academy of Sciences
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Citation<\/strong>:
\n Scientists propose novel self-modulation scheme in seeded free-electron lasers (2021, March 11)
\n retrieved 11 March 2021
\n from https:\/\/phys.org\/news<\/a>\/2021-03-scientists-self-modulation-scheme-seeded-free-electron.html<\/p>\n

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\n part may be reproduced without the written permission. The content is provided for information purposes only.<\/p><\/div>\n<\/p><\/div>\n