IBIC2020 - List of Authors (Wang, X.T.)

Paper	Title	Page
WEPP20	Measurements of Ultraviolet FEL Seed Laser Pulse Width Broading in Thin ß-BBO Crystals	140
	C.L. Li, X.T. Wang, W.Y. Zhang Shanghai Advanced Research Institute, Pudong, Shanghai, People’s Republic of China L. Feng, B. Liu SARI-CAS, Pudong, Shanghai, People’s Republic of China
	Short pulse, high power seed lasers have been implemented to improve the longitudinal coherence and shot-to-shot reproducibility of Free Electron Lasers (FEL). The laser pulse duration is typically 100 - 200 fs with wavelengths in the 260 nm range produced from third harmonic generation of a Ti:sapphire laser. The pulse duration must be measured accurately for seeded FEL operation. The Ultraviolet (UV) pulse width measurement can be carried out with intensity cross-correlation based on the difference frequency generation (DFG) in ultrathin ß-Barium Borate (BBO) crystals. The DFG output pulse broadened due to group velocity mismatch between the 266.7 nm and 800 nm components. The broadening effect depends on the BBO crystal thickness so we explored 0.015 mm, 0.055 mm and 0.1 mm thick samples. To the best of our knowledge, this is the first time that ß-BBO crystal with thickness of only 0.015 mm has been used to measure the UV seed laser pulse width. Experiment results show the measured pulse width broadens with increased BBO thickness in agreement with a theoretical model.
	Poster WEPP20 [1.232 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2020-WEPP20
About •	paper received ※ 01 September 2020 paper accepted ※ 18 September 2020 issue date ※ 30 October 2020
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WEPP25	Photoinjector Driver Laser Temporal Shaping and Diagnostics for Shanghai Soft X-ray Free Electron Laser
	C.L. Li, X.T. Wang, W.Y. Zhang Shanghai Advanced Research Institute, Pudong, Shanghai, People’s Republic of China L. Feng, B. Liu SARI-CAS, Pudong, Shanghai, People’s Republic of China
	It is known that the intensity distribution plays an important role in the electron bunch character, such as its transverse emittance, longitudinal structure. Compared with longitudinal Gaussian distribution, Driver laser pulse with longitudinal flattop structure can produce electron bunch with lower emittance. This paper presents electron beam structure and emittance under different driver laser structure, specifically, laser pulse temporal shaping method for producing Gaussian beam and flattop beam are presented. The advantage and disadvantage of the two method are also discussed. Flattop beam produced from BBO stacking is more benefit for producing electron beam with lower emittance, but significantly increase the microbunch effect. However, Gaussian beam has the advantage to help reducing the mircobunch effect. Moreover, cross correlation method for characterization the laser pulse temporal structure are also presented, particularly, the group velocity mismatch effect induced by the sum frequency BBO crystal are discussed.
	Poster WEPP25 [1.554 MB]
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Measurements of Ultraviolet FEL Seed Laser Pulse Width Broading in Thin ß-BBO Crystals

140

C.L. Li, X.T. Wang, W.Y. Zhang
Shanghai Advanced Research Institute, Pudong, Shanghai, People’s Republic of China
L. Feng, B. Liu
SARI-CAS, Pudong, Shanghai, People’s Republic of China

Short pulse, high power seed lasers have been implemented to improve the longitudinal coherence and shot-to-shot reproducibility of Free Electron Lasers (FEL). The laser pulse duration is typically 100 - 200 fs with wavelengths in the 260 nm range produced from third harmonic generation of a Ti:sapphire laser. The pulse duration must be measured accurately for seeded FEL operation. The Ultraviolet (UV) pulse width measurement can be carried out with intensity cross-correlation based on the difference frequency generation (DFG) in ultrathin ß-Barium Borate (BBO) crystals. The DFG output pulse broadened due to group velocity mismatch between the 266.7 nm and 800 nm components. The broadening effect depends on the BBO crystal thickness so we explored 0.015 mm, 0.055 mm and 0.1 mm thick samples. To the best of our knowledge, this is the first time that ß-BBO crystal with thickness of only 0.015 mm has been used to measure the UV seed laser pulse width. Experiment results show the measured pulse width broadens with increased BBO thickness in agreement with a theoretical model.

Poster WEPP20 [1.232 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2020-WEPP20

About •

paper received ※ 01 September 2020 paper accepted ※ 18 September 2020 issue date ※ 30 October 2020

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPP25

Photoinjector Driver Laser Temporal Shaping and Diagnostics for Shanghai Soft X-ray Free Electron Laser

C.L. Li, X.T. Wang, W.Y. Zhang
Shanghai Advanced Research Institute, Pudong, Shanghai, People’s Republic of China
L. Feng, B. Liu
SARI-CAS, Pudong, Shanghai, People’s Republic of China

It is known that the intensity distribution plays an important role in the electron bunch character, such as its transverse emittance, longitudinal structure. Compared with longitudinal Gaussian distribution, Driver laser pulse with longitudinal flattop structure can produce electron bunch with lower emittance. This paper presents electron beam structure and emittance under different driver laser structure, specifically, laser pulse temporal shaping method for producing Gaussian beam and flattop beam are presented. The advantage and disadvantage of the two method are also discussed. Flattop beam produced from BBO stacking is more benefit for producing electron beam with lower emittance, but significantly increase the microbunch effect. However, Gaussian beam has the advantage to help reducing the mircobunch effect. Moreover, cross correlation method for characterization the laser pulse temporal structure are also presented, particularly, the group velocity mismatch effect induced by the sum frequency BBO crystal are discussed.

Poster WEPP25 [1.554 MB]

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)