6 results on '"Fenxiang Wu"'
Search Results
2. Investigations of gain redshift in high peak power Ti:sapphire laser systems
- Author
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Wenkai Li, Linpeng Yu, Yuanfeng Wu, Xiao-Ming Lu, Yuxin Leng, Shuai Li, Fenxiang Wu, Cheng Wang, Yanqi Liu, Yi Xu, Zongxin Zhang, and Xiaojun Yang
- Subjects
Materials science ,business.industry ,Amplifier ,Ti:sapphire laser ,Physics::Optics ,Pulse duration ,02 engineering and technology ,Laser ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,Redshift ,Electronic, Optical and Magnetic Materials ,law.invention ,010309 optics ,020210 optoelectronics & photonics ,Narrowband ,law ,0103 physical sciences ,Broadband ,0202 electrical engineering, electronic engineering, information engineering ,Sapphire ,Optoelectronics ,Electrical and Electronic Engineering ,business - Abstract
Gain redshift in high peak power Ti:sapphire laser systems can result in narrowband spectral output and hence lengthen the compressed pulse duration. In order to realize broadband spectral output in 10 PW-class Ti:sapphire lasers, the influence on gain redshift induced by spectral pre-shaping, gain distribution of cascaded amplifiers and Extraction During Pumping (EDP) technique have been investigated. The theoretical and experimental results show that the redshift of output spectrum is sensitive to the spectral pre-shaping and the gain distribution of cascaded amplifiers, while insensitive to the pumping scheme with or without EDP. Moreover, the output spectrum from our future 10 PW Ti:sapphire laser is theoretically analyzed based on the investigations above, which indicates that a Fourier-transform limited (FTL) pulse duration of 21 fs can be achieved just by optimizing the spectral pre-shaping and gain distribution in 10 PW-class Ti:sapphire lasers.
- Published
- 2018
3. Suppression of thermal lens effect in high-pulse-energy Ti:sapphire amplifiers
- Author
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Linpeng Yu, Wenkai Li, Yuxin Leng, Yi Xu, Jun Lu, and Fenxiang Wu
- Subjects
Materials science ,business.industry ,Amplifier ,Ti:sapphire laser ,food and beverages ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,010309 optics ,Optics ,0103 physical sciences ,Thermal ,Sapphire ,Optoelectronics ,Beam expander ,Lens effect ,Electrical and Electronic Engineering ,0210 nano-technology ,business ,Energy (signal processing) ,Beam divergence - Abstract
In high-pulse-energy Ti:sapphire amplifiers with moderate repetition rate, the thermal lens effect can significantly decrease the energy extraction efficiency and increase the risk of optical damage. A new method, without introducing any additional components, is proposed to suppress the thermal lens effect in such amplifiers. By utilizing a particularly designed beam expander before the amplifier, specific expanding ratio and beam divergence can be introduced to the injected seed pulses, which can improve the spatial matching between the seed pulses and the pump pulses, and thus enhance the energy extraction efficiency. The enhancement of the energy extraction efficiency has reached approximately 10% in our experimental four-pass Ti:sapphire amplifier, and the good agreement between theoretical and experimental results also demonstrates the validity and feasibility of this method.
- Published
- 2017
4. Performance improvement of a 200TW/1Hz Ti:sapphire laser for laser wakefield electron accelerator
- Author
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Yujie Peng, Fenxiang Wu, Yanqi Liu, Yi Xu, Penghua Ji, Zhizhan Xu, Xiao-Ming Lu, Zongxin Zhang, Jiabing Hu, Yang Xiaojun, Yuxin Leng, Xingyan Liu, Ruxin Li, Cheng Wang, Gui Jiayan, and Junchi Chen
- Subjects
Diffraction ,Materials science ,business.industry ,Free-electron laser ,Ti:sapphire laser ,Pulse duration ,Particle accelerator ,Electron ,Laser ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,law.invention ,010309 optics ,Optics ,law ,0103 physical sciences ,Sapphire ,Electrical and Electronic Engineering ,010306 general physics ,business - Abstract
For investigations on laser wakefield electron acceleration, there is a strong demand for driving laser exhibiting high stability and good spatial-temporal quality. Here we present an upgraded 200TW/1Hz Ti:sapphire laser with following key characteristics. The fluctuation of pulse energy and beam pointing for consecutive 5400 pulses in 90 min are as low as 0.55% and 1.5μrad respectively. The compressed pulse duration is 23.7 fs, which is about 1.1 times of the Fourier-transform limit. The focal spot obtained by an f/30 off-axis parabolic mirror is 54 μm × 52 μm at 1/e2, which is very close to the diffraction limit. Moreover, in the laser wakefield electron acceleration experiments driven by this upgraded 200TW/1Hz laser, quasi-mono-energetic electron beams are reproduced in consecutive shots. For successive 300 shots, the average peak energy of produced electron beams is 667 MeV, and the peak energy fluctuation is only 3.4%. The progresses on both driving laser and laser wakefield electron acceleration make the realization of compact X-ray free electron laser possible.
- Published
- 2020
5. A Stable 200TW / 1Hz Ti:sapphire laser for driving full coherent XFEL
- Author
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Fenxiang Wu, Yanqi Liu, Yi Xu, Yuxin Leng, Xiao-Ming Lu, Zhaoyang Li, Yanyan Li, Ruxin Li, Jun Lu, Cheng Wang, Zhizhan Xu, and Wenkai Li
- Subjects
Chirped pulse amplification ,Materials science ,business.industry ,Amplifier ,Ti:sapphire laser ,Free-electron laser ,Pulse duration ,Laser ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,law.invention ,010309 optics ,Optics ,law ,0103 physical sciences ,High harmonic generation ,Laser power scaling ,Electrical and Electronic Engineering ,010306 general physics ,business - Abstract
Basic features of the ultra-short Ti:sapphire laser for driving compact X-ray free electron laser (XFEL) seeded by laser-driven high harmonic generation (HHG) at SIOM (Shanghai, China) is presented. The laser system consists of four-stage Ti:sapphire amplifiers and can produce 8 J energy at 1 Hz repetition rate after the final power amplifier. The best shot-to-shot energy fluctuation is as low as 0.54% in rms value, which is a desirable characteristic for driving stable electron acceleration and HHG seed. After compression, maximal pulse energy of 5.6 J and pulse duration of 27 fs can be obtained, the corresponding pulse peak power is above 200 TW. To achieve full coherent XFEL, the amplified chirped laser beam is split into two beams after the final power amplifier. After compression in two independent compressors, the two laser beams can be used to drive laser wakefield acceleration (LWFA) and HHG respectively. The benefit of such a scheme is to improve the timing jitter and achieve all-optical synchronization between the electron beam and HHG seed in the near future.
- Published
- 2016
6. A novel measurement scheme for the radial group delay of large-aperture ultra-short laser pulses
- Author
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Ding Wang, Yujie Peng, Fenxiang Wu, Cheng Wang, Jun Lu, Yuxin Leng, Xiao-Ming Lu, Zhaoyang Li, Yanyan Li, Ruxin Li, Yanqi Liu, Yi Xu, and Wenkai Li
- Subjects
Materials science ,business.industry ,Physics::Optics ,Pulse duration ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Laser ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,law.invention ,Intensity (physics) ,010309 optics ,Lens (optics) ,Optics ,law ,0103 physical sciences ,Femtosecond ,Sapphire ,Beam expander ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry ,0210 nano-technology ,business ,Group delay and phase delay - Abstract
In femtosecond high-peak-power laser system, the radial group delay (RGD) of the pulse front introduced by conventional lens-based beam expanders can significantly decrease the achievable focal intensity, especially when it is larger than the pulse duration. In order to quantitatively analyze and compensate the RGD, a novel measurement scheme based on self-reference and second-order cross-correlation technology is proposed and applied to measure the RGD of the large-aperture ultra-short laser pulses directly. The measured result of the RGD in a 200 TW Ti:sapphire laser system is in good agreement with the theoretical calculation. To our knowledge, it is the first time to realize the direct RGD measurement of large-aperture ultra-short laser pulses.
- Published
- 2016
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