Contents
2021
Volume: 9 Issue 4
4 Article(s)

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Research Articles
202 W dual-end-pumped Tm:YLF laser with a VBG as an output coupler
Disheng Wei, Shuyi Mi, Ke Yang, Junhui Li, Jinwen Tang, Baoquan Yao, Tongyu Dai, and Xiaoming Duan
We demonstrated a 202 W Tm:YLF slab laser using a reflecting volume Bragg grating (VBG) as an output coupler at room temperature. Two kinds of active heat dissipation methods were used for the VBG to suppress the shift of wavelength caused by its increasing temperature. The maximum continuous wave (CW) output power of 202 W using the microchannel cooling was obtained under the total incident pump power of 553 W, the corresponding slope efficiency and optical-to-optical conversion efficiency were 39.7% and 36.5%, respectively. The central wavelength was 1908.5 nm with the linewidth (full width at half maximum) of 0.57 nm. Meanwhile, with the laser output increasing from 30 to 202 W, the total shift was about 1.0 nm, and the wavelength was limited to two water absorption lines near 1908 nm. The beam quality factors M2 were measured to be 2.3 and 4.0 in x and y directions at 202 W.
High Power Laser Science and Engineering
  • Publication Date: Oct. 14, 2021
  • Vol.9 Issue, 4 04000e48 (2021)
Recent progress of laboratory astrophysics with intense lasers
Hideaki Takabe, and Yasuhiro Kuramitsu
Thanks to a rapid progress of high-power lasers since the birth of laser by T. H. Maiman in 1960, intense lasers have been developed mainly for studying the scientific feasibility of laser fusion. Inertial confinement fusion with an intense laser has attracted attention as a new future energy source after two oil crises in the 1970s and 1980s. From the beginning, the most challenging physics is known to be the hydrodynamic instability to realize the spherical implosion to achieve more than 1000 times the solid density. Many studies have been performed theoretically and experimentally on the hydrodynamic instability and resultant turbulent mixing of compressible fluids. During such activities in the laboratory, the explosion of supernova SN1987A was observed in the sky on 23 February 1987. The X-ray satellites have revealed that the hydrodynamic instability is a key issue to understand the physics of supernova explosion. After collaboration between laser plasma researchers and astrophysicists, the laboratory astrophysics with intense lasers was proposed and promoted around the end of the 1990s. The original subject was mainly related to hydrodynamic instabilities. However, after two decades of laboratory astrophysics research, we can now find a diversity of research topics. It has been demonstrated theoretically and experimentally that a variety of nonlinear physics of collisionless plasmas can be studied in laser ablation plasmas in the last decade. In the present paper, we shed light on the recent 10 topics studied intensively in laboratory experiments. A brief review is given by citing recent papers. Then, modeling cosmic-ray acceleration with lasers is reviewed in a following session as a special topic to be the future main topic in laboratory astrophysics research.
High Power Laser Science and Engineering
  • Publication Date: Oct. 18, 2021
  • Vol.9 Issue, 4 04000e49 (2021)
Power-scalable sub-100-fs Tm laser at 2.08 μm
Li Wang, Weidong Chen, Yongguang Zhao, Hanlin Yang, Wei Jing, Zhongben Pan, Hui Huang, Jiachen Liu, Ji Eun Bae, Fabian Rotermund, Pavel Loiko, Xavier Mateos, Zhengping Wang, Xinguang Xu, Uwe Griebner, and Valentin Petrov
High Power Laser Science and Engineering
  • Publication Date: Oct. 22, 2021
  • Vol.9 Issue, 4 04000e50 (2021)
Overview of SwissFEL dual-photocathode laser capabilities and perspectives for exotic FEL modes
S. Bettoni, A. Cavalieri, A. Dax, E. Divall, C. P. Hauri, S. Hunziker, M. Huppert, M. Kaiser, M. Paraliev, C. Sydlo, C. Vicario, and A. Trisorio
SwissFEL is a compact, high-brilliance, soft and hard X-ray free electron laser (FEL) facility that started user operation in 2019. The facility is composed of two parallel beam lines seeded by a common linear accelerator (LINAC), and a two-bunch photo-injector. For the injector, an innovative dual-photocathode laser scheme has been developed based on state-of-the-art ytterbium femtosecond laser systems. In this paper, we describe the performance of the SwissFEL photocathode drive lasers (PCDLs), the pulse-shaping capabilities as well as the versatility of the systems, which allow many different modes of operation of SwissFEL. The full control over the SwissFEL electron bunch properties via the unique architecture of the PCDLs will enable in the future the advent of more-advanced FEL modes; these modes include, but are not restricted to, the generation of single or trains of sub-femtosecond FEL pulses, multi-color FEL and finally, the generation of fully coherent X-ray pulses via laser-based seeding.
High Power Laser Science and Engineering
  • Publication Date: Oct. 22, 2021
  • Vol.9 Issue, 4 04000e51 (2021)

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