• Special Issue
  • Special Issue on XFELs
  • 8 Article (s)
Matching-based two-color X-ray free-electron laser generation utilizing laser–plasma accelerated electron beam|On the Cover
Tao Liu, Kaiqing Zhang, Zheng Qi, Si Chen, Chao Feng, Haixiao Deng, Bo Liu, and Dong Wang
Laser–plasma accelerators (LPAs) have great potential to realize a compact X-ray free-electron laser (FEL), which is limited by the beam properties currently. Two-color high-intensity X-ray FEL provides a powerful tool for probing ultrafast dynamic systems. In this paper, we present a simple and feasible method to generate a two-color X-ray FEL pulse based on an LPA beam. In this scheme, time-dependent mismatch along the bunch is generated and manipulated by the designed lattice system, enabling FEL lasing at different wavelength within two undulator sections. The time separation between the two pulses can be precisely adjusted by varying the time-delay chicane. Numerical simulations show that two-color soft X-ray FELs with gigawatt-level peak power and femtosecond duration can be generated, which confirm the validity and feasibility of the scheme.
High Power Laser Science and Engineering
  • Publication Date: Jan. 01, 2022
  • Vol. 10, Issue 1, 010000e1 (2022)
Harmonic-enhanced high-gain harmonic generation for a high repetition rate free-electron laser
Sheng Zhao, Weilun Qin, and Senlin Huang
High Power Laser Science and Engineering
  • Publication Date: Jan. 01, 2022
  • Vol. 10, Issue 1, 010000e4 (2022)
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: Jan. 01, 2021
  • Vol. 9, Issue 4, 04000e51 (2021)
Free electron lasers driven by plasma accelerators: status and near-term prospects
C. Emma, J. Van Tilborg, R. Assmann, S. Barber, A. Cianchi, S. Corde, M. E. Couprie, R. D’Arcy, M. Ferrario, A. F. Habib, B. Hidding, M. J. Hogan, C. B. Schroeder, A. Marinelli, M. Labat, R. Li, J. Liu, A. Loulergue, J. Osterhoff, A. R. Maier, B. W. J. McNeil, and W. Wang
Owing to their ultra-high accelerating gradients, combined with injection inside micrometer-scale accelerating wakefield buckets, plasma-based accelerators hold great potential to drive a new generation of free-electron lasers (FELs). Indeed, the first demonstration of plasma-driven FEL gain was reported recently, representing a major milestone for the field. Several groups around the world are pursuing these novel light sources, with methodology varying in the use of wakefield driver (laser-driven or beam-driven), plasma structure, phase-space manipulation, beamline design, and undulator technology, among others. This paper presents our best attempt to provide a comprehensive overview of the global community efforts towards plasma-based FEL research and development.
High Power Laser Science and Engineering
  • Publication Date: Jan. 01, 2021
  • Vol. 9, Issue 4, 04000e57 (2021)
ReLaX: the Helmholtz International Beamline for Extreme Fields high-intensity short-pulse laser driver for relativistic laser–matter interaction and strong-field science using the high energy density instrument at the European X-ray free electron laser facility
A. Laso Garcia, H. Höppner, A. Pelka, C. Bähtz, E. Brambrink, S. Di Dio Cafiso, J. Dreyer, S. Göde, M. Hassan, T. Kluge, J. Liu, M. Makita, D. Möller, M. Nakatsutsumi, T. R. Preston, G. Priebe, H.-P. Schlenvoigt, J.-P. Schwinkendorf, M. Šmíd, A.-M. Talposi, M. Toncian, U. Zastrau, U. Schramm, T. E. Cowan, and T. Toncian
High-energy and high-intensity lasers are essential for pushing the boundaries of science. Their development has allowed leaps forward in basic research areas, including laser–plasma interaction, high-energy density science, metrology, biology and medical technology. The Helmholtz International Beamline for Extreme Fields user consortium contributes and operates two high-peak-power optical lasers using the high energy density instrument at the European X-ray free electron laser (EuXFEL) facility. These lasers will be used to generate transient extreme states of density and temperature to be probed by the X-ray beam. This paper introduces the ReLaX laser, a short-pulse high-intensity Ti:Sa laser system, and discusses its characteristics as available for user experiments. It will also present the first experimental commissioning results validating its successful integration into the EuXFEL infrastructure and viability as a relativistic-intensity laser driver.
High Power Laser Science and Engineering
  • Publication Date: Jan. 01, 2021
  • Vol. 9, Issue 4, 04000e59 (2021)
The seed laser system of the FERMI free-electron laser: design, performance and near future upgrades
P. Cinquegrana, A. Demidovich, G. Kurdi, I. Nikolov, P. Sigalotti, P. Susnjar, and M. B. Danailov
An important trend in extreme ultraviolet and soft X-ray free-electron laser (FEL) development in recent years has been the use of seeding by an external laser, aimed to improve the coherence and stability of the generated pulses. The high-gain harmonic generation seeding technique was first implemented at FERMI and provided FEL radiation with high coherence as well as intensity and wavelength stability comparable to table-top ultrafast lasers. At FERMI, the seed laser has another very important function: it is the source of external laser pulses used in pump–probe experiments allowing one to achieve a record-low timing jitter. This paper describes the design, performance and operational modes of the FERMI seed laser in both single- and double-cascade schemes. In addition, the planned upgrade of the system to meet the challenges of the upgrade to echo-enabled harmonic generation mode is presented.
High Power Laser Science and Engineering
  • Publication Date: Jan. 01, 2021
  • Vol. 9, Issue 4, 04000e61 (2021)
Coherent optical vortex generation with multiple topological charges based on a seeded free electron laser
Hao Sun, Xiaofan Wang, Chao Feng, Lingjun Tu, Weijie Fan, and Bo Liu
High Power Laser Science and Engineering
  • Publication Date: Jan. 01, 2021
  • Vol. 9, Issue 4, 04000e65 (2021)
Compact and robust supercontinuum generation and post-compression using multiple thin plates
Xinhua Xie, Yunpei Deng, and Steven L. Johnson
We report on compact and robust supercontinuum generation and post-compression using transmission of light through multiple thin solid plates at the SwissFEL X-ray free-electron laser facility. A single stage consisting of three thin plates followed by a chirped mirror compressor achieves compression of initially 30-fs pulses with 800-nm center wavelength to sub-10-fs duration. We also demonstrate a two-stage implementation to compress the pulses further to sub-5-fs duration. With the two-stage setup, the generated supercontinuum includes wavelengths ranging from 500 to 1100 nm. The multi-plate setup is compact, robust, and stable, which makes it ideal for applications at free-electron laser facilities such as pump-probe experiments and laser-arrival timing tools.
High Power Laser Science and Engineering
  • Publication Date: Jan. 01, 2021
  • Vol. 9, Issue 4, 04000e66 (2021)

Original manuscripts are sought to the special issue on X-ray Free Electron Lasers (XFELs) of High Power Laser Science and Engineering (HPL).