title: Using irregularly spaced current peaks to generate an isolated attosecond X-ray pulse in free-electron lasers.
abstract: A method is proposed to generate an isolated attosecond X-ray pulse in free-electron lasers, using irregularly spaced current peaks induced in an electron beam through interaction with an intense short-pulse optical laser. In comparison with a similar scheme proposed in a previous paper, the irregular arrangement of current peaks significantly improves the contrast between the main and satellite pulses, enhances the attainable peak power and simplifies the accelerator layout. Three different methods are proposed for this purpose and achievable performances are computed under realistic conditions. Numerical simulations carried out with the best configuration show that an isolated 7.7 keV X-ray pulse with a peak power of 1.7 TW and pulse length of 70 as can be generated. In this particular example, the contrast is improved by two orders of magnitude and the peak power is enhanced by a factor of three, when compared with the previous scheme.
authors: RIKEN SPring-8 Center, Koto 1-1-1, Sayo, Hyogo 679-5148, Japan.
authors: Takashi
authors: T
authors: Tanaka
authors: Physics Group, PAL-XFEL, Pohang Accelerator Laboratory, Pohang 37673, Republic of Korea.
authors: Yong Woon
authors: YW
authors: Parc
authors: RIKEN SPring-8 Center, Koto 1-1-1, Sayo, Hyogo 679-5148, Japan.
authors: Yuichiro
authors: Y
authors: Kida
authors: RIKEN SPring-8 Center, Koto 1-1-1, Sayo, Hyogo 679-5148, Japan.
authors: Ryota
authors: R
authors: Kinjo
authors: Department of Physics, Center for Attosecond Science and Technology, Pohang University of Science and Technology, Pohang, Gyeongbuk 37673, Republic of Korea.
authors: Chi Hyun
authors: CH
authors: Shim
authors: Department of Physics, Center for Attosecond Science and Technology, Pohang University of Science and Technology, Pohang, Gyeongbuk 37673, Republic of Korea.
authors: In Soo
authors: IS
authors: Ko
authors: Max Planck Center for Attosecond Science, Max Planck POSTECH/KOREA Res. Init., Pohang, Gyeongbuk 37673, Republic of Korea.
authors: Byunghoon
authors: B
authors: Kim
authors: Department of Physics, Center for Attosecond Science and Technology, Pohang University of Science and Technology, Pohang, Gyeongbuk 37673, Republic of Korea.
authors: Dong Eon
authors: DE
authors: Kim
authors: Paul Scherrer Insitut, 5232 Villigen PSI, Switzerland.
authors: Eduard
authors: E
authors: Prat
keywords: attosecond pulse; free electron laser; terawatt power level