Proposal for Intense Attosecond Radiation from an X-Ray Free-Electron Laser

Abstract

We propose the use of an ultrarelativistic electron beam interacting with a few-cycle, intense laser pulse and an intense pulse of the coherent x rays to produce a multi-MW intensity, x-ray pulses approximately 100 attoseconds in duration. Because of a naturally occurring frequency chirp, these pulses can be further temporally compressed.

Mode-locked multichromatic x rays in a seeded free-electron laser for single-shot x-ray spectroscopy

“…Finally, it is worth mentioning that several existing schemes [40][41][42][43][44] that use external seeding and a fewcycle infrared laser to generate an isolated attosecond pulse can be extended to generate attosecond pulse train with multiple sharp frequency lines if the few-cycle infrared laser is replaced with an ordinary multiple-cycle laser. For instance, in Ref.…”

LUX: a design study for a linac-/laser-based ultrafast x-ray source

“…In addition to femtosecond-scale pulse durations in LUX, a technique for production of x-ray pulses of approximately 100 attosecond duration has been developed [14]. Access to the sub-femtosecond domain offers great potential of opening a new area of science, studying phenomena on the timescales of electronic transitions [10].…”

“…We have developed a technique for production of attosecond duration x-ray pulses using an optical laser to selectively excite a controlled short section of the electron beam into resonance in the harmonic cascade FEL [14]. Accessing the sub-femtosecond time domain opens new possibilities in experimentally determining dynamics on the timescales of electronic transitions in atoms.…”

Much Ado about Microbunching: Coherent Bunching in High Brightness Electron Beams

“…Current enhanced SASE (eSASE) was proposed as a method to improve peak power, timing, and pulse length control in SASE FELs [39]. The scheme uses an optical laser and dispersive region to seed submicron current spikes in the electron bunch.…”