Isolated few-cycle radiation from chirped-pulse compression of a superradiant free-electron laser

Abstract

When a short electron bunch traverses an undulator to radiate a wavelength longer than the bunch length, intense superradiance from the electron bunch can quickly deplete the electron's kinetic energy and lead to generation of an isolated chirped radiation pulse. Here, we develop a theory to describe this novel chirped pulse radiation in a superradiant free-electron laser and show the opportunity to generate isolated few-cycle high-power radiation through chirped-pulse compression after the undulator. The theory is completely characterized by how fast the electron energy is depleted for a given length of an undulator. We further present two design examples at the THz and extreme-ultraviolet wavelengths and numerically generate isolated three-and nine-cycle radiation pulses, respectively.

Superradiant and stimulated-superradiant emission of bunched electron beams

“…This current contains an infinite number of harmonics, but we assume here that only one harmonic at ω 0 = nω b is interacting synchronously with the wave, so that we need to keep in (C19) only ñn (r) and ñ−n (r) = ñ * n (r). Equating (C9) in the phasor representation(52): n(r, t) ≡ Re{ñ(r)e −iω 0 t } = so that it can be applied to a general wiggler: uniform or tapered, planar or helical, we write the perpendicular velocity of the wiggler asv ⊥ = Re{ṽ w (z)e i z 0 kw(z )dz } = 1 2 ṽw (z)e i z 0 kw(z )dz + c.c.,(C24)and define the perpendicular current density asJ ⊥ = −env ⊥ = Re{ J⊥ e −iω 0 t }. ṽ * w (z)e −i z 0 kw(z )dz ,(C26)and using Eq.…”

Dielectric Laser Accelerators: Designs, Experiments, and Applications

“…A coherent light source was an early proposed application of microstructure accelerators [166]. Other ideas have been developed taking advantage of the unique attosecond bunch format produced by DLAs [167,168].…”