The Quantum X-ray Compton Free Electron Laser

The quantum operation mode in the X-ray Compton free-electron laser (FEL) is presented. This FEL mode emerges when the quantum emission exceeds the electron beam energy spread and FEL homogeneous linewidth, determined by the optical undulator length. Such a FEL becomes a two-level quantum oscillator with a completely inverted active medium. In the nonlinear interaction regime, inversion can be completely removed in a single pass, in analogy with πpulse formation in coherently amplifying medium. Estimates show the quantum FEL provides a promising compact high-power high-brightness source of coherent x-ray radiation. The design parameters for the quantum FEL are proposed for a compact high brightness coherent X-ray radiation source