Nanopatterned electron beams for temporal coherence and deterministic phase control of x-ray free-electron lasers

A light source, comprising:

• an electron photoinjector for producing an electron bunch;
• a first linear accelerator section for accelerating the electron bunch to a relativistic energy;
• a grating for partitioning the electron bunch, downstream of the first linear accelerator section and arranged such that the electron bunch is transmitted through the grating, wherein partitioning the electron bunch is based on the electron spot size at the grating, and wherein:
• the grating comprises a plurality of alternating narrow portions and wide portions,
• the narrow portions have a first thickness in a direction substantially parallel to a direction of propagation of the electron bunch, and
• the wide portions have a second thickness in the direction substantially parallel to the direction of propagation of the electron bunch, the second thickness being greater than the first thickness;
• and
• a light-generating apparatus, downstream of the grating, for generating light from the electron bunch, the light-generating apparatus comprising one or more of the group consisting of:
• an undulator and an inverse Compton scattering laser, wherein a bandwidth of the light is based on the electron spot size, wherein increasing the electron spot size narrows the bandwidth of the pulse of light, and wherein decreasing the electron spot size widens the bandwidth of the pulse of light.