Ultracompact, ultrashort coherent light sources operating at uv to x-ray wavelengths

A coherent light source device, comprising:

• a magnetic or an electromagnetic undulator structure configured to produce a linearly or helically polarized magnetic or an electromagnetic field having three or more alternating electromagnetic periods and defining an axis within an interaction region;
• a modulation laser source configured to emit one or multiple pulses of linearly or circularly polarized electromagnetic radiation that co-propagate with an electron beam bunch along the axis of the magnetic or electromagnetic undulator within the magnetic or electromagnetic undulator;
• an electron beam source configured to generate the electron beam bunch that traverses the interaction region of the magnetic or electromagnetic undulator along the axis, wherein interaction of the electron beam bunch with the electromagnetic field of the one or multiple pulses of the modulation laser source in the interaction region of the magnetic or electromagnetic undulator structure induces the formation of electron microbunches within the electron beam bunch;
• and
• an undulation laser source configured to emit one or multiple pulses of electromagnetic undulation radiation that traverse the interaction region of the electromagnetic undulator at an interaction angle with respect to the axis, or
• a second magnetic undulator, or
• a dielectric discontinuity,
• wherein interaction of the one or multiple pulses of electromagnetic undulation radiation or the second magnetic undulator or the dielectric discontinuity with the electron microbunches induces spontaneous or stimulated coherent emission of radiation by the electron microbunches at an emission wavelength, wherein the emission wavelength is shorter than a wavelength of the one or more or multiple pulses of electromagnetic undulation radiation or is shorter than the period of the second magnetic undulator or is shorter than the thickness of the dielectric discontinuity.