Coherent harmonic generation using off-resonance laser modulation based on a laser wakefield accelerator

In this letter, a method using off-resonance laser modulation is proposed for the generation of coherent harmonic radiation. The off-resonant seed laser, whose wavelength is different from the resonant wavelength of the modulator, is firstly used to modulate the angular distribution of electron beam in the modulator. After passing through the special designed dispersion section, strong coherent micro-bunching is imprinted into the e beam which contains high-order harmonic components of the seed laser. The results verify the feasibility of this scheme for the generation of fully coherent radiation in EUV and soft X-ray regimes, which can be well interests of electron beams from a laser wakefield accelerator. © 2019 SPIE.