fullycoherenthardxraygenerationbytwostagephasemergingenhancedharmonicgeneration

Cascading stages of seeded free electron lasers (fels) is a promising way to produce fully coherent x-ray radiation. we study a new approach to produce coherent hard x-rays by cascading the recently proposed phase merging enhanced harmonic generation (pehg) the scheme consists of one dogleg and two pehg configurations, and may be one of the leading candidates for the extracted undulator branch in future x-ray fel facilities. fel physics studies show that such a scheme is feasible within the present technology and can provide high brightness xray radiation pulses with narrow bandwidth and full coherence the radiated peak power at 1 a wavelength converted from an initial 200 nm seed laser is over 2 g