Proposal for High-harmonic EEHG Lasing at Shanghai Deep Ultra-Violet Free-electron Laser

摘要

The echo-enabled harmonic generation (EEHG) free-electron laser (FEL) hasbeen already demonstrated at lower harmonics and the first lasing at thirdharmonic also has been achieved at Shanghai deep ultra-violet FEL (SDUV-FEL).While the great advantage of much higher harmonic up-conversion efficiency ofEEHG over other seeded FELs only shows evidently at much higher harmonics. Inthis paper, we investigate the possibility of EEHG lasing at 10-th harmonic ofthe seed laser at SDUV-FEL, both physical designs and numerical simulationshave been studied carefully. Two proposals of EEHG at 10-th harmonic have beenstudied respectively, i.e. with the seed lasers of the same color and twodifference colors, the simulation results indicate that both approaches couldbe the candidate for EEHG lasing at 10-th harmonic at SDUV-FEL, meanwhile thecoherent synchrotron radiation does not affect the performance of EEHG-FEL butonly slightly shifts the central radiation frequency.