First lasing of a high-gain harmonic generation free- electron laser experiment

Abstract

Abstract-qW e report on the first lasing of a high-gain harmonic generation (HGHG) free-electron laser (FEL). The experiment was conducted at the Accelerator Test Facility (ATF) at Brookhaven National Laboratory (BNL). This is a BNL experiment in collaboration with the Advanced Photon Source (APS) at Argonne National Laboratory. A preliminary measurement gives a high-gain harmonic generation (HGHG) pulse energy that is 2X107 times larger than the spontaneous radiation, In a purely self-amplified spontaneous emission (SASE) mode of operation, the signal was measured as 10 times larger than the spontaneous radiation in the same distance (-2 m) through the same wiggler. This means the HGHG signal is 2X106 times larger than the SASE signal. To obtain the same saturated output power by the SASE process, the radiator would have to be 3 times longer (6 m).

Superradiant and stimulated-superradiant emission of bunched electron beams

“…An entire class by itself comprises the schemes of combined bunching and harmonic emission with seeding ultrafast optical laser beams that we have not covered in depth in this review. The reader is referred to reports on these processes HGHG [120,121], EEHG [122,167,224] and PEHG [223].…”

Coherence of XUV Laser Sources

“…An alternative approach is based on seeding with a laser, see ref. (Yu et al, 1991(Yu et al, , 2000. Such a scheme has been applied at the Deep Ultraviolet FEL (DUV FEL) at the National Synchrotron Light Source (NSLS) of Brookhaven National Laboratory (BNL) (Yu et al, 2003).…”

Soft X-Ray Fel by Cascading Stages of High Gain Harmonic Generation.

“…1, i.e., each stage will consist of one modulator, a dispersion section, and one radiator. The physics process in each stage will be the same as in the recent experiment [20,21]. During the process, the output radiation has disturbed a part of e-beam, which coincides with it.…”

“…In the one stage case, as in the experiment of the references [20,21], Eq. (3A4) may not be satisfied, because we need to impose the limitation V /J < U (the Pierce parameter [2]) in order to ensure the exponential growth in the radiator.…”