Optical Klystrons and High-Gain Harmonic Generation
Optical klystrons have been in use for decades, and the first use was in an ultraviolet free-electron laser oscillator. An optical klystron (OK) is composed of a modulator wiggler that imposes a velocity modulation on the electrons followed by a magnetic dispersive section that enhances the modulation prior to injection into a radiator wiggler that takes the interaction with the modulation-enhanced electrons to saturation. The magnetic dispersive element is, typically, a three- or four-dipole chicane. The radiator can be tuned to the fundamental or a harmonic of the modulator, in which case the interaction is referred to as high-gain harmonic generation (HGHG). In this chapter, we discuss these concepts and simulations of representative configurations.
KeywordsOptical klystron OK High-gain harmonic generation HGHG Modulator Radiator Magnetic chicane Multistage optical klystron MSOK Harmonic cascade
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