Efficient Longitudinally-shaped Upconversion for Photoinjector-based Particle Accelerators*

With the advent of augmented brightness x-ray free electron lasers (XFELs), such as the LCLS-II, there are ever-increasing requirements on increasing the brightness of electron sources. One avenue to increase the brightness of an XFEL is through reduction of electron beam emittance and energy spread via photoinjector laser shaping[1]. We present a novel method for the simultaneous upconversion and shaping ultraviolet pulses via sum frequency generation. We demonstrate the mixing of two broadband infrared pulses that are efficiently upconverted to narrowband pulses with flat temporal profile as demanded by LCLS-II photoinjector requirements[2]. Additionally, we discuss laser-based spatio-temporal shaping and conditioning of electron beam phase space in order to selectively promote XFEL operational modes.
1. Penco, G., et al. "Experimental demonstration of electron longitudinal-phase-space linearization by shaping the photoinjector laser pulse." Physical Review Letters 112.4 (2014): 044801.
2. Gilevich, Sasha, et al. "The LCLS-II Photo-Injector Drive Laser System." 2020 Conference on Lasers and Electro-Optics (CLEO). IEEE, 2020.