SLAC, Menlo Park, California, USA
UCB, Berkeley, USA
SLAC, Menlo Park, California, USA
Colorado School of Mines, Golden, USA
Temporal shaping of photocathode excitation laser pulses is a long-sought-after challenge to tailor the phase-space of electrons. The temporal profile of lasers, typically up-converted from infrared to ultraviolet, have significant impact on the distribution and time-evolution of the collective electron bunches. Towards this end, we present a method combining efficient nonlinear up-conversion with simultaneous and adaptable temporal profile shaping through dispersion-controlled sum-frequency generation* resulting in temporal profiles with sharp rise-fall times and flat top profiles. Using the LCLS-II photoinjector as a case study, we demonstrate a reduction in generated electron transverse emittance by upwards of 30% over conventionally implemented temporal profiles. Additionally, we discuss the ongoing experimental implementation of this method and preliminary results.
* R. Lemons, et al. arXiv:2012.00957 [physics.optics] (2020)
BNL, Upton, New York, USA
We propose a novel architecture for a mid-IR, high-repetition, kilowatt-class, CO2 laser system operating in a pulse-burst regime and its implementation in In-verse Compton Scattering (ICS) sources of x-ray and gamma-ray radiation. Different types of particle accelerators are considered for conversion to such ICS sources, including energy recovery linacs and synchrotron storage rings. The expected ICS performance parameters are compared with earlier proposals where CBETA and DAΦNE accelerators have been paired with near-IR, mode-locked solid-state lasers operating at a multi-megahertz repetition rate. A considerable increase in acting laser energy attainable in our CO2 laser-based scheme, combined with an order of magnitude higher number of laser photons per Joule of energy allows maintaining a similarly high average flux of produced hard x-rays while the peak flux and brilliance will be raised by three to four orders of magnitude compared to aforementioned schemes based on near-IR lasers.
KIT, Karlsruhe, Germany
PSI, Villigen PSI, Switzerland
Universität Bern, Institute of Applied Physics, Bern, Switzerland
A compact, longitudinal diagnostics for fs-scale electron bunches using a THz electric-field transient in a split-ring resonator (SRR) for streaking will be tested at the Ferninfrarot Linac- Und Test- Experiment (FLUTE). For this new streaking technique, intensive THz pulses are required, which will be generated by laser-based optical rectification. We present a setup for generating THz pulses using tilted-pulse-front pumping in lithium niobate at room temperature. Excited by an 800 nm Ti:Sa pump laser with 35 fs bandwidth-limited pulse length, conversion efficiencies up to 0.027% were achieved. Furthermore, the status of the SRR experiment is shown.