Speaker
Description
Probing structural dynamics at atomic spatial and ultrashort temporal scales reveals unprecedented details of nature’s fundamental behavior, allowing for better understanding of intricate energy-matter interaction occurring at such scales. Ultrafast electron diffraction (UED), is the ideal choice to capture information from atomic-scale initiated by a pump laser and probed by MeV electrons. Moreover, injecting such multi-MeV electron beams from an RF gun with pulse durations and timing jitter both significantly smaller than pump optical pulse width opens new avenues for discovering unprecedented ultrafast phenomena. Laser-generated THz pulses through a titled-pulse-front scheme is a reliable technique to produce THz single cycle pulses of high field intensity. Here, we demonstrate a new design of a dispersion-free parallel-plate standing wave compressor structure that provides focusing of THz pulses to the interaction point therefore strongly modulates the incoming electron bunch energy. The compressor structure is characterized by THz electro-optical sampling (EOS) which provides both the THz spectrum and peak field amplitude at the interaction point. The experimental setup utilizes a compact THz single cycle sources; one is coupled to the structure through a series of parabolic mirrors and another source for the streaking deflector stage. There, the THz is intrinsically time-synchronized with the injected MeV electrons from the RF gun. We show that timing-jitter in the relative time-of-arrival of the compressed MeV electron bunches is reduced compared to uncompressed (elongated) bunches, which enables new frontiers in accessing femtosecond dynamics with UED.
