A platform for exploring the influence of pulse-front curvature at the ZEUS laser facility

Laser-driven particle accelerators now look to employ complex or “structured” light to provide improvements in radiation yield, beam quality, energy, and stability. Much of this work remains strictly conceptual given the difficulty in space-time pulse shaping for high-power laser systems, leaving a need for experiments to guide further progress. This presentation provides initial results from a multi-component experimental campaign to explore the role and manipulation of a well-known, low-order pulse spatio-temporal coupling, pulse-front curvature (PFC), in laser-plasma interactions. The campaign includes the development of specialty zero-power chromatic doublets to produce discrete radial delay prior to compression, metrology of the pulse structure, theoretical experimental designs, and preliminary results comparing pulses with ± 0.025 fs/mm² of curvature in driving relativistic electron beams from laser wakefield acceleration on the ZEUS laser. Coupling PFC with spectral-phase delay, we generate tunable chromatic flying-foci to accelerate electrons with intensity peaks of both sub- and super- luminal velocity. Asymmetries in the electron beam spectrum corroborated by numerical simulation provide unique insight into the complex pulse evolution of structured light in a plasma.