Micron-Scale Liquid Films for XUV Generation at the ZEUS Laser Facility

Thin films are essential in many plasma physics experiments, including ion acceleration and high harmonic generation (HHG). Solid thin-film targets, while common, have substantial drawbacks. They generate debris that can damage equipment and require repositioning between shots due to destruction at the interaction site. Liquid thin films offer a self-replenishing alternative, capable of regenerating within milliseconds, thus enabling operation at kHz repetition rates. Using a converging nozzle, we form flat, micron-scale liquid films (“leaves”) suitable for laser plasma interactions. This project aims to characterize and stabilize these liquid targets under vacuum conditions for eventual use in HHG experiments at the NSF ZEUS Laser Facility.

Using reflectance spectra, shadowgraphy, and reflectometry, we characterized the shape, thickness, and surface quality of water leaves at various flow rates through the nozzle. To extend this work, we developed a high-pressure nozzle holder tested up to 3000 PSI, enabling the use of ethylene glycol, a lower vapor pressure liquid with potential to improve pre-plasma conditions.