Towards Multi-Petawatt, Renewable Plasma Mirrors Using Ultrathin Films of Liquid Crystal Mixtures

We describe a new approach for making plasma mirrors (PMs) for multi-petawatt (PW) lasers using ultrathin (~25 nm), large diameter (10 mm – 24 mm) films of liquid crystal (LC) mixtures. PMs play a vital role in pulse contrast enhancement and beam redirection of high-power, ultrashort pulse lasers.[1] For multi-PW systems, they are also indispensable for the protection of upstream optics. PMs have an optimal peak-intensity at which they trigger necessitating ever larger optics for increasing pulse energy and PM operation is destructive, requiring rapid insertion of a new PM on every laser shot. We present a system for inserting free standing LC films on demand after each laser shot that can serve as PMs in sophisticated beamlines up to 4 PW. Critical to this project was achieving good optical quality over a large enough area to support the pulse energy. The use of LC mixtures permitted tuning of the film properties to optimize performance.

[1] N. Czapla, et al., Sci. Rep. 15, 21115 (2025). DOI: 10.1038/s41598-025-07016-3