Renewable plasma mirrors for multi-petawatt lasers using free standing films made from liquid crystal mixtures

We describe new advances in the development of making ultrathin, freestanding films of liquid crystal for use as plasma mirrors for ultrashort pulse, high power lasers. Such lasers are a vital part of the study of high energy density science which is important both for fundamental research and possible applications in industry and medicine. Plasma mirrors are vital both for pulse constant enhancement and for dynamic beam redirection in advanced beamlines. Plasma mirrors based on liquid crystal have some advantages over conventional technology based on optical substrates because they are renewable, low cost, and can be ultrathin (< 30 nm). However, forming large diameter films that are sufficiently flat for use in a laser system is a challenge. Here we report the first 24 mm diameter films suitable for multi-PW operation and a new study of the use of LC crystal mixtures optimized for film flatness, allowing improved control and superior films.