Ultrathin glass as a continuously replaceable debris shield for laser systems

High-repetition-rate laser systems require continuous protection of optical components from debris generated during laser-matter interactions. Conventional debris shields offer high optical quality at the cost of inflexible replacement mechanisms or allow easy roll-based replacement but suffer from degraded wavefront performance. In this study, we evaluated the feasibility of ultrathin glass, originally designed for flexible electronic applications, as a continuously replaceable debris shield combining excellent optical and mechanical properties. The optical transmission, wavefront error, and polarization behavior of 50-μm-thick ultrathin glass were characterized and benchmarked against fused silica and nitrocellulose film shields. The ultrathin glass showed high UV-NIR transmittance, minimal wavefront distortion (λ/5 PV, λ/20 RMS), and no observable birefringence. A compact roll-to-roll transport system was developed to support continuous shield renewal in vacuum. Optical stability was tested under active motion using a Ti:sapphire laser delivering 1-J and 40-fs pulses at 10 Hz. The beam pointing deviation remained below 40 µrad during shield translation. Furthermore, high-intensity ion acceleration experiments verified that the shield maintained stable focusing and target interaction over 4000 shots. Degradation was limited to the transmittance loss from debris accumulation with no laser-induced damage. The proposed shield system supports over 300 000 shots with a 20-m-long roll, which can be scaled to hundreds of meters for extended operation. These results demonstrate the viability of ultrathin glass as a practical and scalable debris protection solution for future laser facilities.