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.