Single-shot laser-induced damage threshold (LIDT) measurements of multi-type free-standing ultrathin foils were performed in a vacuum environment for 800 nm laser pulses with durations τ ranging from 50 fs to 200 ps. The results show that the laser damage threshold fluences (DTFs) of the ultrathin foils are significantly lower than those of corresponding bulk materials. Wide band gap dielectric targets such as SiN and formvar have larger DTFs than semiconductive and conductive targets by 1–3 orders of magnitude depending on the pulse duration. The damage mechanisms for different types of targets are studied. Based on the measurement, the constrain of the LIDTs on the laser contrast is discussed.

中文翻译：

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超薄靶材的激光损伤阈值及其对激光驱动离子加速实验中激光对比度的约束

在真空环境中对持续时间 τ 为 50 fs 至 200 ps 的 800 nm 激光脉冲进行了多类型独立式超薄箔的单次激光诱导损伤阈值 (LIDT) 测量。结果表明，超薄箔的激光损伤阈值能量（DTFs）明显低于相应的块状材料。宽带隙介电靶材，例如 SiN 和 formvar，其 DTF 比半导体和导电靶材大 1-3 个数量级，具体取决于脉冲持续时间。研究了不同类型目标的损伤机制。在测量的基础上，讨论了LIDTs对激光对比度的约束。