Two-stage compression of laser pulses with a power of 250 TW is experimentally realised by broadening their spectrum during self-phase modulation in fused silica and subsequent dispersion compensation upon reflection from chirping mirrors. A fivefold decrease in the duration is demonstrated, from 75 to 15 fs, with a B-integral value of about 5 at each stage. It is possible to avoid small-scale self-focusing due to self-filtering of the laser beam during free propagation in vacuum. With optimal parameters of the dispersive mirror, the pulse can be compressed to a duration of less than 5 fs.

中文翻译：

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高功率飞秒激光脉冲的两级非线性压缩

功率为 250 TW 的激光脉冲的两级压缩是通过在熔融石英中的自相位调制期间加宽其光谱以及随后在啁啾镜反射时进行色散补偿来实现的。持续时间减少了五倍，从 75 到 15 fs，每个阶段的 B 积分值约为 5。由于激光束在真空中自由传播期间的自过滤，可以避免小规模自聚焦。通过色散镜的最佳参数，脉冲可以被压缩到小于 5 fs 的持续时间。