Ultrafast pump-probe ellipsometry setup for the measurement of transient optical properties during laser ablation.
Ultrafast pump-probe ellipsometry setup for the measurement of transient optical properties during laser ablation.
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DOI：
10.1364/oe.24.017572
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发表时间：
2016-08
期刊：
影响因子：
3.8
通讯作者：
S. Rapp;Michael Kaiser;Michael Schmidt;H. Huber
中科院分区：
文献类型：
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作者：
S. Rapp;Michael Kaiser;Michael Schmidt;H. Huber
超短脉冲激光在精确和高效的材料加工中提供了很大的潜力，对激光-材料相互作用的基本方面的深入理解非常重要。瞬态脉冲反射率与瞬态吸收一起决定性地影响激光-材料相互作用。直接测量的吸收特性的超快时间分辨椭圆偏振仪失踪的日期。在这项工作中，一个独特的泵探测椭偏显微镜，允许确定的瞬态复折射率与亚ps的时间分辨率。对钼的测量表明，在激光脉冲冲击后的前10 ps内，超快光学穿透深度的变化已经达到-6%至77%。这表明在该时间尺度上照射样品的泵浦脉冲或后续脉冲的显著吸收变化，并且为更好地理解脉冲持续时间依赖的激光烧蚀效率、双或突发模式激光烧蚀和激光脉冲冲击后的第一ps中的晶格修改铺平了道路。
Ultrashort pulsed lasers offer a high potential in precise and efficient material processing and deep understanding of the fundamental laser-material interaction aspects is of great importance. The transient pulse reflectivity in conjunction with the transient absorption influences decisively the laser-material interaction. Direct measurements of the absorption properties by ultrafast time-resolved ellipsometry are missing to date. In this work, a unique pump-probe ellipsometry microscope is presented allowing the determination of the transient complex refractive index with a sub-ps temporal resolution. Measurements on molybdenum show ultrafast optical penetration depth changes of -6% to + 77% already within the first 10 ps after the laser pulse impact. This indicates a significant absorption variation of the pump pulse or subsequent pulses irradiating the sample on this timescale and paves the road towards a better understanding of pulse duration dependent laser ablation efficiency, double or burst mode laser ablation and lattice modifications in the first ps after the laser pulse impact.