Multiple 11-fs infrared, few-cycle laser pulses were applied to a polycrystal ZnSe surface to study the evolution of surface damage morphologies. The polycrystalline grain boundaries seem to be the initiation site of surface damage and formation of ripples, which evolve as the result of many laser pulses at the same site. Scanning electron microscopy and atomic force microscopy (AFM) were applied to characterize the surface. The crystalline change and material phase transition were examined by confocal Raman spectroscopy. The thermal expansion coefficient increased slightly in the ablated zone compared to the non-ablated zone according to an AFM thermal tip test. The results show the growth and organization of surface ripples and the change of thermal properties as the number of irradiations at each site increases.

中文翻译：

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多脉冲，少周期，激光损伤的ZnSe的表面结构演变和拉曼响应

将多个11 fs红外，几个周期的激光脉冲应用于多晶ZnSe表面，以研究表面损伤形态的演变。多晶晶界似乎是表面损伤和波纹形成的起始点，这是由于同一位置上许多激光脉冲的影响而演变的。扫描电子显微镜和原子力显微镜（AFM）用于表征表面。通过共聚焦拉曼光谱检查晶体的变化和材料的相变。根据AFM热尖端测试，与未烧蚀区相比，烧蚀区的热膨胀系数略有增加。结果表明，随着每个位置照射次数的增加，表面波纹的形成和组织以及热性能的变化。