Femtosecond laser machining of biomimetic micro/nanostructures with high aspect ratio (larger than 10) on ultrahard materials, such as sapphire, is a challenging task, because the uncontrollable surface damage usually results in poor surface structures, especially for deep scribing. Here, we report an inside-out femtosecond laser deep scribing technology in combination with etching process for fabricating bio-inspired micro/nanostructures with high-aspect-ratio on sapphire. To effectively avoid the uncontrollable damage at the solid/air interface, a sacrificial layer of silicon oxide was employed for surface protection. High-quality microstructures with an aspect ratio as high as 80:1 have been fabricated on sapphire surface. As a proof-of-concept application, we produced a moth-eye inspired antireflective window with sub-wavelength pyramid arrays on sapphire surface, by which broadband (3–5 μm) and high transmittance (98% at 4 μm, the best results reported so far) have been achieved. The sacrificial layer assisted inside-out femtosecond laser deep scribing technology is effective and universal, holding great promise for producing micro/nanostructured optical devices.

With high hardness, high thermal and chemical stability and excellent optical performance, hard materials exhibit great potential applications in various fields, especially in harsh conditions. Femtosecond laser ablation has the capability to fabricate three-dimensional micro/nanostructures in hard materials. However, the low efficiency, low precision and high surface roughness are the main stumbling blocks for femtosecond laser processing of hard materials. So far, etching-assisted femtosecond laser modification has demonstrated to be the efficient strategy to solve the above problems when processing hard materials, including wet etching and dry etching. In this review, femtosecond laser modification that would influence the etching selectivity is introduced. The fundamental and recent applications of the two kinds of etching assisted femtosecond laser modification technologies are summarized. In addition, the challenges and application prospects of these technologies are discussed.

本文利用共轭聚合物(MEH-PPV)覆盖TiO2纳米粒子薄膜制作随机激光器。随机TiO2纳米粒子薄膜的激光辐射阈值比平面MEH-PPV薄膜的放大自发辐射阈值缩小了9倍。这是由于TiO2纳米粒子诱导的多重散射造成的。进一步的飞秒荧光上转换实验表明，随机激光器中，光在增益介质里的停留时间有所增加，这直接证实了光在随机激光器结构中的多重散射引起光的传播路径增加。因此，这会促进更多的光发生辐射，从而降低随机激光器的阈值。

为了制备具有可控复杂形状和特定化学性质的聚合物微结构，提出了一种飞秒激光直写生物凝胶模板原位合成纳米粒子的方法。首先，采用飞秒激光直写技术加工带有COOH基团的复杂三维结构的生物凝胶模板，用氢氧化钠处理使COOH基团离子化为COO-基团; 然后，用金属盐溶液处理，使金属离子与COO-基团螯合，形成纳米粒子结晶核。通过多次循环盐溶液处理步骤，控制模板中纳米粒子的粒径与含量。实验结果表明: 所制备的生物凝胶模板具有亚100 nm分辨率和10 μm量级尺寸，纳米粒子含量高达9%。该法简单高效，具有很好的应用前景。

超快光谱技术是研究物质激发态过程的重要手段，本文对飞秒时间分辨荧光技术和飞秒泵浦探测技术这两个重要的超快光谱技术进行了详细介绍，阐述了系统的原理、光路及数据处理方法，给出了不同的实现方法并比较了其优缺点。最后通过一个实例说明这两个技术的互补性，通过结合使用两个系统，能够对科学问题进行更全面可靠的研究。