Tomography of femtosecond laser structured objects inscribed in glass

玻璃的激光加工是一个年轻的研究领域，但发展迅速。特别是内部玻璃改性和加工可以导致各种新的应用，这些应用利用激光改性的性质，例如折射率、体积、双折射、玻璃网络连接性或热力学相态。未来可能的技术包括减材和增材玻璃加工制造的组合，以及光机电组件、纳米流体、波导或光学元件的小型化。这些具有新特性的新器件可能会对未来的生物医学、光机电应用产生重大影响。 尽管在文献中已经报道了关于这一主题的大量工作，但激光诱导转变的性质仍然几乎不被理解。本建议的主要目的是获得一个基本的理解超短脉冲激光玻璃相互作用的短和较长的脉冲持续时间以及单脉冲和多脉冲照射，因为它是已知的文献和初步结果，玻璃激光相互作用是强烈依赖于玻璃类型和激光参数。虽然对某些类型的观察到的相互作用的局部解释确实存在，但它们缺乏必要的范围来预测不同玻璃组合物或辐照参数的玻璃行为。因此，在本发明中，本项目的目标是通过将激光玻璃相互作用的空间和时间分辨观测与拉曼和布里渊光谱学以及透射电子显微镜（TEM）和飞行时间二次质谱学相结合，获得足够的信息，以制定激光玻璃相互作用的适当模型（TOF-SIMS）来检测结构和化学改性，由此可以恢复玻璃与激光脉冲的相互作用历史。这使得玻璃-激光相互作用的详细建模成为可能。实验和模型将在纳米到毫米的范围内为从皮秒到无穷大的时间尺度提供对潜在过程的连续观察。新的基于实验室的纳米X射线显微镜（CZ Xradia 810 Ultra即将在Halle上市）可以填补1 µm和50 nm之间的观测空白。特别强调的是激光物质相互作用的化学方法。为此，将合成大量的玻璃，化学敏感技术，如时间分辨发射光谱，TOF-SIMS和XRM将有助于在所有基础过程中具体跟踪每种化学元素。

Laser processing of glass is a young research field, yet under immense and steadily-increasing development. Especially internal glass modifications and processing could lead to various new applications that make use of laser modified properties such as refractive index, volume, birefringence, glass network connectivity or thermodynamic phase states. Possible future technologies encompass a combination of subtractive and additive glass processing fabrication and miniaturization of optomechatronic components, nanofluidics, waveguides, or optical elements. These new devices with novel properties could have a strong impact on future biomedical, optomechatronic applications. Even though a considerable amount of work on this topic has been reported in literature, the nature of laser-induced transformations is still barely understood. The main objective of this proposal is to obtain a fundamental understanding of the ultra-short pulsed laser-glass interaction for short and longer pulse durations as well as for single pulse and multi pulse irradiation since it is known from literature and preliminary results that the glass-laser- interaction is strongly dependent on the glass type and laser parameters. While localized explanations for certain types of observed interactions do exist, they lack the necessary scope to predict the glass behavior for a different glass composition or irradiation parameters. Thus, the aim of this project is to gain sufficient information to formulate an adequate model of the laser glass interaction by connecting the spatially and time resolved observation of the laser glass interaction with Raman and Brillouin spectroscopy as well as transmission electron microscopy (TEM) and time-of-flight secondary mass spectrometry (TOF-SIMS) to detect structural and chemical modifications by which the interaction history of the glass with the laser pulse can be recovered. This makes detailed modelling of the glass-laser-interaction possible. The experiments and the model will give a continuous vision on the underlying processes in a range of nanometer to millimeter for time scales from pikosecond up to infinity. The new laboratory-based, nanometric x-ray microscopy (with the CZ Xradia 810 Ultra soon becoming available in Halle) can fill the missing observation gap between 1 µm and 50 nm. A special emphasis will be given to a chemical approach of the laser matter interaction. For that a large set of glasses will be synthesized and chemically sensitive techniques such as time resolved emission spectroscopy, TOF-SIMS and XRM will help to follow specifically each chemical element through all the underlying processes.