Irradiation of solids with ultrashort pulses and laser processing in the mid-Infrared (mid-IR) spectral region is a yet predominantly unexplored field with a large potential for a wide range of applications. In this work, laser driven physical phenomena associated with processes following irradiation of fused silica (SiO₂) with ultrashort laser pulses in the mid-IR region are investigated in detail. A multiscale modelling approach is performed that correlates conditions for formation of perpendicular or parallel to the laser polarisation low spatial frequency periodic surface structures for low and high intensity mid-IR pulses (not previously explored in dielectrics at those wavelengths), respectively. Results demonstrate a remarkable domination of tunneling effects in the photoionisation rate and a strong influence of impact ionisation for long laser wavelengths. The methodology presented in this work is aimed to shed light on the fundamental mechanisms in a previously unexplored spectral area and allow a systematic novel surface engineering with strong mid-IR fields for advanced industrial laser applications.

在中红外（mid-IR）光谱区域中以超短脉冲辐照固体和进行激光处理是一个尚未开发的主要领域，具有广阔的应用前景。在这项工作中，激光驱动的物理现象与熔融石英（SiO ₂）中红外区域的超短激光脉冲进行了详细研究。进行了多尺度建模方法，该方法分别针对低强度和高强度中红外脉冲（以前从未在那些波长的电介质中探索过），使形成垂直或平行于激光偏振低空间频率周期性表面结构的条件相互关联。结果表明，在长距离激光波长中，隧穿效应在光电离速率中具有显着优势，而碰撞电离则具有强大的影响力。这项工作中提出的方法旨在阐明以前未曾探索过的光谱区域中的基本机理，并为先进的工业激光应用提供具有强大的中红外场的系统性新颖表面工程。