Printed optics by ultrafast laser nanostructuring of glass

超短光脉冲与透明材料的相互作用是一种极其复杂的现象，涉及巨大的压力（100万个大气压）和极端的温度（>3000 K）-在这些条件下材料被改性的过程仍然不清楚。通过理解和控制这种相互作用，我们可以利用超短光脉冲，为先进的光子制造行业提供纳米级材料加工。在这个项目中，我们的目标是开发光学元件到玻璃的印刷技术，使用超快激光纳米结构，利用激光脉冲强度，相位和偏振在空间和时间域的定制。该印刷技术是基于飞秒激光诱导的自组织亚波长周期性结构，称为纳米光栅，其特征小至20 nm。我们的最终目标是生产一种可印刷的各向异性无机材料，它结合了无机晶体（如石英）的耐用性和光学质量以及液晶的可制造性。为实现这一宏伟目标，我们将致力于以下几个方面的工作：（1）建立一个描述超快激光脉冲与透明材料相互作用的理论框架，包括时空效应和光与电子等离子体波之间的相干相互作用;（2）控制超快激光束的时空特性，以便在石英玻璃上压印高度有序的纳米结构;（iii）利用超快激光压印纳米-用于制造具有前所未有的质量和可制造性的先进光子器件的结构。实验工作将涵盖超短脉冲的几个方面。激光玻璃纳米结构化工艺。激光-物质相互作用的原位监测将被用作优化超快激光纳米结构化过程的反馈，并将导致超快激光脉冲在真实的时间内的时空剪裁方法的发展。实验和理论框架将使我们能够理解在发挥作用的基本机制，包括激光束传播的动力学，光的吸收和自由电子等离子体的激发。超快激光打印技术的优势将被利用来展示用于高分辨率光学显微镜、偏振敏感成像和高功率激光材料加工的新型光子器件。随着超快激光器在不久的将来趋于工业化，这项研究除了具有根本的重要性外，还将通过提供对数据存储，集成和衍射光学和成像技术产生影响的物质的可控改性，极大地推进3D激光直写领域。

The interaction of an ultrashort light pulse with transparent material is an extremely complex phenomenon involving enormous pressures (1 million atmospheres), and extreme temperatures (>3000 K) - the process by which materials are modified under these conditions is still not clear. By understanding and controlling this interaction we can harness ultrashort light pulses enabling nanoscale processing of materials for advanced photonics manufacturing sectors.In this project we will aim to develop printing technology of optical elements into glass, using ultrafast laser nano-structuring, exploiting tailoring of laser pulse intensity, phase and polarization in space and time domain. The printing technology is based on femtosecond laser induced self-organized sub-wavelength periodic structures referred as nanogratings with features as small as 20 nm. Such a periodic assembly behaves as quartz exhibiting strong birefringence.Our ultimate goal is to produce a printable anisotropic inorganic material, which combines the benefits of durability and optical quality of inorganic crystals (e.g. quartz) with the manufacturability of liquid crystals. The reach this ambitious goal the following objectives will be pursued:(i) to create a theoretical framework describing the interaction of ultrafast laser pulses with transparent materials, which includes spatio-temporal effects and coherent interaction between light and electron plasma waves; (ii) to control spatio-temporal properties of ultrafast laser beam for imprinting highly ordered nano-structures in quartz glass; (iii) to utilize ultrafast laser imprinted nano-structures for fabrication of advanced photonic devices with unprecedented quality and manufacturability.Experimental work will cover several aspects of ultrashort lasers glass nano-structuring process. In-situ monitoring of laser-matter interaction will be used as feedback for optimisation ultrafast laser nano-structuring process and will lead to the development of method for spatio-temporal tailoring of ultrafast laser pulses in real time. The experimental and theoretical framework will enable us to understand the fundamental mechanisms at play including the dynamics of laser beam propagation, absorption of light and excitation of the free electron plasma. The advantages of ultrafast laser printing technique will be exploited to demonstrate novel photonic devices for high resolution optical microscopy, polarization sensitive imaging and high power laser material processing. As ultrafast lasers tend to become industrially accessible in the nearest future, this research, besides its fundamental importance, will dramatically advance the fields of 3D laser direct writing by providing controllable modification of matter with impact on technologies of data storage, integrated and diffractive optics and imaging.