Ultr-intense and Ultra-fast laser-matter interaction physics

这个以实验为主的研究计划的主要目标是在物质和飞秒脉冲的超短超强光场之间的相互作用中隐含的一组新的物理关系。近期的主要努力将集中在两个领域：1)在超高、相对论相关强度下产生的相当基础的等离子体物理学(&gt；10^{18}W/cm^{-2})：高次谐波产生、阿秒脉冲产生、高场相互作用下德拜屏蔽的变化、激光粒子耦合的相对论变化、高能离子和电子的产生；以及(2)与超快激光材料相关的公平应用的光学和等离子体物理-玻璃和非金属的加工，包括微加工和直接索引写入；此外，我们还在研究与医疗应用相关的生物组织的相关问题。这些领域中的第一个领域可能有助于对相对论激光-等离子体相互作用的基本了解，并可能导致与激光聚变的“快速点火”方案相关的实际应用物理学。我们可以在我的实验室对太瓦CPA激光器进行培训和初步实验，但大多数可发表的工作必须在国际上的大型激光系统之一上进行，例如法国的CEA-Saclay(Salle Chaude)或加拿大的ALLS激光系统。第二个领域与实验有关，因为它涉及超快激光，但强度更适中。它满足了学生在激光与物质相互作用实验中的动手培训需求，并提供了一个更广泛的应用和工业相关的研究组成部分，同时仍然强调科学。这项工作在我自己的实验室中使用了两个系统：一个是133 MHz的脉冲雨爆发激光系统，一个是1 ps脉冲的系统，另一个是以kHz和80 MHz的速率提供100 ps脉冲的系统。这项研究包括内部和与其他地方合作的适度的分析和计算理论部分，包括一维和二维的相对论激光-等离子体相互作用的粒子-单元(PIC)代码模拟，以及固体的分子动力学(MD)模拟。以及等离子体中的光束通道。强激光-等离子体相互作用物理中最棘手的问题一直是观察新的效应，同时人们通过经验确定相互作用的条件--这是一个特别困难和复杂的超强激光产生的等离子体的诊断问题。我的研究风格一直是明确设定定义/诊断的实验问题，适合与理论预测进行比较，而不是立即采取行动，从现象学的角度去追求极端的条件。我们在理论诊断和建模方面积累的专业知识非常适合像我这样大小的一个小组。

The main target of this mostly-experimental research program is the set of new physical relations implicit in  the interplay between matter and ultrashort ultra-intense optical fields of femtosecond pulses.  The principal near-term efforts will be concentrated in two areas:  1) fairly basic plasma physics which arises at ultra-high, relativisitically relevant intensities (> 10^{18} W  cm^{-2}):  high-harmonic generation, attosecond pulse generation, changes in Debye shielding under  high-field interactions, relativistic changes in laser-particle coupling, and generation of energetic ions and  electrons; and  2) fairly applied optical- and plasma-physics relevant to ultrafast-laser materials-processing of glasses and  metals, including micromachining and direct index-writing;  we are also studying related problems with  biotissues, relevant to medical applications.The first of these areas is likely to contribute to basic understanding of relativistic laser-plasma interactions,  and may lead to practical applied physics relevant to the 'fast ignitor' scheme of laser-fusion.  Training and  preliminary experiments can take place on the terawatt CPA laser in my laboratory, but most publishable work  must take place on one of the large international laser systems, e.g., CEA-Saclay ('Salle Chaude') in France, or  the ALLS laser system in Canada.The second area is experimentally related, in that it involves ultrafast lasers but at more moderate intensities.   This meets the needs for hands-on training of students in laser-matter interaction experiments, and provides an  applied and industrially relevant component of research while still emphasizing the science. This work uses  two systems in my own laboratories:  a 133 MHz pulsetrain burst laser system of 1 ps pulses, and a system of  100fs pulses at kHz and 80 MHz rates. The research includes a modest analytical and computational theory component, in-house and in collaboration  elsewhere, including particle-in-cell (PIC) code simulations of relativistic laser-plasma interactions in 1D and  in 2D, and also molecular dynamic (MD) modelling of solids.  Analytically, we conduct effective-dielectric  modelling of nanostructured materials, and of beam-channelling in plasmas.The thorniest problem of intense laser-plasma interaction physics has been to observe new effects while at the  same time one determines the conditions of interaction empirically -- a particularly difficult and complex  diagnostic problem for ultra-intense laser-produced plasmas.  My research style has been to set cleanly  defined/diagnosed experimental problems, suited for comparison to theoretical predictions, rather than  immediately to pursue 'extreme' conditions phenomenologically.  The expertise we have developed in  diagnostics and also in modelling are well-suited to a group the size of mine.