Theoretical Concepts for Generation and Characterization of Ultraviolet Laser Pulses

紫外区是电磁光谱的重要部分，因为许多原子、分子、纳米颗粒和材料的激发和电离能都在这个光谱区。在紫外波长下工作的光源可用于在超快时间尺度上触发、引导、探测和成像材料中的物理过程、化学反应和转变。除了对基础科学研究的重要性外，紫外激光还可应用于纳米技术、微光刻和微机械加工、医学和其他领域。然而，科学结果的应用和解释仍然受到限制，这是由于缺乏在紫外波长处产生良好表征的短脉冲的明亮的可调谐光源。该项目的研究将通过开发和应用新的理论方法来理解短脉冲紫外激光产生的各个方面，并在实验中测量产生的超短脉冲，从而促进这一领域的科学进步。研究生将接受理论原子，分子和光学物理学前沿课题的培训。这包括分析实现项目目标的概念，开发软件及其应用，以及以口头和书面形式传播成果。本项目的重点是为短脉冲紫外激光光源的研制提供理论支持。为此，将对气体喷射实验中的宏观高次谐波产生进行数值模拟。特别强调的是，将给出一个短的高斯激光脉冲产生的谐波响应的激光焦点的空间相位依赖性的影响的分析。将确定谐波辐射的良好相干积累的条件，并分析实验限制的影响，如激光强度或气体密度的波动。此外，一个多高斯自动和互相关的方法及其应用到各种脉冲forms.This奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

The ultraviolet region is an important part of the electromagnetic spectrum since excitation and ionization energies of many atoms, molecules, nanoparticles, and materials lie in this spectral regime. Light sources operating at ultraviolet wavelengths can be used to trigger, steer, probe, and image physical processes, chemical reactions and transitions in materials on ultrafast time scales. Beyond their significance for fundamental scientific research, applications of ultraviolet lasers can be found in nanotechnology, microlithography and micromachining, medicine and other areas. Applications and interpretation of scientific results are however still limited due to a lack of bright tunable light sources generating well-characterized short pulses at ultraviolet wavelengths. Research in this project will promote the progress of science in this area by developing and applying new theoretical methods to understand aspects of the generation of short-pulsed ultraviolet laser light and to measure the generated ultrashort pulses in experiments. A graduate student will receive training in a forefront topic in theoretical atomic, molecular, and optical physics. This includes the analysis of concepts towards the project goals, the development of software and its applications, as well as the dissemination of the results in oral and written form. The focus of this project is to provide theoretical support for the development of short-pulsed ultraviolet laser sources. To this end, numerical simulations of the macroscopic high harmonic generation in a gas jet experiment will be performed. Specific emphasis will be given to the analysis of the impact of the spatial phase dependence across the laser focus of a short Gaussian laser pulse generating the harmonic response. Conditions for good coherent build-up of harmonic radiation will be identified and the influence of experimental limitations, such as fluctuations in laser intensity or gas density, will be analyzed. Furthermore, a multi-Gaussian auto- and cross-correlation approach and its application to various pulse forms will be investigated.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.