Ultrafast Laser Matter Interactions

超快激光物质相互作用

• 批准号: RGPIN-2014-03706
• 负责人: Tsui, Ying
• 金额: $ 3.06万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=633182
• 关键词: Ultrafast; Laser; Matter; Interactions

In the proposed research program, basic science and applications oriented research in ultrafast laser matter interactions will be carried out. In the basic science research, we will focus on the quantitative understating of the first several picoseconds of ultrafast laser heating of solids. At this early time a solid can be heated to several electron Volts (eV) but remain at solid density. A heated solid with high energy density is called Warm Dense Matter (WDM) which is currently a forefront area of study in material science. The study of materials under extreme conditions has generated enormous scientific interest and was identified by the National Academy of Sciences and the National Science and Technology Council in USA as a priority research area for this century. The understanding of WDM is important for laser material processing, which has many scientific and industrial applications, as well as Inertial Fusion Energy, which is a safe energy source that has no carbon emission and almost unlimited fuel supply.Our experimental platform is based on probing the properties of a free standing ultrathin target foil heated by an ultrafast laser pulse. The experimental platform is designed to generate single state WDM with no temperature and density gradients providing simplification in the comparison of results from experiments and theories. For example, for a gold nanofoil target of thickness of 30 nanometers, the uniform heating throughout the entire nanofilm thickness is made possible by ballistic electron transport because the ballistic electrons have a range of ~100 nm. Single state warm dense gold with a solid density, a low ion temperature and a high electron temperature of several eV is created in the first few hundred femtoseconds. The solid density lasts for several picoseconds before it dissembles into an expanding plasma. Since the non-equilibrium WDM lasts for several picosecond, its properties can be studied in detail experimentally by probing it with ultrafast probes. We plan to study the WDM using ultrafast THz, optical, X-ray and electron probes by developing state-of-art diagnostic techniques making use of the capabilities in U of Alberta and other world-class facilities including 100 TW class laser systems at the Advanced Laser Light Source (ALLS) in Quebec as well as at the SLAC National Accelerator Laboratory in California, and the unique high brightness X-ray Free Electron Laser (XFEL) system at SLAC. The theory of WDM presents a great challenge for theorists because WDM is too hot for condensed matter theories and too dense for traditional plasma theories. We will work together with a team of theorists to tackle this challenge.Several laser applications are of interest to us and we will continue to carry out studies in these areas. We have carried out studies on laser induced forward transfer (LIFT), a laser printing technique, in particular studying the potential of LIFT for nanofabrication. We have demonstrated LIFT with transferred features with sizes below 70 nm. We have carried out studies to investigate the feasibility of using femtosecond laser pulses to tune the resonant frequency of silicon ring resonators permanently. We have demonstrated bi-directional frequency tuning of silicon ring resonators by making use of the ultrafast laser induced amphorization and ablation processes. We have also successfully demonstrated Schottky barrier field effect ZnO transistors with high mobility. The ZnO thin films are produced using laser ablation at a relatively low substrate heating temperature of 250 degree C which is compatible with substrates for flexible electronics applications. We will continue to optimize these techniques through better understanding of the basic physical processes.

在拟议的研究计划中，将进行以超快激光物质相互作用的基础科学和应用为导向的研究。在基础科学研究中，我们将重点介绍对固体的超快激光加热前几个皮秒的定量低估。在此早期，可以将固体加热到几个电子伏特（EV），但保持固体密度。具有高能量密度的加热固体称为温暖密集物质（WDM），目前是材料科学研究的最前沿领域。对极端条件下的材料的研究引起了巨大的科学兴趣，并被美国国家科学院和美国国家科学技术委员会确定为本世纪的优先研究领域。对WDM的理解对于激光材料加工很重要，它具有许多科学和工业应用，以及惯性融合能，这是一个没有碳排放且几乎无限燃料供应的安全能源。我们的实验平台基于探测自由站立的超级超平整材料的特性，该属性由超级抗激光脉冲的自由静电材料加热。实验平台旨在生成单个状态WDM，没有温度和密度梯度，可简化实验和理论的结果。例如，对于30纳米厚度的金纳米为目标，弹道电子传输使整个纳米厚度的均匀加热成为可能，因为弹道电子的范围约为100 nm。在前几百个飞秒中，产生了具有固体密度，低离子温度和高电子温度的单态温暖的黄金，低离子温度和高电子温度。固体密度持续几个皮秒，然后将其分解成扩展的等离子体。由于非平衡WDM持续了几个picsecond，因此可以通过用超快探针探测其特性。 We plan to study the WDM using ultrafast THz, optical, X-ray and electron probes by developing state-of-art diagnostic techniques making use of the capabilities in U of Alberta and other world-class facilities including 100 TW class laser systems at the Advanced Laser Light Source (ALLS) in Quebec as well as at the SLAC National Accelerator Laboratory in California, and the unique high brightness X-ray Free Electron Laser （XFEL）SLAC的系统。 WDM理论对理论家提出了巨大的挑战，因为WDM对于凝结的物质理论太热，对于传统的等离子体理论来说太密集了。我们将与一个理论家团队一起应对这一挑战。我们感兴趣的几个激光应用程序，我们将继续在这些领域进行研究。我们已经对激光诱导的正向转移（LIFT）进行了研究，这是一种激光打印技术，尤其是研究了纳米制作的升力潜力。我们已经证明了升力，其尺寸低于70 nm。我们已经进行了研究，以研究使用飞秒激光脉冲永久调整硅环谐振器的谐振频率的可行性。我们已经通过使用超快激光诱导的两种化工和消融过程来证明硅环谐振器的双向频率调整。我们还成功地证明了具有较高迁移率的Schottky屏障场效应ZnO晶体管。 ZnO薄膜是使用激光消融在相对较低的250度C的底物加热温度下生产的，该温度与柔性电子应用的底物兼容。我们将通过更好地理解基本物理过程来继续优化这些技术。