Strong-Field Molecular Processes: From Novel Spectroscopies to Lasing in Air

强场分子过程：从新颖的光谱学到空气中的激光

• 批准号: RGPIN-2017-06811
• 负责人: Spanner, Michael
• 金额: $ 2.19万
• 依托单位: University of Ottawa
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=712461
• 关键词: Strong; Field; Molecular; Processes; Novel

My research focuses on the quantum description of laser-matter interactions. When strong laser fields interact with molecules, a number of interesting opportunities arise. First, it is possible to use the lasers to control molecular motions. In particular, my research has highlighted methods to control molecular alignment and orientation in space, where laser-based techniques can force all the molecules in a gas to be aligned or point along a single direction. I am also interested in methods to use strong laser fields to probe and investigate the details of molecular motion, both how the nuclei vibrate and rotated, and how the electrons move within the molecules. To this end, my research also involves methods to probe molecular motion where we use the molecules' own electrons to investigate the molecular motions occurring within the molecules. We first use the laser fields to quickly remove one of the molecule's electrons, accelerate this electron to high velocities, and then throw the electron back at the parent molecule. By measuring what happens when this electron recollides with the parent molecule, we can gain valuable information about the particular dynamics occurring in the molecule. This method of probing the molecular dynamics can be compared to using a very fast camera flash, where the light of the flash reflects off of the object of interest, and the camera records how the light scatters from the object. In the molecular case, the electron that was removed from the molecular acts as a `flash' that illuminates the molecule. Measuring the scattered electron is analogous to measuring the scattered flash with the camera. These methods offer unprecedented temporal resolution that will help us understand electronic motions with molecules. In addition to controlling and probing molecules with strong laser fields, I am interested in understanding a relatively new process that occurs when strong laser fields propagate through air. Research groups around the world have discovered that, when focusing high intensity lasers into air, the nitrogen molecules can sometimes act as a new lasing medium for a second delay weak light pulse. Effectively, energy from the first laser pulse is deposited in the nitrogen molecules, and this deposited energy can be used to amplify a weaker second light pulse. The details of exactly how the energy from the first laser pulse is deposited into the nitrogen molecules is not currently well understood, and my research aims to uncover the underlying mechanism. Understanding the underlying mechanism could lead to opportunities to optimize this process for remote sensing and standoff detection applications.

我的研究重点是激光与物质相互作用的量子描述。当强激光场与分子相互作用时，出现了许多有趣的机会。 首先，可以用激光控制分子运动。特别是，我的研究强调了控制分子在空间中排列和取向的方法，其中基于激光的技术可以迫使气体中的所有分子排列或沿沿着一个方向指向。我还对使用强激光场来探测和研究分子运动的细节的方法感兴趣，包括原子核如何振动和旋转，以及电子如何在分子内移动。为此，我的研究还涉及探测分子运动的方法，我们使用分子自身的电子来研究分子内发生的分子运动。我们首先使用激光场快速去除分子中的一个电子，将该电子加速到高速，然后将电子抛回母体分子。通过测量这个电子与母体分子碰撞时发生的情况，我们可以获得有关分子中发生的特定动力学的有价值的信息。这种探测分子动力学的方法可以与使用非常快的相机闪光灯进行比较，其中闪光灯的光从感兴趣的对象反射，并且相机记录光如何从对象散射。在分子的情况下，从分子中移除的电子充当照亮分子的“闪光”。测量散射电子类似于用相机测量散射闪光。这些方法提供了前所未有的时间分辨率，将帮助我们理解分子的电子运动。除了用强激光场控制和探测分子外，我还对理解强激光场在空气中传播时发生的相对较新的过程感兴趣。世界各地的研究小组发现，当将高强度激光聚焦到空气中时，氮分子有时可以作为一种新的激光介质，产生第二延迟的弱光脉冲。有效地，来自第一激光脉冲的能量沉积在氮分子中，并且该沉积的能量可以用于放大较弱的第二光脉冲。关于第一个激光脉冲的能量是如何沉积到氮分子中的细节目前还没有很好的了解，我的研究旨在揭示潜在的机制。 了解潜在的机制可能会导致机会，以优化这一过程的遥感和对峙探测应用。