Theory and Simulation of Laser Dressed Molecules and Materials

罗彻斯特大学的伊格纳西奥·佛朗哥（Ignacio Franco）获得了化学系化学理论、模型和计算方法项目的奖励，他发展了激光驱动或“装扮”时物质涌现特性的理论和模拟。表征和控制被激光驱动远离平衡状态的物质是科学和技术的关键挑战。这是因为当物质被激光提供的强相干光震动时，其行为会非常不同。此外，激光提供了在超快时间尺度（十亿分之一秒的百万分之一）上进行操作的可能性，这是通过施加电压、化学或热力学控制等更传统的手段根本无法实现的。弗朗哥小组将开发物质中电子的激光控制的一般方案，并在此过程中促进一类新型激光修饰动态材料的发展，这些材料具有“按需”有效特性，可在超快时间尺度上进行调节。该小组最近提出的建议包括利用光来驱动超快的电流，将绝缘体变成导体，以及将透明材料变成宽带吸收体。除了能够用激光操纵电子动力学的基本兴趣之外，这种能力也为超快电子，开关，成像，催化，以及事实上，任何基于电子及其控制的科学和技术的发展奠定了基础。该提案的推广活动包括组织年度会议，探索分子科学中的量子前沿，通过开发“量子动力学”研究生课程将研究与教育结合起来，并推进罗切斯特大学增加STEM多样性的举措。具体来说，佛朗哥小组将研究电子量子控制的基本限制，并提高我们使用高强度和中等强度超快激光脉冲来操纵分子、纳米结构和扩展系统中的电子特性和动力学的能力。该小组对由强非共振激光场引起的斯塔克效应引发的效应特别感兴趣。这些场以动态和可逆的方式有效地改变能级，从而产生具有瞬态特性的激光修饰材料，这些材料可能与热力学平衡附近观察到的材料大不相同。总的目标是了解激光修饰物质吸收光、传输电荷以及利用光控制电子动力学的能力。为此，该小组将发展基于floquet的物质光学吸收特性理论，纳米级结中激光驱动电流的理论和模拟，并推进使用基于Stark的策略来控制材料界面的电子动力学。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Ignacio Franco of the University of Rochester is supported by an award from the Chemical Theory, Models and Computational Methods program in the Division of Chemistry to develop the theory and simulation of the emergent properties of matter when driven or “dressed” by lasers. Characterizing and controlling matter driven far from equilibrium by lasers represents a key challenge for science and technology. This is because matter can behave very differently when shaken by the intense coherent light provided by lasers. Further, lasers offer the possibility of manipulation on an ultrafast timescale (on the order of a millionth of one billionth of a second), something that is simply not achievable by more conventional means such as an applied voltage, chemical or thermodynamic control. The Franco group will develop general schemes for the laser control of electrons in matter and, in doing so, catalyze the development of a novel class of laser-dressed dynamical materials with “on-demand" effective properties that are tunable on an ultrafast timescale. Recent proposals by the group include the use of light to drive ultrafast electronic currents, turn insulators into conductors, and optically transparent materials into broadband absorbers. In addition to the fundamental interest in being able to manipulate electron dynamics with lasers, this ability also serves as the basis for the development of ultrafast electronics, switching, imaging, catalysis, and, in fact, any science and technology at large based on electrons and their control. The outreach activities of this proposal include the organization of annual conferences exploring quantum frontiers in molecular science, integrating research with education by developing a graduate course on “Quantum Dynamics”, and advancing initiatives to increase diversity in STEM at the University of Rochester. Specifically, the Franco group will investigate the fundamental limits in the quantum control of electrons and advance our capabilities to use high and intermediate intensity ultrafast laser pulses to manipulate electronic properties and dynamics in molecules, nanostructures and extended systems. The group is particularly interested in effects that are triggered by the Stark effect induced by strong non-resonant laser fields. These fields effectively modify the energy levels in a dynamic and reversible fashion thus creating laser-dressed materials with transient properties that can be very different from those observed near thermodynamic equilibrium. The general objective is to understand the ability of laser-dressed matter to absorb light, transport charge, and the use of light to control electron dynamics. For this, the group will develop Floquet-based theories of the optical absorption properties of matter, the theory and simulation of laser-driven currents in nanoscale junctions, and advance the use of Stark based strategies to control electron dynamics at material interfaces.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.