Ultrafast coherent control of molecular dynamics with shaped laser pulses

利用整形激光脉冲对分子动力学进行超快相干控制

• 批准号: RGPGP-2014-00085
• 负责人: Milner, Valery
• 金额: $ 5.51万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Group
• 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=633146
• 关键词: Ultrafast; coherent; control; molecular; dynamics

Our research is focused on controlling molecular dynamics with high-power ultra-short laser pulses. Specifically, we develop new methods of exciting extreme rotational states – the so called “molecular super rotors”, and investigate the effects of ultra-fast rotation on chemical and physical properties of isolated molecules, molecular clusters and dense molecular gases.Control of molecular rotation has been long recognized and successfully used as a powerful tool for steering chemical reactions, imaging individual molecular orbitals, generating attosecond laser pulses and separating molecular isotopes. Recent theoretical studies have indicated enormous potential in extending the reach of rotational control to ultra-high rotational states. Ultrafast molecular spinning has been predicted to change the character of molecular collisions with solid surfaces and alter molecular trajectories in external fields. New ways of molecular cooling and selective chemical bond breaking by inducing super rotation have been suggested. Yet, owing to multiple technological challenges, no research on molecular super rotors is currently pursued in Canada.In a series of recent works, our research team has successfully demonstrated new approaches to controlling molecular rotation. We have built an “optical centrifuge” and succeeded in producing, observing and controlling molecular super rotors. We also develop a method of exciting extreme rotational states with high-power ultra-short pulse trains. The two methods are complementary and offer different schemes of rotational control.We intend to explore the following unique aspects of molecular science at the limit of extreme rotational speed. (1) Effects of centrifugal distortion and the possibility of selective chemical bond breaking by means of controlled ultrafast molecular spinning; (2) Rotation-induced magnetic properties of diamagnetic and paramagnetic super rotors, including the behaviour of centrifuged molecules in external magnetic field; (3) Rotation-induced electrical properties of polar super rotors, including the possibility for new sources of THz radiation; (4) Dependence of molecule-surface scattering on the orientation and magnitude of the molecular angular momentum; (5) Effects of molecular rotation on superfluidity of helium nanodroplets; (6) Control of quantum molecular rotation in the regime of classically chaotic dynamics; (7) Collisional properties of molecular super rotors and the aspects of rotational energy transfer from isolated molecular rotation to collective gas vortices; (8) Prospects of controlling chemical reactions by tuning molecular rotation in the extreme range of angular frequencies.Similarly to other exotic states of matter, such as ultra-cold atoms or anti-matter, super rotors will provide new insights into the fundamental laws of nature beyond currently established boundaries. We plan to investigate super rotation of hydrogen, nitrogen, oxygen and carbon dioxide - some of the nature’s most fundamental building blocks. The uniqueness of super rotors suggests an immediate impact on general science, and far-reaching effects on modern technology. From a chemistry viewpoint, the effect of ultrafast molecular rotation on chemical reactions begs detailed investigation. From the perspective of physics, we anticipate to find out new electrical, magnetic and optical properties of super rotors. For astronomy, the analysis of extremely hot gases around stars may benefit from the spectroscopy of ultrafast rotating molecules accessible in table-top laboratory experiments. In nano-science, the effects of super rotation on nano-deposition and molecule-surface scattering are of practical interest.

我们的研究重点是用高功率超短激光脉冲控制分子动力学。具体来说，我们开发了激发极端转动态的新方法--所谓的“分子超转子”，并研究了超快转动对孤立分子、分子团簇和致密分子气体的化学和物理性质的影响。分子转动的控制长期以来一直被公认并成功地用作操纵化学反应、成像单个分子轨道、产生阿秒激光脉冲并分离分子同位素。最近的理论研究表明，将转动控制的范围扩展到超高转动态具有巨大的潜力。超快分子自旋可以改变分子与固体表面碰撞的性质，改变分子在外场中的运动轨迹。提出了通过诱导超旋转实现分子冷却和选择性化学键断裂的新途径。然而，由于多重技术挑战，目前加拿大还没有进行分子超级转子的研究。在最近的一系列工作中，我们的研究团队成功地展示了控制分子旋转的新方法。我们建造了一台“光学离心机”，并成功地制造、观测和控制了分子超级转子。我们还发展了一种用高功率超短脉冲序列激发极端转动态的方法。这两种方法是互补的，并提供了不同的方案旋转控制。我们打算探索以下独特的方面的分子科学在极限转速。(1)离心畸变的影响和通过受控超快分子自旋进行选择性化学键断裂的可能性;（2）反磁性和顺磁性超级转子的旋转诱导磁特性，包括离心分子在外部磁场中的行为;（3）极性超级转子的旋转诱导电特性，包括新的太赫兹辐射源的可能性;（4）分子-表面散射与分子角动量的方向和大小的关系，（5）分子旋转对氦纳米液滴超流性的影响，（6）经典混沌动力学区域中量子分子旋转的控制，（7）氦纳米液滴超流性与量子分子旋转的关系，（8）氦纳米液滴超流性与量子分子旋转的关系，（9）氦纳米液滴超流性与量子分子旋转的关系，（10）氦纳米液滴超流性与量子分子旋转的关系，（11）氦纳米液滴超流性与量子分子旋转的关系，（12）氦纳米液滴超流性与量子分子旋转的关系，（13）氦纳米液滴超流性与量子分子旋转的关系。（7）分子超转子的碰撞性质和从孤立分子转动到集体气体涡旋的转动能量传递问题;（8）通过在极端角频率范围内调节分子旋转来控制化学反应的前景与其他奇异的物质状态（如超冷原子或反物质）类似，超级转子将为超越目前既定界限的基本自然规律提供新的见解。我们计划研究氢、氮、氧和二氧化碳的超旋转--这些是自然界最基本的组成部分。超级转子的独特性表明它对普通科学的直接影响，以及对现代技术的深远影响。从化学的观点来看，超快分子旋转对化学反应的影响有待于深入研究。从物理学的角度出发，我们期待着发现新的电、磁、光特性。对于天文学来说，对恒星周围极热气体的分析可能会受益于桌面实验室实验中超快旋转分子的光谱学。在纳米科学中，超旋转对纳米沉积和分子表面散射的影响具有实际意义。