Waveform Synthesis of Attosecond Optical Pulses: A Common Route to Attosecond Pump-Probe Spectroscopy and Nanoscopy in Aqueous Solution

阿秒光脉冲的波形合成：水溶液中阿秒泵浦探针光谱学和纳米显微镜学的共同途径

• 批准号: RGPIN-2015-06208
• 负责人: BeaudoinBertrand, Julien
• 金额: $ 2.4万
• 依托单位: Université Laval
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=644886
• 关键词: Waveform; Synthesis; Attosecond; Optical; Pulses

When a molecule absorbs light, its electronic cloud reacts almost instantaneously followed by rovibrational nuclear dynamics on the femtosecond (fs=10-15s.) to picosecond (ps=10-12s.) timescale. In photosynthesis, for example, the absorption of ultraviolet light by chlorophyll molecules induces an electronic dipole oscillation, which has a period in the range of 1 fs, followed by its slower decay and energy redistribution to the nuclear degrees of freedom. Over the last decades, time-resolved spectroscopy showed how few-cycle femtosecond laser pulses can be used to steer nuclear wave packets and control the outcome of elementary reactions. The lack of shorter pulses, however, has left control of the electron wave packets on the sub-oscillation period timescale unexplored. Would it be possible to follow and, ultimately, more efficiently control reaction dynamics right from the earliest moments when electron dipole forces initiate nuclear motion?****The emerging field of Attosecond Physics offers a new take on these questions. In fact, both isolated extreme ultraviolet (XUV, 10-100 eV) and broadband optical attosecond (as=10-18 s.) pulses can be simultaneously produced and synchronized with common tabletop femtosecond optical technology. Recent laser developments even extend the attosecond emission from the XUV to "water window" soft X-rays (280-500eV) and beyond. This feat radically departs from the shortest picosecond pulses so far only available from large scale (0.1-10 km) accelerator facilities. The water window designates the spectral range where water is essentially transparent to the radiation while carbon and nitrogen atoms are highly absorptive; enabling novel high-contrast, element-specific, time-resolved spectroscopy and nanoscopy in water. Combining my experience in time-resolved molecular spectroscopy (Ph.D, University of Ottawa, director: Paul Corkum) with a unique -in Canada- expertise in attosecond technology and optical waveform synthesis (Banting postdoctoral fellowship at the Max-Planck-Institut for Quantum Optics in Munich, 2013-2014, director: Ferenc Krausz), my research group has the long term vision:***To make possible the spectroscopy of biomolecules in aqueous solution with unexplored time and spatial resolutions through the implementation of optical waveform synthesis providing both optical and water window soft X-ray attosecond pulses.***By the end of year 5, we will have:***1) Demonstrated optical waveform synthesis to generate coherent soft X-ray water window radiation. ***2) Used this radiation for the spectroscopy of molecules in aqueous phase in unexplored attosecond regime.***3) Used the ultrashort wavelength of coherent soft X-rays (2-10 nm) to spatially resolve nanometric structures.***This interdisciplinary research will train highly qualified personnel and open avenues for new technological applications in health sciences.*** *** *** **

当一个分子吸收光时，其电子云几乎立即反应，然后在飞秒上（FS = 10-15。）上进行反振动核动力学，以对picsecond（PS = 10-12s。）时间表。例如，在光合作用中，叶绿素分子对紫外线的抽象诱导电子偶极振荡，其周期为1 fs，然后其较慢的衰变和能量再分配到核学位。在过去的几十年中，时间分辨光谱显示了很少有周期的飞秒激光脉冲可以用来指导核波包数据包并控制基本反应的结果。然而，缺乏较短的脉冲在亚振荡周期时间尺度出乎意料的情况下留下了对电子波数据包的控制。从电子偶极力启动核运动的最早时刻起，就可以遵循并最终更有效地控制反应动态吗？实际上，均可同时生产和与常见的桌面飞秒光学的光学技术同时生产并同步，均可同时生产并同步，均可同时生产和同步。最近的激光开发甚至将Attsend发射从XUV扩展到“水窗”软X射线（280-500EV）及以后。这项壮举从根本上偏离了迄今为止最短的皮秒脉冲，只有大规模（0.1-10公里）的加速器设施可用。水窗指定了水的光谱范围，其中水基本上与辐射是透明的，而碳和氮原子具有很高的吸收性；在水中实现了新型的高对比度，元素特异性，时间分辨光谱和纳米镜检查。结合我在时间分辨分子光谱法（渥太华大学，校长：Paul Corkum）方面的经验以及加拿大技术和光波形合成方面的独特专业知识（banting博士后学会（在Maxk-institut）在MAX-PLANCK-INSTITUT上用于量化量子的Quantum termics in Munich in Munich，Munich terme ter ter ter ter ter ter ter Ince terenc kra kra kra kra kra：kra kra kra：视觉：***通过实施光波形合成，可以通过意外时间和空间分辨率在水溶液中的生物分子的光谱法提供光学和水窗口柔软的X射线。 *** 2）在意外的Attosond机构中使用这种辐射将分子的光谱用于分子的光谱。