Forefront light source developments for ultrafast molecular imaging and table top x-ray science.

自1895年发现以来，X射线使人们对物质结构有了新的认识，这是以前用传统光学方法无法达到的。基于提供高空间分辨率的能力，来自各种科学领域的研究人员正在期待X射线脉冲以高时间分辨率探测动力学过程。这一探索激发了世界各地的X射线自由电子激光设施的建设，提供飞秒高亮度X射线脉冲。除了巨大的初始财务投资（数十亿美元）之外，缺点是可用性有限，限制了执行实验的数量。 因此，开展了密集的研究活动，以开发替代桌面飞秒X射线源。在先进激光光源，我们可以使用独特的基础设施，我的HQP将使用这些基础设施开发超快分子成像和桌面X射线科学的前沿光源，这些光源在分子，生物和材料科学中具有重要应用。我的研究活动建立在两个支柱上：（1）使用强烈的几个周期的0.8微米激光脉冲进行实时分子成像，以及（2）开发和应用强烈的几个周期的1.8微米脉冲用于超快软X射线科学。他们有着相同的长期目标，即实现高时空分辨率成像。 在此应用程序的背景下，我们将使用桌面技术，以飞秒和亚埃分辨率成像质子迁移。对这个过程进行成像对于物理化学具有重要意义，因为它发生在各种化学反应中。此外，我们将开发一个台式高通量超快软X射线源，使用高次谐波产生（HHG）的过程中的高空间分辨率成像和超快光谱研究在生物和材料科学。这需要开发1.8微米的TW峰值功率单周期激光源，以有效地将HHG扩展到keV光子能量，这将使桌面水窗X射线显微镜的开发成为可能，用于生物成像，并以阿秒时间分辨率进行超快退磁研究。

Since there discovery in 1895, X-rays lead to new insight in structure of matter previously inaccessible with conventional optical methods. Based on the ability to provide high spatial resolution, researchers from a broad diversity of scientific horizons are anticipating X-ray pulses to probe dynamical processes with high temporal resolution. This quest motivates the construction of X-ray Free Electron Laser facilities around the world providing femtosecond high brilliance X-ray pulses. There drawback besides a huge initial financial investment (billions of dollars) is limited availability, restraining the number of performed experiments. Thus, intense research activities to develop alternative table-top femtosecond X-ray sources are undertaken. At the Advanced Laser Light Source, we have access to unique infrastructures, which my HQPs will use to develop forefront light sources for ultrafast molecular imaging and table-top X-ray science with important applications in molecular, biological and material science. My research activities are founded on two pillars; (1) real-time molecular imaging with intense few-cycle 0.8 micron laser pulses, and (2) the development and application of intense few-cycle 1.8 micron pulses for ultrafast soft X-ray science. They share the same long term goal to enable high spatio-temporal resolution imaging. In the context of this application, we will use table-top techniques to image proton migration with femtosecond and sub-Angstrom resolution. Imaging this process is of high significance for physical chemistry as it occurs in a variety of chemical reactions. In addition, we will develop a table-top high flux ultrafast soft X-ray source using the process of high harmonic generation (HHG) for high spatial resolution imaging and ultrafast spectroscopic studies in biological and material science. This requires developing TW peak power single cycle laser source at 1.8 micron to efficiently scale HHG up to the keV photon energy, which will enable the development of a table-top water window X-ray microscope for biological imaging and to perform ultrafast demagnetization studies with attosecond temporal resolution.