INSPIRE: Compact X-Ray Laser in "Water Window" and Microscopy of Cell Membranes

这个多学科的INSPIRE奖的最终目标是使一个新的，非常高分辨率的显微镜，能够看到内部的生物细胞使用的光比普通的可见光更有活力，但不如在传统的医学X射线使用的光能量。 具体而言，该项目旨在产生和使用“软X射线”光，在光的每次振荡（波长3.4和4.0 nm）期间，该光将传播3至4亿分之一米。 这些波长落在所谓的“水窗”（2.3-4.4 nm），其中水是透明的，但细胞的许多其他部分不是。 使用这些波长的光可以透过细胞内的水来清晰地看到细胞的功能部分。 关键的使能工具被称为X射线激光器（XRL），该项目旨在生产一种足够小且负担得起的激光器，以便广泛用于在自然环境中对活生物细胞进行成像。 这项工作是基于使用高电荷离子，原子的大部分电子被移除。 该项目的目标是通过成像自然细胞膜来展示新XRL的实用性。 这项工作由NSF综合活动办公室，原子，分子和光学实验物理计划，NSF/DOE基础等离子体科学和工程合作伙伴关系，生物研究计划仪器开发和生物学理事会新兴前沿办公室共同资助。高增益首次在复合X-这一结果激发了一种新的想法，即利用4.0nm的XRL与红外（IR）场直接在复合XRL的反转介质中。这个想法是在德克萨斯A M大学（TAMU）基于量子光学理论开发的，并在这里提出在普林斯顿实验测试这个想法，作为这个INSPIRE项目的一部分。预期用于生物成像的XRL的实际应用需要激光脉冲具有每个脉冲2 - 4微焦耳能量的能量。因此，该项目的关键问题将是寻找大的XRL光束强度放大。这种研究的自然延伸将是在另一个水窗口波长（在这种情况下为3.4nm）处产生高XRL光束强度。通过使用史瓦西多层涂层物镜和高灵敏度二维电荷耦合器件检测器，细胞辐射暴露将保持较低，以允许活细胞成像。

The ultimate goal of this multidisciplinary INSPIRE award is to enable a new, very high resolution microscope which is able to see inside biological cells by using light which is more energetic than ordinary visible light, but not as energetic as the light used in conventional medical x-rays. In specific, this project seeks to produce and use "soft x-ray" light that will travel between 3 and 4 billionths of a meter during each oscillation of the light (wavelengths 3.4 and 4.0 nm). These wavelengths fall in the so-called "water window" (2.3-4.4 nm) in which water is transparent, but many other parts of cells are not. Using light with these wavelengths allows one to see through the water inside cells to clearly visualize the functional parts of the cells in high resolution. The key enabling tool is called an X-ray laser (XRL), and this project seeks to produce one that is sufficiently small and affordable that it can be put into widespread use to image live biological cells in their natural environment. The work is based on the use of highly charged ions, atoms which have most of their electrons removed. Included in this project is the goal of demonstrating the utility of the new XRL by imaging natural cell membranes. This work is co-funded by the NSF Office of Integrative Activities, the Atomic, Molecular, and Optical Experimental Physics Program, the NSF/DOE Partnership in Basic Plasma Science and Engineering, the Instrument Development for Biological Research Program, and the Emerging Frontiers Office of the Biology Directorate.Recently, high gain was demonstrated for the first time in a recombination X-ray laser at 4.0nm This result stimulated a new idea to efficiently generate attosecond pulses by utilizing an XRL at 4.0 nm in combination with an infrared (IR) field directly in the inverted media of a recombination XRL. This idea was developed theoretically at Texas A&M University (TAMU) based on quantum optics and is proposed here to test this idea experimentally at Princeton as part of this INSPIRE project. It is expected that the practical application of an XRL for biological imaging requires the laser pulses to have an energy of 2 - 4 micro-Joules of energy per pulse. Therefore the crucial issue for this project will be the search for large XRL beam intensity amplification. The natural extension of this search will be the generation of high XRL beam intensity at another water window wavelength, in this case 3.4nm. By using a Schwarzschild multilayer coated objective and a high sensitivity two dimensional charge-coupled device detector, the cell radiation exposure will be kept low to allow the imaging of live cells.