Microscopy with neutral helium atoms: A wide-ranging new technique for delicate samples

显微镜在广泛的科学和技术领域中是至关重要的。然而，尽管有许多可用的技术，仍有许多材料是传统工具无法获得的：传统的光学显微镜仅限于微米左右的长度尺度；电子显微镜常常导致样品损坏或带电；扫描探针方法（如原子力显微镜）仅限于主要平面上的小区域。这些问题在精细材料的情况下尤为严重：例如，有机电子薄膜被高能电子损坏，或者精细的聚合物结构，其中充电会使图像模糊。这项提议的主要目的是开发一种革命性的新技术——扫描氦显微镜（SHeM）——利用中性原子的低能束产生图像，从而消除上述问题。这项新技术有很大的潜力，但必须提高其空间分辨率，并使非专业人员能够轻松地进行氦显微镜检查。通过利用他们开发的技术，申请人处于领导这些发展的理想位置。该研究计划旨在牢固地确立氦显微镜作为前沿研究工具的地位。主要的主题是：1。开发一种新型高分辨率显微镜，使其达到纳米级分辨率，成像速率可与扫描探针技术相媲美。这种新显微镜将使各种各样的新实验成为可能。它将适合非专业人员使用，并通过类似设施的访问模型提供给用户。通过开展广泛的合作实验，跨越多个应用领域，建立和促进氦显微镜的新兴领域。这将建立该技术的适用性，并有助于开发所需的成像模式，以优化各种原子表面散射机制产生的图像对比度。开发先进的图像采集和重建方法，包括利用自然图像的可压缩性，最大限度地减少采集时间，最大限度地提高在任何给定的实验期间可以获得的信息内容。通过首次将这种尖端算法应用于低信号扫描探针显微镜，我们预计这一主题的影响将远远超出目前的项目。该项目本质上是合作的：新的显微镜将在卡文迪什实验室（剑桥物理）开发和建造，由格拉斯哥材料物理小组的关键部件纳米制造提供支持。应用数学（剑桥）的研究人员将开发加速成像方法，而进一步的一系列国际合作者已同意提供样品，时间和专业知识，以探索不同领域的氦成像。在难以对精细样品成像的领域，氦气显微镜将对广泛的科学和技术领域产生影响。已经预见的应用包括半导体器件、复合材料、有机薄膜和MEMS器件中使用的高纵横比结构；但是这种新型显微镜的应用范围还没有得到充分的探索。该项目的成功将导致一种新的成像技术的商业化，英国将独特地利用这种技术的影响。

Microscopy is vitally important across a wide range of scientific and technological fields. However, despite the multitude of techniques available, there are many materials that are inaccessible to conventional tools: conventional light microscopy is limited to around micron length-scales; electron microscopy often leads to sample damage or charging; and scanning probe methods (such as atomic force microscopy) are limited to small areas on predominantly flat surfaces. Such problems are particularly acute in the case of delicate materials: for example, organic electronic thin films that are damaged by high-energy electrons, or fine polymer structures, where charging obscures the image.The main aim of this proposal is to develop a revolutionary new technique - Scanning Helium Microscopy (SHeM) - that generates images using a low-energy beam of neutral atoms and so obviates the above problems. The new technique has great potential, but it is essential to improve its spatial resolution and to make it possible for non-specialists to perform helium microscopy easily. The applicants are ideally positioned to lead these developments, by exploiting the technology they developed. The research programme is designed to firmly establish helium microscopy as a cutting-edge research tool. The main themes are:1. To develop a new high resolution microscope that will achieve nanoscale resolution and an imaging rate comparable with scanning probe techniques. The new microscope will make possible a wide range of new experiments. It will be suitable for use by non-specialists and made available to users through a facility-like access model.2. To establish and promote the nascent field of helium-microscopy by performing a broad range of collaborative experiments, spanning multiple applications. These will establish applicability of the technique, and help to develop the imaging modalities required to optimise image contrast arises from a variety of atom-surface scattering mechanisms.3. To develop advanced image collection and reconstruction methods, including making use of the compressibility of natural images, to minimise acquisition time and maximise the information content that can be obtained during any given experimental period. By applying such cutting-edge algorithms to a low-signal scanned probe microscopy for the first time, we anticipate the impact of this theme extending far beyond the present project.The programme is inherently collaborative: the new microscope will be developed and constructed at the Cavendish Laboratory (Physics, Cambridge), supported by nano-fabrication of key components in the Materials Physics group, Glasgow. Researchers in Applied Maths (Cambridge) will develop accelerated imaging methods, while a further series of international collaborators have agreed to provide samples, time and expertise, to explore helium imaging in a diverse range of fields.Microscopy with helium will have impact across a wide range of scientific and technological fields, wherever it is difficult to image delicate samples. Applications that are already foreseen include semiconductor devices, composite materials, organic films and the high aspect-ratio structures used in MEMS devices; but the scope for this new microscopy has yet to be fully explored. Success in the project will lead to the commercialisation of a new imaging technology, the impact of which the UK is uniquely positioned to exploit.