Quantum Gas Jet-based Helium Atom Microscope (qHAM)

传统的显微镜工具有许多局限性：光学显微镜本质上局限于微米左右的长度尺度;电子显微镜经常导致样品损坏或充电;扫描探针方法（如原子力显微镜）仅限于主要平坦表面上的小区域。这些限制给表面形态学研究带来了重大问题：诸如二维有机薄膜的精细样品有被高能电子束损坏的风险;更复杂的绝缘结构不能通过电子束以高分辨率成像，因为它们正在积累电荷;而传统的扫描探针技术如原子力显微镜（AFM）无法对具有复杂形貌的生物材料进行成像，本项目将利用两种量子现象：波-物二象性和物质波干涉来克服这些局限性。德布罗意布罗意波长？一个粒子的动量与它的动量p的关系是：h/p，其中h是普朗克常数。对于在室温下以热速度运动的氦原子，平均德布罗意布罗意波长为0.9埃。根据菲涅耳波带片（FZP）原理设计的原子筛在通过相邻区域行进的分子之间的路径差等于一个波长的点处实现聚焦。从这个条件，在焦点的半径可以推导出-这是非常小的，在微米范围内，使访问高分辨率成像。量子气体射流为基础的氦原子显微镜（qHAM）将开发为一个紧凑，低成本和台式显微镜具有上级成像能力。

Conventional microscopy tools have a number of limitations: Light microscopy is intrinsically 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.These limitations cause significant problems for surface morphological studies: delicate samples such as 2-dimensional organic thin films risk being damaged by energetic electron beams; more complex insulating structures cannot be imaged with high resolution by electron beams as they are accumulating charges; and bio-materials with complex topographies cannot be imaged by conventional scanning probe techniques such as Atomic Force Microscopy (AFM).This project will overcome these limitations by exploiting two quantum phenomena: Wave-Matter duality and matter wave Interference. The de Broglie wavelength ? of a particle is related to its momentum p by ?=h/p, where h is Planck's constant. For a helium atom moving with thermal velocity at room temperature, the average de Broglie wavelength is 0.9 Angstroem. An atom sieve designed on the principle of Fresnel Zone Plates (FZP) achieves a focus at the point where the path difference between molecules travelling via adjacent zones is equal to one wavelength. From this condition, the radius at the focal point can be derived - this extremely small and in the micrometer range, giving access to high resolution imaging.A quantum gas jet-based Helium Atom Microscope (qHAM) will be developed as a compact, low cost and table-top microscope with superior imaging capabilities.