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。这些限制给表面形态学研究带来了重大问题：精细的样品，如二维有机薄膜，有被高能电子束破坏的风险；更复杂的绝缘结构由于电荷积累，无法用电子束进行高分辨率成像；具有复杂地形的生物材料不能通过传统的扫描探针技术，如原子力显微镜（AFM）成像。该项目将通过利用两种量子现象：波-物质二象性和物质波干涉来克服这些限制。德布罗意波长？和它的动量p比？=h/p，其中h为普朗克常数。在室温下以热速度运动的氦原子，其平均德布罗意波长为0.9埃。利用菲涅耳带片（FZP）原理设计的原子筛，在通过相邻带的分子之间的路径差等于一个波长处实现聚焦。在这种情况下，在焦点的半径可以导出-这极小，在微米范围内，给予访问高分辨率成像。一种基于量子气体射流的氦原子显微镜（qHAM）将被开发为一种紧凑、低成本、具有优越成像能力的台式显微镜。

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.