Coherent properties of a tunable low-energy electron-matter-wave source
Coherent properties of a tunable low-energy electron-matter-wave source
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DOI：
10.1103/physreva.97.013611
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发表时间：
2018-01-12
影响因子：
2.9
通讯作者：
Stibor, A.
中科院分区：
文献类型：
--
作者：
Pooch, A.;Seidling, M.;Stibor, A.
各种量子实验和应用中的普遍挑战是开发合适的相干粒子源。特别是，显微镜、干涉测量、计量、退相干测量和基于芯片的应用的最新进展依赖于自由低能电子物质波的密集、可调谐、相干源。在大多数情况下，电子从金属纳米尖端发射场，其半径和朝向反电极的几何形状决定了场分布和发射电压。较高的发射通常与具有较小德布罗意波长的较快电子相关，在物质波衍射或干涉测量后需要较大的图案放大倍数。这可以通过由两个反电极组成的众所周知的装置来防止，该装置允许独立设置光束强度和速度。然而，需要测试这种源的相干特性在电子加速和减速后是否保持不变。在这里，我们研究了如果粒子速度和波长在发射后发生变化的情况下，具有单原子尖端电子场发射器的双棱镜干涉仪中光束的相干性。通过维恩滤波器测量和对比相关分析，我们证明在不改变电子束横向和纵向相干性的情况下，特定粒子波长下的源强度可以增强至 6.4 倍。此外，测得单原子尖端发射器的能量宽度为377 meV，对应于82 nm的纵向相干长度。该设计在干涉测量、显微镜和传感器技术方面具有潜在的应用。
A general challenge in various quantum experiments and applications is to develop suitable sources for coherent particles. In particular, recent progress in microscopy, interferometry, metrology, decoherence measurements, and chip-based applications rely on intensive, tunable, coherent sources for free low-energy electron-matter waves. In most cases, the electrons get field emitted from a metal nanotip, where its radius and geometry toward a counter electrode determines the field distribution and the emission voltage. A higher emission is often connected to faster electrons with smaller de Broglie wavelengths, requiring larger pattern magnification after matter-wave diffraction or interferometry. This can be prevented with a well-known setup consisting of two counter electrodes that allow independent setting of the beam intensity and velocity. However, it needs to be tested if the coherent properties of such a source are preserved after the acceleration and deceleration of the electrons. Here, we study the coherence of the beam in a biprism interferometer with a single atom tip electron field emitter if the particle velocity and wavelength varies after emission. With a Wien filter measurement and a contrast correlation analysis we demonstrate that the intensity of the source at a certain particle wavelength can be enhanced up to a factor of 6.4 without changing the transverse and longitudinal coherence of the electron beam. In addition, the energy width of the single atom tip emitter was measured to be 377 meV, corresponding to a longitudinal coherence length of 82 nm. The design has potential applications in interferometry, microscopy, and sensor technology.