可编程电子光学的横向量子态表征
Transverse quantum-state characterization of programmable electron optics
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中文总结 AI 辅助
本研究通过混合态叠层衍射成像技术，利用四维STEM扫描对可编程电子光学的横向量子态进行表征，发现其纯度随偏压增大而降低，且可实现器件原位校准与剂量效率提升。
中文摘要 AI 辅助
可编程电子光学（电控相位板）支撑了从剂量效率相位成像到整形电子X射线源的各类方案，几乎所有方案都假设输出的是纯态、完全相干的出射波，但其纯度从未被测量过。本研究通过混合态叠层衍射成像技术，对微机电静电螺旋相位板的横向密度矩阵进行重建，每个状态仅需一次四维STEM扫描，无需额外硬件。实验发现，出射光束呈现显著的混合态特性：当施加偏压增大时，其纯度从约0.47降至约0.24，这与固定横向源模糊模型不符，而实空间相干宽度始终保持在1 nm附近。相同的扫描可对器件进行原位校准，实现虚拟轨道角动量排序，且通过考虑部分相干性的传递理论表明，纯化输出可将剂量效率提升约三倍。因此，单次采集即可作为可编程电子光学的量子态验收测试，提供新兴相位板和衍射成像方案所假设但未量化的纯度与相干性。
英文摘要
Programmable electron optics -- electronically controlled phase plates -- underpin proposals from dose-efficient phase imaging to shaped-electron X-ray sources, nearly all assuming a pure, fully coherent delivered wave whose purity has never been measured. Here we reconstruct the transverse density matrix of a microelectromechanical electrostatic spiral phase plate by mixed-state ptychography, from one four-dimensional STEM scan per state and without added hardware. The delivered beam is substantially mixed: its purity falls from approximately 0.47 to approximately 0.24 as the applied bias grows, inconsistent with a fixed lateral source-blur model, while the real-space coherence width stays near 1 nm. The same scans calibrate the device in situ, allow virtual orbital-angular-momentum sorting and, through a partial-coherence-aware transfer theory, indicate that purifying the output could improve dose efficiency roughly threefold. One acquisition thus becomes a quantum-state acceptance test for programmable electron optics, supplying the purity and coherence that emerging phase-plate and diffractive-imaging schemes assume but leave unquantified.
