论文标题
用非弹性电子散射探测手性
Probing chirality with inelastic electron-light scattering
论文作者
论文摘要
圆形二色性光谱是理解分子结构和磁性材料的必不可少的技术，但是空间分辨率受光的波长的限制，而灵敏度足以使单分子光谱法具有挑战性。我们证明，电子可以有效地测量具有深层分辨率的圆形极化光和手性材料之间的相互作用。通过扫描纳米尺寸的聚焦电子束跨光激发性手性纳米结构并在每个探针位置测量电子能谱，我们可以生成近场二分法的高空间分辨率图。该技术提供了基本对称性的纳米级视图，可以用作“光子染色”，以增加电子显微镜中的生物分子材料对比。
Circular dichroism spectroscopy is an essential technique for understanding molecular structure and magnetic materials, but spatial resolution is limited by the wavelength of light, and sensitivity sufficient for single-molecule spectroscopy is challenging. We demonstrate that electrons can efficiently measure the interaction between circularly polarized light and chiral materials with deeply sub-wavelength resolution. By scanning a nanometer-sized focused electron beam across an optically-excited chiral nanostructure and measuring the electron energy spectrum at each probe position, we produce a high-spatial-resolution map of near-field dichroism. This technique offers a nanoscale view of a fundamental symmetry and could be employed as "photon staining" to increase biomolecular material contrast in electron microscopy.
