Confining photons to atomic length scales

将光子定位到原子长度尺度，在高分辨率扫描光学显微镜方面以及在强光-物质耦合方面提供了迷人的可能性。原子级分辨率的光谱成像预计将在生命科学以及一般的纳米科学中产生巨大的影响。另一方面，强耦合在纳米级光学谐振腔与原子尺度的模式体积将是巨大的兴趣，大规模集成的量子计算方案和实施的非线性全光数据操纵在单光子制度。然而，到目前为止，光定位已被限制在>10 nm的范围内。目前的项目将协同联合收割机两个突破性的方面，原子尺度的光定位，通过实施一种新型的扫描显微镜，使用原子限制MIM腔共振作为光学探针。我们最近成功地制作了单晶金属-绝缘体-金属（MIM）纳米谐振器与亚1 nm的绝缘间隙，并证明了相应的亚1 nm光限制。一方面，探针和/或样品的横向扫描将通过记录纳米物体（诸如单个量子点、（生物）分子和新型2D材料）的发光和拉曼散射来提供具有近原子空间分辨率的光谱映射。由于修改的选择规则，预计探测场的强梯度将打开多极光谱通道。另一方面，探针扫描也改变了探针和量子发射器之间的耦合强度，导致从微扰到强相互作用甚至可能是超强相互作用机制的平滑过渡。进一步的预期是，在强耦合机制中探针和量子发射体的量子力学纠缠将导致新的成像模式。

Localizing photons to atomic length scales offers fascinating possibilities in terms of high-resolution scanning optical microscopy, as well as in terms of strong light-matter coupling. Atomic-scale resolution spectroscopic imaging is expected to have a huge impact in life science as well as in nano science in general. On the other hand, strong coupling in a nanoscale optical resonator with atomic scale mode volume will be of great interest for large scale integration of quantum computation schemes and the implementation of nonlinearities for all-optical data manipulation in the single-photon regime. However, so far light localization has been limited to the >10 nm range. The present project will synergistically combine both groundbreaking aspects of atomic scale light localization by implementing a new type of scanning microscopy which uses atomically confined MIM cavity resonances as optical probes. We recently succeeded in fabricating single-crystal metal-insulator-metal (MIM) nano resonators with sub-1nm insulating gaps and demonstrated the corresponding sub-1nm light confinement. Lateral scanning of probe and/or sample on the one hand will afford spectroscopic mapping with near-atomic spatial resolution by recording luminescence and Raman scattering of nano objects, such as individual quantum dots, (bio)molecules, and novel 2D-materials. The strong gradients of the probe field are expected to open multipolar spectroscopic channels due to modified selection rules. On the other hand, probe scanning also varies the coupling strength between probe and quantum emitters, causing a smooth transition from the perturbative into the strong and possibly even ultrastrong interaction regime. It is further expected that the quantum mechanical entanglement of probe and quantum emitter in the strong coupling regime will lead to new imaging modalities.