Three-dimensional quantum photonic elements based on single emitters in laser-written microstructures for efficient non-classical light generation and ultra-sensitive optical nanomagnetometry

该项目的目标是证明高效的非经典光产生和超灵敏的光学纳米磁测量是新型三维纳米光子结构的两个关键功能，这是一种独特的、高度通用的技术。该方法是利用纳米金刚石中的颜色缺陷中心作为单一稳定的量子系统，以及通过按需直接激光写入（DLW）制造的介电和金属纳米结构。色心是氮空位（NV）缺陷，它一方面是单光子的来源。另一方面，其电子自旋态的光学读出可以用作具有高灵敏度和纳米空间分辨率的局部磁强计。本项目首次为几乎任意量子光子元件提供了一种可靠且经济的组装方法。该制造方案易于实施，不需要复杂的洁净室环境。它克服了基于多层或膜的现有方法的局限性，并引入了在基本量子水平上使用单光子或利用单自旋的真正三维结构。此外，我们力求首次在一个集成平台中结合多种功能。例如，基于谐振器或等离子体的光收集增强，用于改善光学自旋读出或微流体电池中单自旋磁力计的集成。在我们的项目中，两个小组加入了他们互补的专业知识，即洪堡大学（HUB）集成纳米系统和单光子物理学的量子光学测量，以及卡尔斯鲁厄理工学院（KIT）的纳米光子学和直接激光书写技术。

The goal of this project is to demonstrate efficient non-classical light generation and ultra-sensitive optical nanomagnetometry as two key functionalities of novel three-dimensional nanophotonic structures realized with a unique and highly versatile technology. The approach is to utilize a color defect center in a nanodiamond as a single stable quantum system together with dielectric and metallic nano-architectures fabricated by on-demand direct laser writing (DLW). The color center is a nitrogen-vacancy (NV) defect which on the one hand is a source of single photons. On the other hand optical read-out of its electron spin state can be used as a local magnetometer with high-sensitivity and nanometer spatial resolution.Our project introduces for the first time a reliable and cost-efficient assembly method for almost arbitrary quantum photonic elements. The fabrication scheme is easy to implement and requires no elaborate clean-room environment. It overcomes the limit of established approaches based on multi-layers or membranes and introduces true three-dimensional structures operating at the fundamental quantum level with single photons or exploiting single spins. Moreover, we strive to combine multiple functionalities in an integrated platform for the first time. Examples are resonator or plasmon-based enhancement of light collection for improving optical spin read-out or integration of single spin magnetometers in a microfluidic cell.In our project two groups join their complementary expertise which is quantum optical measurements in integrated nanosystems and single photon physics at Humboldt-University (HUB) as well as nanophotonics and direct laser writing technology at the Karlsruhe Institute of Technology (KIT).