基于金刚石表面氮-空位色心高荧光收集效率结构的研究

Room temperature solid state single spin quantum information technology is an emerging frontier. The superior properties of the point-defect nitrogen-vacancy (NV) color center in diamond has been extensively studied in the field of single-spin quantum computation at room temperature and quantum precision measurement. The NV center has coherence times on the order of milliseconds at room temperature and the initiation, manipulation and readout of its single electron spin states can be achieved by laser excitation and microwave pulses. Fluorescence photon detection efficiency is one of the main problems that restricts its application. Due to the very high refractive index of diamond, total internal reflection occurs when fluorescence is emitted from the interior of the diamond to the air, resulting in a photon collection efficiency of less than 3%. By micro-nano processing of the contact surface between diamond and air, the total reflection effect on the surface is greatly weakened, which can effectively improve the collection efficiency of fluorescence. Based on Finite Difference Time Domain simulation and micro/nano processing, this project proposes a new surface processing method for diamond to enhance the fluorescence collection efficiency of diamond NV center to a leading international level and to develop a complete set of diamond micro-nano processing method. The prepared diamond optical structure will play a key role in the room temperature solid state single spin quantum information technology.

室温固态单自旋量子信息技术是新兴的前沿领域。金刚石中的点缺陷氮-空位（NV）色心在室温下就具有毫秒量级的相干时间，并可以通过激光激发和微波脉冲实现单电子自旋态的初始化、操控和读出，其以这些优越的性质在室温固态单自旋量子计算以及量子精密测量等方面被广泛深入的研究。荧光光子探测效率是制约其上述应用的主要问题之一。由于金刚石折射率非常高，荧光从金刚石内部出射至空气时，表面上会发生全反射，导致光子的收集效率不到3%。通过对金刚石与空气接触表面进行微纳加工，让表面上的全反射效应大大减弱，可以有效的改善荧光的收集效率。本项目将基于Finite Difference Time Domain仿真和微纳加工的手段，提出新型金刚石的表面加工方案，提升金刚石NV色心的荧光收集效率至国际领先水平，并在这一过程中研发一套完整的金刚石微纳加工的方法。制备得到的金刚石光学结构将对室温固态单自旋量子信息技术起到关键作用。

金刚石中的点缺陷氮-空位（NV）色心具有室温下毫秒量级的相干时间，并可以通过激光激发和微波脉冲实现单电子自旋态的初始化、操控和读出。因此，其在室温固态单自旋量子计算以及量子精密测量等研究领域有着至关重要的意义。然而NV色心的荧光读出效率低(3%)制约了其在上述领域中的应用。本课题通过对金刚石与空气接触表面进行微纳加工，让表面上的全反射效应大大减弱从而有效改善金刚石内NV色心出射荧光的收集效率。本项目通过Finite Difference Time Domain仿真设计优化金刚石中NV色心高荧光收集效率微纳光学结构并通过微纳加工的手段，实现固体浸没透镜和纳米柱型的NV色心高荧光收集效率微纳光学结构。通过其有效结合我们将金刚石NV色心的荧光收集效率提升至国际领先水平。在此过程中我们研发一套完整的金刚石微纳加工的方法并将制备得到的金刚石光学结构应用于单分子磁共振测量和生物分子磁成像等研究领域。本研究将对室温固态单自旋量子信息技术的发展起到关键作用。