Tashima Toshiyuki, Takashima Hideaki, Takeuchi Shigeki
Opt Express. 2019 Sep 16;27(19):27009-27016. doi: 10.1364/OE.27.027009.
Direct optical excitation of a nitrogen-vacancy (NV) center in nanodiamond by light via a nanofiber is of interest for all-fiber-integrated quantum applications. However, the background light induced by the excitation light via the nanofiber is problematic as it has the same optical wavelength as the emission light from the NV center. In this paper, we propose using a nanofiber Bragg cavity to address this problem. We numerically simulate and estimate the electric field of a nanodiamond induced by excitation light applied from an objective lens on a confocal microscope system, a nanofiber, and nanofiber Bragg-cavities (NFBCs). We estimate that by using a nanofiber, the optical excitation intensity can be decreased by roughly a factor of 10 compared to using an objective lens, while for an NFBC with a grating number of 240 (120 for one side) on a nanofiber the optical excitation intensity can be significantly decreased by roughly a factor of 100. This reduction of optical excitation intensity will make it possible to distinguish the fluorescence of the NV center from the background light.
通过纳米纤维利用光直接光学激发纳米金刚石中的氮空位（NV）中心，对于全光纤集成量子应用具有重要意义。然而，通过纳米纤维的激发光所诱导的背景光存在问题，因为它与NV中心发射光具有相同的光学波长。在本文中，我们提出使用纳米纤维布拉格腔来解决这一问题。我们对共焦显微镜系统中由物镜施加的激发光、纳米纤维以及纳米纤维布拉格腔（NFBC）所诱导的纳米金刚石的电场进行了数值模拟和估算。我们估计，与使用物镜相比，使用纳米纤维时光学激发强度可降低约10倍，而对于在纳米纤维上具有240个光栅（一侧120个）的NFBC，光学激发强度可显著降低约100倍。这种光学激发强度的降低将使得能够从背景光中区分出NV中心的荧光。
