Efficient extraction of photons from a NV center embedded in a diamond nanowire utilizing an optical nanofiber
Takao Aoki, Waseda University
NV centers in diamond have good optical properties and offer a wide variety of applications based on its interaction with photons, such as single-photon sources and quantum memories. One of the problems for such applications is efficient extraction of photons emitted by a NV center out of the diamond crystal, since the refractive index of a diamond is as high as 2.42. Here we propose a novel method for efficient extraction of photons from a NV center embedded in a diamond nanowire utilizing an optical nanofiber. When a diamond nanowire is attached to the surface of an optical nanofiber as schematically shown in the figure, the guided modes in the nanowire and the nanofiber form a set of supermodes. By utilizing the destructive interference of two supermodes at the end of the nanowire, the maximum coupling efficiency can reach as high as 75%[Y. Yonezu et al., Sci. Rep. 7, 12985 (2017)].