Numerical simulations of nanodiamond nitrogen-vacancy centers coupled with tapered optical fibers as hybrid quantum nanophotonic devices

Abstract

Tapered optical fibers are promising one-dimensional nanophotonic waveguides that can provide efficient coupling between their fundamental mode and quantum nanoemitters placed inside them. Here, we present numerical studies on the coupling of single nitrogen-vacancy (NV) centers (single point dipoles) in nanodiamonds with tapered fibers. Our results lead to two important conclusions: (1) A maximum coupling efficiency of 53.4% can be realized for the two fiber ends when the NV bare dipole is located at the center of the tapered fiber. (2) NV centers even in 100-nm-sized nanodiamonds where bulk-like optical properties were reported show a coupling efficiency of 22% at the taper surface, with the coupling efficiency monotonically decreasing as the nanodiamond size increases. These results will be helpful in guiding the development of hybrid quantum devices for applications in quantum information science.

Highly Efficient Coupling of Nanolight Emitters to a Ultra-Wide Tunable Nanofibre Cavity

“…Numerical calculations indicate that this structure yields a mode volume as low as 0.7 μm 3 and that a large coupling efficiency of over 0.8 can be achieved (see Methods and Supporting Information)32. The corresponding electric field distribution is shown in Figure 1c while Figure 1d shows the calculated transmission spectrum.…”

Efficient photon coupling from a diamond nitrogen vacancy center by integration with silica fiber

“…Several research efforts have also sought to integrate quantum emitters directly with optical fibres, as a way of eliminating non-essential optical components and achieving compact and nearly monolithic interfaces. Recently, fluorescence collection from colloidal quantum dots and diamond nanocrystals containing single NVs was proposed [22,23] and demonstrated, often using a tapered fibre section [24][25][26][27][28][29]. However, these approaches use point-like emitters that exhibit poor collection efficiency; in addition, the spin and optical properties of NVs in diamond nanocrystals are degraded compared to bulk * rishipat@stanford.edu † schroder@mit.edu ‡ englund@mit.edu diamond [23].…”

Coupling of single NV center to adiabatically tapered optical single mode fiber

“…We came to a compromise regime, that allowed us to have up to 90% transmission through the fiber with ~450nm diameter and 5mm length waist (see Figure 1B). Fiber diameter was chosen based on prediction [24,25] with slight correction on broad emission spectrum of NV center. To estimate how broad spectrum will affect optimal fiber diameter we performed calculation for radial dipole located in the center of the fiber using finite-difference time-domain method (FDTD) with open source MEEP [26] software.…”

“…We found, that in comparison to the single frequency case the maximum of the coupling efficiency shifts towards bigger fiber diameter of 450 nm and has 20% smaller amplitude than in single frequency case. Accordingly to calculation performed at [24,25] this should translate in ¼ NV emission collected by the fiber for radially oriented dipole on the surface and at least factor of 3 less for axial. The last fact helps a lot to reduce the background fiber fluorescence that will be discussed below.…”