# Preparing single SiV$^{-}$ center in nanodiamonds for external, optical coupling with access to all degrees of freedom

## TL;DR

This study demonstrates the preparation and manipulation of single silicon-vacancy centers in nanodiamonds, preserving their optical properties during nanomanipulation, enabling potential applications in quantum networks and integrated photonics.

## Contribution

We developed a method for preparing and nanomanipulating single SiV$^{-}$ centers in nanodiamonds while maintaining their optical properties, including rotation control and polarization analysis.

## Key findings

- Optical properties of SiV$^{-}$ centers are preserved during nanomanipulation.
- Nanodiamonds can be rotated, changing polarization contrast.
- High likelihood of indistinguishable single photon emission from different nanodiamonds.

## Abstract

Optical coupling enables intermediate- and long-range interactions between distant quantum emitters. Such interaction may be the basic element in bottom-up approaches of coupled spin systems or for integrated quantum photonics and quantum plasmonics. Here, we prepare nanodiamonds carrying single, negatively-charged silicon-vacancy centers for evanescent optical coupling with access to all degrees of freedom by means of atomic force nanomanipulation. The color centers feature excellent optical properties, comparable to silicon-vacancy centers in bulk diamond, resulting in a resolvable fine structure splitting, a linewidth close to the Fourier-Transform limit under resonant excitation and a good polarization contrast. We determine the orbital relaxation time $T_{1}$ of the orbitally split ground states and show that all optical properties are conserved during translational nanomanipulation. Furthermore, we demonstrate the rotation of the nanodiamonds. In contrast to the translational operation, the rotation leads to a change in polarization contrast. We utilize the change in polarization contrast before and after nanomanipulation to determine the rotation angle. Finally, we evaluate the likelihood for indistinguishable, single photon emission of silicon-vacancy centers located in different nanodiamonds. Our work enables ideal evanescent, optical coupling of distant nanodiamonds containing silicon-vacancy centers with applications in the realization of quantum networks, quantum repeaters or complex quantum systems.