Preparing single SiV⁻ center in nanodiamonds for external, optical coupling with access to all degrees of freedom

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.

A Robust Coherent Single-Photon Interface for Moderate- NA Optics Based on SiV Center in Nanodiamonds and a Plasmonic Bullseye Antenna

“…The AFM-based nanomanipulation enables later position optimization and dipole rotation. 34 The successful transfer into the bullseye structure is shown in figure 1 c) with an AFM scan resolving the positioned ND. The bullseye has a total diameter of around 20 µm, while the rings of the bullseye antenna have a height h = 80 nm, a period of P = 450 nm and a slit width a = 120 nm.…”

Prolonged orbital relaxation by locally modified phonon density of states for SiV$^-$ center in nanodiamonds

“…Outlook -The experimental results presented in this work show that the SiV − orbital lifetime is extended by a factor of 8 when incorporated into a small, tailored diamond host as compared to a SiV − in bulk-diamond. In order to suppress the orbital relaxation further, nanomanipulation techniques utilizing an AFM can be used to rotate the NDs, thereby lowering the area of contact which leads to a more optimal isolation [15,19]. In addition, using a substrate material which is engineered to suppress phonons in the relevant spectral range also reduces the impedance matching between the former and the ND, which yields a better isolated host.…”

“…Additionally, a weak 532 nm laser is utilized to stabilize the emission. T 1 is measured with a tailored pulse-sequence, consisting of several 200 ns-long pulses with an increasing inter-pulse delay τ [15]. The peak heights are extracted by summing up all counts within each pulse and subtracting the stationary ones.…”

Purcell-Enhanced Emission from Individual SiV$^-$ Center in Nanodiamonds Coupled to a Si$_3$N$_4$-Based, Photonic Crystal Cavity

“…Replacing the NV − center with the SiV − center could take advantage of the superior optical properties on the condition that above mentioned optical properties of the SiV − center also persist in small nanodiamonds. This, by itself non-trivial challenge, was solved in recent years demonstrating bulk-like optical and coherence properties of SiV − center in nanodiamonds [21,22] with the additional development of high-precision nanomanipulation tools [4,23]. The progress now lead to the ability to perform a post-processing procedure where all degrees of freedom of the coupling term to the SiV − center in NDs can be optimized [22].…”

“…This, by itself non-trivial challenge, was solved in recent years demonstrating bulk-like optical and coherence properties of SiV − center in nanodiamonds [21,22] with the additional development of high-precision nanomanipulation tools [4,23]. The progress now lead to the ability to perform a post-processing procedure where all degrees of freedom of the coupling term to the SiV − center in NDs can be optimized [22]. In this work we post-process a high-Q photonic crystal cavity (PCC) based on Si 3 N 4 which was optimized for quantum photonics applications with SiV − centers in NDs.…”