Nanodiamonds containing single tin-vacancy (SnV) centers have the potential for integration into nanophotonic devices employed in quantum technologies such as quantum sensing, quantum information processing and quantum communication. The present study assessed single SnV centers in nanodiamonds less than 10 nm in size. Such centers were generated by implanting Sn ions into size-selected small nanodiamonds followed by high-temperature annealing. A sharp emission peak with a line width of 2.6 nm was observed at 618.7 nm, corresponding to the zero phonon line of SnV centers in bulk diamond. The Debye–Waller factor for this peak at room temperature was estimated to be 0.38 and so was slightly greater than the value for bulk diamond. A second-order correlation function yielded a g 2 (0) value of 0.04 ± 0.11, indicating single-photon emission. The successful creation of single SnV centers in nanodiamonds is a critical step toward integrating nanophotonic devices for photonic quantum technologies.
Nanodiamonds containing single tin-vacancy (SnV) centers have the potential for integration into nanophotonic devices employed in quantum technologies such as quantum sensing, quantum information processing and quantum communication. The present study assessed single SnV centers in nanodiamonds less than 10 nm in size. Such centers were generated by implanting Sn ions into size-selected small nanodiamonds followed by high-temperature annealing. A sharp emission peak with a line width of 2.6 nm was observed at 618.7 nm, corresponding to the zero phonon line of SnV centers in bulk diamond. The Debye–Waller factor for this peak at room temperature was estimated to be 0.38 and so was slightly greater than the value for bulk diamond. A second-order correlation function yielded a g 2 (0) value of 0.04 ± 0.11, indicating single-photon emission. The successful creation of single SnV centers in nanodiamonds is a critical step toward integrating nanophotonic devices for photonic quantum technologies.
Group-IV color centers in diamonds are promising not only as spin-photon interfaces for quantum networks but also as multicolor photoluminescence probes and all-optical temperature sensors for biological research. Therefore, generating group-IV color centers in detonation nanodiamonds (DNDs), the smallest class of diamond nanocrystals, has become a research focal point. This approach holds potential for the noninvasive introduction of diamond sensors into living cell organelles, enabling sensing of local structural and temperature changes with minimal disturbance. Following the successful generation of silicon- and germanium-vacancy centers in DNDs, the generation of tin-vacancy (SnV) centers was investigated. Similar to other group-IV color centers, the SnV centers exhibit strong photoluminescence. In addition, the SnV center offers a long spin coherence time compared with those of silicon- and germanium-vacancy centers. However, the strain induced by large Sn atoms poses substantial challenges for generating SnV centers in ultrasmall nanodiamonds. In this study, Sn-doped DNDs with a mean particle size of ~ 5 nm were subjected to a 3 days boiling acid treatment, which led to sharp zero-phonon lines of SnV centers at ~ 620 nm in the photoluminescence spectra. Photon autocorrelation measurements further revealed the presence of single SnV centers in these DNDs.
Ultrasmall (about 10 nm), low-strain, artificially produced diamonds with an internal, active color center have substantial potential for quantum information processing and biomedical applications. Thus, it is of great importance to be able to artificially produce such diamonds. Here, we report on the high-pressure, high-temperature synthesis of such nanodiamonds about 10 nm in size and containing an optically active, single silicon-vacancy color center. Using special sample preparation technique, we were able to prepare samples containing single nanodiamonds on the surface. By correlating atomic-force microscope images and confocal optical images, we verified the presence of optically active color centers in single nanocrystals, and using second-order correlation measurements, we proved the single-photon emission statistics of these nanodiamonds. These color centers have nonblinking, spectrally narrow emission with narrow distribution of spectral width and positions of zero-phonon line, thus proving the high quality of the nanodiamonds produced.
Abstract Silicon vacancy (SiV) centers in diamonds have attracted much attention because of their stability and narrow emission linewidth, and are promising for applications in quantum information technology. SiV-center-encapsulated nanodiamonds have also attracted much attention because of their potential to be coupled to various photonic devices. One efficient way to fabricate nanodiamonds that contain SiV centers is Si ion implantation into nanodiamonds. However, the evaluation of a single SiV center in a nanodiamond produced by this method at low temperatures has not been performed. In this study, we report on the optical properties of a single SiV center in a nanodiamond produced by ion implantation at cryogenic temperatures. The emission spectrum from a single SiV center ( g 2 ( 0 ) = 0.19 ) was observed with four distinct fine splittings of the zero-phonon line (ZPL) at 4 K. At an excitation power of 50 μ W, the full width at half maximum of the ZPL reached the spectrometer resolution limit (0.09 nm). The temperature dependence of the emission peak is consistent with that of the emission coming from an SiV center under high strain. The results obtained in this work suggest that nanodiamonds containing single SiV centers formed using this method will be an important building block for the realization of quantum information applications.
Nanodiamonds containing color centers have been attracting attention as a hybrid system with nanophotonic devices to realize photonic quantum information devices such as highly efficient single photon sources. In various color centers, silicon vacancy (SiV) centers are especially interesting because of high photo-stability, high brightness, high Debye-Waller factor (about 70%), and lifetime-limited fluorescence linewidth. The nanodiamonds containing SiV centers have been usually fabricated by milling large nanodiamonds with SiV centers, which are synthesized by chemical vapor deposition (CVD). However, this milling method has an issue with the production yield. Here, we report on the fabrication of SiV centers inside nanodiamonds by direct implantation of Si ions, which allows the creation at a high production yield due to no requirement of the milling process. By implanting Si ions into nanodiamonds (median size of 25 nm), we fabricate SiV centers exhibiting a narrow linewidth of about 7 nm at room temperature. This linewidth is more than twice as narrow as previous reports on the implantation of Si ions into nanodiamonds.
Quantum networks rely on the efficient coupling of coherent quantum memories to photonic links. Tin-vacancy centers (SnV) have emerged as promising candidates for the implementation of an optically interfaced quantum memory based on their long spin coherence times at temperatures above 1K. To enhance their interaction with photons SnV centers need to be integrated with high-quality photonic structures. In this work, we report the enhancement of coherent emission of SnV centers by coupling them to a nanophotonic waveguide resonator. We observe strong intensity enhancement of the photon emission when the cavity is resonant with the color center. We demonstrate strong enhancement of the radiative recombination rate of SnV centers resulting in their predominant emission via the coherent zero-phonon line and into the cavity mode. These results are a significant step toward color-center-based quantum information processing applications without the need for dilution refrigerators.
The realization of quantum networks critically depends on establishing efficient, coherent light-matter interfaces. Optically active spins in diamond have emerged as promising quantum nodes based on their spin-selective optical transitions, long-lived spin ground states, and potential for integration with nanophotonics. Tin-vacancy (SnV-) centers in diamond are of particular interest because they exhibit narrow-linewidth emission in nanostructures and possess long spin coherence times at temperatures above 1 K. However, a nanophotonic interface for SnV- centers has not yet been realized. Here, we report cavity enhancement of the emission of SnV- centers in diamond. We integrate SnV- centers into one-dimensional photonic crystal resonators and observe a 40-fold increase in emission intensity. The Purcell factor of the coupled system is 25, resulting in channeling of the majority of photons (90%) into the cavity mode. Our results pave the way for the creation of efficient, scalable spin-photon interfaces based on SnV- centers in diamond.