Color centers within the diamond crystal lattice, where carbon atoms are replaced by different atoms, and adjacent lattice sites are empty, offer intriguing possibilities for solid-state quantum emitters. One of the most promising candidates is the nitrogen vacancy color center (NV) due to its bright single-photon emission and optically accessible spins. These properties make it a potential player in future quantum information processing and quantum networks. However, NVs face challenges related to efficient emission into the zero-phonon line (ZPL) necessary for producing indistinguishable photons.
Comparatively, quantum dots display great promise in emission properties but are restricted by coherence times in the tens of nanoseconds. This underscores the challenges in working with solid-state quantum emitters, particularly concerning single-photon generation and emitter spin coherence times.
Recent investigations into group IV vacancy centers in diamond, particularly SiV centers, present promising results addressing these challenges. Tin-based vacancy centers, in particular, exhibit favorable properties for integration into nanophotonic platforms, offering strong and stable zero-photon line emission in nanostructures.
Group IV vacancy centers in diamond benefit from excellent optical properties due to their crystallographic symmetry, favoring emission into the ZPL. SiV centers demonstrate coherence times of 10 ms at 100 mK, while SnV is predicted to achieve similar times at a readily accessible temperature of 2 K using a standard helium cryostat.
This mechanism allows for the generation of optical pulses with a nearly Gaussian shape, exhibiting a full-width-half-maximum as narrow as 280 ps. Additionally, the AWG-5064 is employed to drive an electro-optical phase modulator, facilitating the generation of frequency sidebands up to approximately 2 GHz. This capability enables the driving of two optical transitions with phase-stable laser fields.