Researchers have developed a novel Si-on-SiC photonic platform that enables efficient photon extraction from vanadium color centers in silicon carbide (SiC). These vanadium centers emit in the telecom O-band and exhibit sub-microsecond optical lifetimes and second-scale spin relaxation times, making them promising candidates for quantum network nodes. The main challenge until now has been the efficient extraction of photons from SiC, a material with a high refractive index. The new platform utilizes silicon nanocavities that evanescently couple to shallow vanadium dopants in commercial 4H-SiC, facilitating zero-phonon line (ZPL) collection under resonant excitation.

In as-grown vanadium ensembles, Purcell-enhanced photoluminescence was observed, with transient spectral hole burning linewidths of 50 MHz on microsecond timescales. In dilute implanted samples, scientists successfully isolated individual vanadium centers, demonstrating high-purity single photon emission and a Purcell-enhanced lifetime of 109 ns. The entire optical interface operates through a single lensed fiber, which includes a 905 nm repump laser capable of recovering the vanadium charge state with 95% efficiency.

These results represent a significant step towards the development of scalable, foundry-compatible spin-photon interfaces for telecom wavelengths. The Si-on-SiC platform offers a practical solution to overcome photon extraction limitations in high-refractive-index materials, opening new avenues for building robust and efficient quantum networks. The ability to integrate these components into existing manufacturing processes is crucial for future technological implementation.