Purcell enhancement of the silicon T centre

Synopsis

Quantum information technologies will be able to perform certain tasks that are intractable on classical computers, including chemically accurate simulations of heavy elements and large molecules, teleporting information, and cracking many modern cryptographic standards. While small scale demonstrations of these novel tasks exist, quantum processors require further scale up to realize the full potential of these applications. One way to scale quantum processors is through the use of quantum networks. Quantum networks allow for modularity by connecting multiple systems together using photons. To form a quantum network, one can make use of a spin-photon interface which stores quantum information in solid state spins and achieves connectivity via photons. Many spin-photon platforms depend on the use of optical cavities to achieve the rates of entanglement required to enable modularity. This is because optical cavities improve photon indistinguishability, a prerequisite for many entanglement schemes, by Purcell enhancing quantum emitters.  

Purcell enhancements of spin-photon interfaces have been demonstrated to date, but never for qubits native to silicon. Here we present the first report of Purcell enhancement of the T centre, a silicon-native spin-photon qubit. We do so by designing and fabricating a one-dimensional photonic crystal cavity with a quality factor of 40 000, mode volume of 2( λ /n)³ and resonant wavelength near the T centre optical transition. We observe an ensemble of cavity-coupled T centres by way of photoluminescence excitation spectroscopy and excited state lifetime measurements. We measure optical lifetime enhancements up to 9 and estimate a Purcell factor of 136. These results are an important step towards photonic engineering of the T centre for optical networks.