Quantum Optics with SiV Centers
Our work combines the study of color centers and nanophotonics to explore quantum optics and quantum cavity electrodynamics. We build systems to control the interaction between light and atom-like systems at the nanoscale, with diverse applications in quantum communication and quantum information processing.
The key component of this work is the negatively-charged Silicon Vacancy (SiV-) color center in diamond, a point defect characterized by the replacement of two adjacent carbon atoms with a single silicon atom. SiVs are bright, narrowband, optical emitters, with optically addressable spin transitions stable against background electric field noise. At temperatures below 300 mK, the SiV has a long-lived spin degree of freedom that enables its use as a qubit.
In our work, SiVs are placed into diamond nanophotonic crystal cavities. The combination of indistinguishable quantum emitters and a cavity environment that can confine these photons allows for powerful exploration of quantum physics and technology. Specifically, this system can act as an efficient and tunable source of single photons, a controllable environment within which the photons and SiVs can interact with themselves and each other, and channels that output information about these interactions, in the form of light, to outside observers (us!).
This highly controllable platform has enabled exploration of SiVs as qubits for quantum computers, generating the first entangled solid-state qubit in a nanophotonic device, as well as demonstration of SiVs as single photon switches for quantum communication, and mediation of interactions between multiple SiVs in the same nanodevice to study quantum many-body physics with light. These results demonstrate potential for using SiVs to achieve record-breaking spin-photon entanglement generation rates, quantum switching between multiple photons, scalable entanglement between different nanodevices, as well as the possibility of probing new physics by incorporation of phonons through optomechanics and spin-phonon coupling.