Southwest Quantum Information and Technology

Frequency control of single quantum emitters in integrated photonic circuits

Presenting Author: Emma Schmidgall, University of Washington
Contributing Author(s): Srivatsa Chakravarthi, Michael Gould, Ian Christen, Karine Hestroffer, Fariba Hatami, Kai-Mei Fu

An entangled graph state of qubits is a valuable resource for both universal quantum computation and quantum communication. To date, entanglement generation rates are too low to realize these multi-qubit networks due to photon emission into unwanted spatial and spectral modes. The integration of crystal defect-based qubits with photonic circuits can significantly enhance photon collection efficiency, albeit at the cost of degrading the defect's optical properties, such as an increase in inhomogeneous emission energies (linewidth broadening of GHz vs a few tens of MHz) and decreased spectral stability (spectral diffusion of tens of GHz vs a few hundred MHz). Compensating for this static and dynamic spread in emission energies is of critical importance for scalable on-chip graph state generation. We demonstrate the ability to tune the emission energy of photonic device-coupled near-surface NV centers over a large (200 GHz) tuning range with applied bias voltage. This is larger than the inhomogeneity of implanted NV centers suggesting a viable route for indistinguishable photons from separate emitters. However, measurements on many single waveguide-coupled NV centers highlight the variability in response to an applied bias voltage. Despite this variability, we are able to apply real-time voltage feedback control to partially stabilize the emission energy of a device-coupled NV center.

(Session 3 : Thursday from 2:15pm-2:45pm)