We are interested in developing integrated photonic technology based on single solid-state quantum emitters, focusing on performance maximization and creation of new functionality, to enable applications in quantum sciences. This investigation has two main research avenues.
In the first avenue, we are interested in is the development of heterogeneous integrated photonic devices based on single, self-assembled epitaxial III-V quantum dots. Such quantum dots are the most mature type of quantum emitters investigated to date , having been employed in high brightness sources of indistinguishable single-photons, spin-photon interfaces, and strongly coupled cavity quantum electrodynamic systems. We have demonstrated a number of nanophotonic devices that maximize coupling of single quantum dot single-photon emission to specific, engineered spatial photonic modes, enabling the creation of efficient free-space, fiber-coupled and on-chip waveguide-coupled single-photon sources. In particular, we have developed a heterogeneous integration platform that allows the creation of low-loss Si3N4-based integrated photonic circuits that incorporate GaAs nanophotonic geometries containing single InAs quantum dots. First demonstrations have included efficient quantum dot single-photon launch into Si3N4 waveguides, as well as observation of Purcell-type radiative rate enhancement . Devices fabricated with out platform profit from complementary, desirable optical properties offered by the III-V and Si3N4 materials, namely single-photon emission and low propagation losses, respectively. The potential landscape for further development using our hybrid platform is extremely rich. We are interested in (but not limited to) exploring topics such as: photonic quantum simulation with on-chip linear optics elements; quantum frequency conversion of quantum dot single photons using nonlinearities in Si3N4 or other materials; single dot strong coupling with hybrid, small mode-volume cavities; on-chip single-photon nonlinearities; on-chip electric control of quantum dot emission; incorporation of on-chip single-photon detectors; generation of waveguide-coupled entangled photon states; efficient on-chip spin-photon interfaces; cavity-enhanced Raman emission; on-chip single-photon wavepacket modulation; integration with relevant optical materials, such as lithium niobate or aluminum nitride. We expect that further development of our platform can , among other possibilities, enable significant scaling of linear-optics quantum photonic applications, such as photonic quantum simulation; enable creation of chip-scale, high-performance, certified and multifunctional quantum light sources; and enable probing of on-chip nonlinearities – such as optomechanical coupling and Kerr nonlinearities enhanced by nanophotonic structures- with quantum light.
While the technological maturity of epitaxial quantum dots currently allows development that can be applicable to quantum photonics in a shorter term, many promising types of quantum emitters have recently emerged, with optical properties and potential for photonic integration that can be either complementary or superior to those of quantum dots. As a second main research avenue, we are interested in developing heterogenous photonic integration technology to harness alternative single emitter systems such as organic dye molecules in organic crystalline hosts and defect emitters in 2D materials such as hBN and WSe2. Development of such technology will involve significant effort in photonic design, nanofabrication process development, optical materials and quantum integrated photonic device characterization.
 I. Aharonovich, D. Englund, D. & M. Toth, Solid-state single-photon emitters. Nat. Photonics 10, 631 (2016).
 M. Davanco, J. Liu, L. Sapienza, C.-Z. Zhang, J.V.M. Cardoso, V. Verma, R. Mirin, S. W. Nam, L. Liu & K. Srinivasan, Heterogeneous integration for on-chip quantum photonic circuits with single quantum dot devices, Nature communications 8 (1), 889 (2017)
single quantum emitters; photonic integration; quantum photonics; nanophotonics; single-photon sources; quantum dots; nanofabrication; photonic integrated circuits