title: Two-Photon Interference from the Far-Field Emission of Chip-Integrated Cavity-Coupled Emitters.
abstract: Interactions between solid-state quantum emitters and cavities are important for a broad range of applications in quantum communication, linear optical quantum computing, nonlinear photonics, and photonic quantum simulation. These applications often require combining many devices on a single chip with identical emission wavelengths in order to generate two-photon interference, the primary mechanism for achieving effective photon-photon interactions. Such integration remains extremely challenging due to inhomogeneous broadening and fabrication errors that randomize the resonant frequencies of both the emitters and cavities. In this Letter, we demonstrate two-photon interference from independent cavity-coupled emitters on the same chip, providing a potential solution to this long-standing problem. We overcome spectral mismatch between different cavities due to fabrication errors by depositing and locally evaporating a thin layer of condensed nitrogen. We integrate optical heaters to tune individual dots within each cavity to the same resonance with better than 3 μeV of precision. Combining these tuning methods, we demonstrate two-photon interference between two devices spaced by less than 15 μm on the same chip with a postselected visibility of 33%, which is limited by timing resolution of the detectors and background. These results pave the way to integrate multiple quantum light sources on the same chip to develop quantum photonic devices.
authors.affiliation: Department of Electrical and Computer Engineering and Institute for Research in Electronics and Applied Physics, University of Maryland , College Park, Maryland 20742, United States.
authors.forename: Je-Hyung
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Laboratory for Physical Sciences, University of Maryland , College Park, Maryland 20740, United States.
authors.forename: Christopher J K
authors.initials: CJ
authors.lastname: Richardson
authors.affiliation: Laboratory for Physical Sciences, University of Maryland , College Park, Maryland 20740, United States.
authors.forename: Richard P
authors.initials: RP
authors.lastname: Leavitt
authors.affiliation: Department of Electrical and Computer Engineering and Institute for Research in Electronics and Applied Physics, University of Maryland , College Park, Maryland 20742, United States.|Joint Quantum Institute, University of Maryland and the National Institute of Standards and Technology , College Park, Maryland 20742, United States.
authors.forename: Edo
authors.initials: E
authors.lastname: Waks
keywords: Two-photon interference; cavity integration; photonic crystal; quantum dots; single photon sources