M. De Gregorio et al., Advanced Quantum Technologies, 7.10.1002/qute.202300227
The collection of single-photon emission from a quantum dot (QD) in a Bragg waveguide through a photonic wire bond (PWB) via free-space resonant frequency pumping at 1.6 K is demonstrated. The in-fiber single photons show a small multiphoton contribution, quantified by a low second order photon autocorrelation value of gcorr(2)(0)=(5.9±0.8)×10−3 (background-corrected) or graw(2)(0)=(9.5±1.4)×10−2(raw data). The decay time of the QD is measured to be τ=440 ps. The PWB obviates the need for in-cryostat alignment of the single-photon source with an optical fiber and thus offers a route to scalable integration of quantum photonic devices in a cryogenic environment. Uniquely, the approach combines the QD-waveguide technique, enabling resonant driving of individual QDs without the need for cross-polarization filtering, and the PWB for deterministic, alignment-free coupling of single-photon sources to optical fibers.
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