Quantum Optics with Near-Lifetime-Limited Quantum-Dot Transitions in a Nanophotonic Waveguide

Abstract

Establishing a highly efficient photon-emitter interface where the intrinsic linewidth broadening is limited solely by spontaneous emission is a key step in quantum optics. It opens a pathway to coherent light-matter interaction for, e.g., the generation of highly indistinguishable photons, few-photon optical nonlinearities, and photon-emitter quantum gates. However, residual broadening mechanisms are ubiquitous and need to be combated. For solid-state emitters charge and nuclear spin noise are of importance, and the influence of photonic nanostructures on the broadening has not been clarified. We present near-lifetime-limited linewidths for quantum dots embedded in nanophotonic waveguides through a resonant transmission experiment. It is found that the scattering of single photons from the quantum dot can be obtained with an extinction of 66 ± 4%, which is limited by the coupling of the quantum dot to the nanostructure rather than the linewidth broadening. This is obtained by embedding the quantum dot in an electrically contacted nanophotonic membrane. A clear pathway to obtaining even larger single-photon extinction is laid out; i.e., the approach enables a fully deterministic and coherent photon-emitter interface in the solid state that is operated at optical frequencies.

Correlated dephasing noise in single-photon scattering

“…with pure dephasing rate γ f =σ 2 /κ. This is a well-known result, typically proven via the master equation formalism [61], which demonstrates that white pure noise dephasing maintains the natural Lorentzian lineshape of the qubit, while its width and depth get modified by γ f [3,11,59]. This Lorentzian behavior is shown by the blue/solid transmittance in figure 3(a), for typical waveguide QED parameters.…”

“…Finally, we would like to remark that the present derivation may be easily extended in various manners. So far we have considered a noisy qubit that is perfectly 'side-coupled' to the waveguide, but in experiments there may be impedance mismatches and internal reflections that cause Fano resonance in the scattering profiles [59,60]. Therefore, appendix B generalizes equations (24)-(25) for a noisy qubit with a Fano resonance and shows that the corresponding relations between transmission and reflection coefficients are still valid under correlated dephasing noise.…”

Suspended Spot‐Size Converters for Scalable Single‐Photon Devices

“…The data are fitted with two‐sided exponentials and the g (2) value is obtained by dividing the area of the central peak to the peak around a time delay of 250 ns on account of blinking over short timescales. The purity of the source could be improved even further by fabricating the structures on a sample with lower QD density or by adopting different excitation schemes such as p‐shell or resonant excitation …”

Generation of Non‐Classical Light Using Semiconductor Quantum Dots

“…For on‐chip applications such as integrated quantum photonic circuits, QDs are often integrated into waveguides rather than cavities . Here, photonic crystal W1 waveguides, which consist of one row of missing holes, have been used as well as photonic crystal glide‐plane waveguides, which allow for a chiral light–matter coupling, and nanobeam waveguides . Due to the efficient emission of QDs into the waveguide mode high source brightness in the waveguide can be realized.…”

“…The single photons can then be used on‐chip, for example, for quantum networks or efficiently coupled to single mode fibers . In addition to generating single photons using the schemes discussed above, nonlinear quantum optics can also result in the reflection of a coupled QD–single mode waveguide system to generate single photons through nonlinear quantum optics …”