On-chip time resolved detection of quantum dot emission using integrated superconducting single photon detectors

Abstract

We report the routing of quantum light emitted by self-assembled InGaAs quantum dots (QDs) into the optical modes of a GaAs ridge waveguide and its efficient detection on-chip via evanescent coupling to NbN superconducting nanowire single photon detectors (SSPDs). The waveguide coupled SSPDs primarily detect QD luminescence, with scattered photons from the excitation laser onto the proximal detector being negligible by comparison. The SSPD detection efficiency from the evanescently coupled waveguide modes is shown to be two orders of magnitude larger when compared with operation under normal incidence illumination, due to the much longer optical interaction length. Furthermore, in-situ time resolved measurements performed using the integrated detector show an average QD spontaneous emission lifetime of 0.95 ns, measured with a timing jitter of only 72 ps. The performance metrics of the SSPD integrated directly onto GaAs nano-photonic hardware confirms the strong potential for on-chip few-photon quantum optics using such semiconductor-superconductor hybrid systems.

A carrier relaxation bottleneck probed in single InGaAs quantum dots using integrated superconducting single photon detectors

“…To directly observe such relaxation bottleneck effects, superconducting single photon detectors (SSPDs) are suitable due to their near unity quantum efficiency and picosecond timing resolution 10,11 . Building up on recent progress in this field 12-14 , we developed highly efficient 15,16 NbNSSPDs on GaAs 17 and demonstrated the monolithic integration of InGaAs QDs as single photon emitters together with waveguides and detectors on a single chip 18 . In this letter, we compare photoluminescence (PL) dynamics recorded from a single dot with confocal off-chip detectors with on-chip PL using integrated SSPDs that provide temporal resolution better than 70 ps.…”

“…To correct for the energy dependent absorption stength, the power density P used for this experiment was converted into an energy independent population probability P X for a single exciton occupying the QD. Hereby, Poisson statistics 18,28 was used with P X = α · exp(−α), where α = P/P 0 and P 0 being the saturation power density, as extracted from the measurements presented in figure 2b. The results of these studies are presented in figure 4.…”

Deterministic separation of arbitrary photon pair states in integrated quantum circuits

“…(13)], can pose a challenge for stability. Recall that in HOM interference the impact of a non-zero time delay τ between interfering paths is primarily determined by the photon coherence time τ c ∝ 1/∆ω, which modulates the probability P S (τ, θ ) with a slowly-varying envelope [20].…”

Integrated autocorrelator based on superconducting nanowires

“…For advancing quantum photonics, the integration of optical components, such as single photon sources [1][2][3][4], passive circuit elements [5] and single photon detectors [6][7][8][9][10], within a quantum photonic integrated circuit (QPIC) is required in order to scale the system up to few tens of photons, which would be for example required to perform quantum simulations [11]. The measurement of the second-order correlation function g (2) (τ) and of the photon number is a key functionality for such a QPIC, allowing for example the characterization of single-and entangled-photon states [12].…”