Fig. 6.

Quantum dot-cavity coupling. a Photoluminescence (PL) spectra as a function of wavelength from a QD ensemble pumped with laser light at 975 nm, emitting inside three different GaAs microring resonators. Peaks are whispering gallery modes (WGMs) with quality factor Q, which increases with the microring-bus waveguide gap width. b PL spectrum for a single QD coupled to a Q ≈ 1.1 × 10⁴ WGM. Inset: fit of cavity-coupled QD emission near 1126 nm. c, Left: second-order correlation g ⁽²⁾(τ) for the 1126 nm exciton line in b. Right: close-up near τ = 0. Circles are experimental data, red lines are a fit. The blue curve and quoted g ⁽²⁾(0) are obtained from the red fit by deconvolving the detection time-response. d PL spectrum for a single QD in a microring, coupled to a Q ≈ 6 × 10³ WGM. Circles: experimental data. Blue continuous line: fit. Dashed lines: fitting Lorentzians for the cavity and two excitons, X₁ and X₂. e g ⁽²⁾(τ) for X₁ in d. Inset: close-up near τ = 0. f, Left panel: PL spectra for varying spectral detuning Δ between X₁ and the cavity. Δ is obtained from fits as in d. All spectra are normalized to the intensity maximum at Δ ≈ −0.07 nm. The color scale indicates normalized intensity. Right panel: corresponding X₁ photoluminescence decay curves. Gray dots are experimental data, red (blue) lines are biexponential (monoexponential) decay fits. For biexponential fits, τ ₁ is the fast lifetime. g, Left panel: integrated intensity as a function of Δ for the filtered X₁ exciton contribution to the the PL spectra in f, obtained from Lorentzian fits as in d, normalized by the integrated intensity of the full fitted spectrum. Right panel: decay lifetimes for the fits in f, as a function of Δ. Open blue circles are the fast biexponential decay lifetimes, closed blue circles are the monoexponential decay lifetimes. Uncertainties for g ⁽²⁾(0), Δ and the X₁ magnitude are 95% fit confidence intervals (two standard deviations). Lifetime uncertainties are single standard deviations from the exponential decay fits