Collective Excitation of Spatio-Spectrally Distinct Quantum Dots Enabled by Chirped Pulses

For a scalable photonic device producing entangled photons, it is desirable to have multiple quantum emitters in an ensemble that can be collectively excited, despite their spectral variability. For quantum dots, Rabi rotation, the most popular method for resonant excitation, cannot assure a universal, highly efficient excited state preparation, because of its sensitivity to the excitation parameters. In contrast, Adiabatic Rapid Passage (ARP), relying on chirped optical pulses, is immune to quantum dot spectral inhomogeneity. Here, we advocate the robustness of ARP for simultaneous excitation of the biexciton states of multiple quantum dots. For positive chirps, we find that there is also regime of phonon advantage that widens the tolerance range of spectral detunings. Using the same laser pulse we demonstrate the simultaneous excitation of energetically and spatially distinct quantum dots. Being able to generate spatially multiplexed entangled photon pairs is a big step towards the scalability of photonic devices.