Speaker
Description
The sequential resonant excitation of a 2-level quantum system results in the emission of a state of light showing time-entanglement encoded in the photon-number-basis. This notion can be extended to 3-level quantum systems as discussed in a recent proposal by Santoe et al. In this work, we report the experimental implementation of a sequential two-photon resonant excitation process of a solid-state 3-level system, constituted by the biexciton-, exciton-, and ground-state of a semiconductor quantum dot. The resulting light state exhibits entanglement in time and energy, encoded in the photon-number basis, which could be used in quantum information applications, e.g., dense information encoding or quantum communication protocols. Performing energy- and time-resolved correlation experiments in combination with extensive theoretical modeling, we are able to partially retrieve the entanglement structure of the generated state and extract an upper-bound for the fidelity to the entangled target state of $\mathcal{F} \leq 70\%$ before loss.
