A biexciton in a semiconductor quantum dot is a source of
polarization-entangled photons with high potential for implementation in
scalable systems. Several approaches for non-resonant, resonant and
quasi-resonant biexciton preparation exist, but all have their own
disadvantages, for instance low fidelity, timing jitter, incoherence or
sensitivity to experimental parameters. We demonstrate a coherent and robust
technique to generate a biexciton in an InGaAs quantum dot with a fidelity
close to one. The main concept is the application of rapid adiabatic passage to
the ground state-exciton-biexciton system. We reinforce our experimental
results with simulations which include a microscopic coupling to phonons.Comment: Main manuscript 5 pages and 4 figures, Supplementary Information 5
pages and 3 figures, accepted as a Rapid Communication in PRB. arXiv admin
note: text overlap with arXiv:1701.0130
