  We demonstrate deterministic and robust generation of pulsed resonance
fluorescence single photons from a single InGaAs quantum dot using the method
of rapid adiabatic passage. Comparative study is performed with
transform-limited, negatively chirped and positively chirped pulses,
identifying the last one to be the most robust against fluctuation of driving
strength. The generated single photons are background free, have a vanishing
two-photon emission probability of 0.3% and a raw (corrected) two-photon
Hong-Ou-Mandel interference visibility of 97.9% (99.5%), reaching a precision
that places single photons at the threshold for fault-tolerant surface-code
quantum computing. The single-photon source can be readily scaled up to
multi-photon entanglement and used for quantum metrology, boson sampling and
linear optical quantum computing.
