  We investigate both experimentally and theoretically a simple yet more robust
and flexible alternative to Rabi oscillation-type biexciton preparation
protocols traditionally used for semiconductor quantum dots. The quantum dot is
excited by a strong laser pulse positively detuned from the two-photon
resonance yielding an on demand initialization of the biexciton state by making
use of the phonon-induced thermalization of the photon dressed states. It is
shown that for excitation pulses in the picosecond range, a stable and high
fidelity of up to $f_{XX}=0.98\pm 0.01$ is reached. Notably, the generated
photons show similar coherence properties as measured in the resonant
two-photon scheme. This protocol is a powerful tool for the control of complex
solid state systems combining radiative cascades, entanglement and resonant
cavity modes.
