  We propose a scheme for the generation of highly indistinguishable single
photons using semiconductor quantum dots and demonstrate its performance and
potential. The scheme is based on the resonant two-photon excitation of the
biexciton followed by stimulation of the biexciton to selectively prepare an
exciton. Quantum-optical simulations and experiments are in good agreement and
show that the scheme provides significant advantages over previously
demonstrated excitation methods. The two-photon excitation of the biexciton
suppresses re-excitation and enables ultra-low multi-photon errors, while the
precisely timed stimulation pulse results in very low timing jitter of the
photons, and consequently, high indistinguishability. Since both control laser
fields are detuned from the emission energy, the scheme does not require
polarization filtering, facilitating high brightness approaching unity.
Moreover, the polarization of the emitted single photons is controlled by the
stimulation laser field, such that the polarization of the quantum light is
deterministically programmable.
