  Resonant excitation of solid state quantum emitters has the potential to
deterministically excite a localized exciton while ensuring a maximally
coherent emission. In this work, we demonstrate the coherent coupling of an
exciton localized in a lithographically positioned, site-controlled
semiconductor quantum dot to an external resonant laser field. For strong
continuous-wave driving we observe the characteristic Mollow triplet and
analyze the Rabi splitting and sideband widths as a function of driving
strength and temperature. The sideband widths increase linearly with
temperature and the square of the driving strength, which we explain via
coupling of the exciton to longitudinal acoustic phonons. We also find an
increase of the Rabi splitting with temperature, which indicates a temperature
induced delocalization of the excitonic wave function resulting in an increase
of the oscillator strength. Finally, we demonstrate coherent control of the
exciton excited state population via pulsed resonant excitation and observe a
damping of the Rabi oscillations with increasing pulse area, which is
consistent with our exciton-photon coupling model. We believe that our work
outlines the possibility to implement fully scalable platforms of solid state
quantum emitters. The latter is one of the key prerequisites for more advanced,
integrated nanophotonic quantum circuits.
