  Coherent optical control of individual particles has been demonstrated both
for atoms and semiconductor quantum dots. Here we demonstrate the emergence of
quantum coherent effects in semiconductor Rydberg excitons in bulk Cu$_2$O. Due
to the spectral proximity between two adjacent Rydberg exciton states, a
single-frequency laser may pump both resonances with little dissipation from
the detuning. As a consequence, additional resonances appear in the absorption
spectrum that correspond to dressed states consisting of two Rydberg exciton
levels coupled to the excitonic vacuum, forming a V-type three-level system,
but driven only by one laser light source. We show that the level of pure
dephasing in this system is extremely low. These observations are a crucial
step towards coherently controlled quantum technologies in a bulk
semiconductor.
