  We study the interplay of photons interacting with an artificial atom in the
presence of a controlled dephasing. Such artifical atoms consisting of several
independent scatterer can exhibit remarkable properties superior to single
atoms with a prominent example being a superatom based on Rydberg blockade. We
demonstrate that the induced dephasing allows for the controlled absorption of
a single photon from an arbitrary incoming probe field. This unique tool in
photon-matter interaction opens a way for building novel quantum devices and
several potential applications like a single photon transistor, high fidelity
n-photon counters, or for the creation of non-classical states of light by
photon subtraction are presented.
