  A coherent electromagnetic field can be described by its amplitude,
frequency, and phase. All these properties can influence the interaction
between the field and an atom. Here we demonstrate the phase shaping of
microwaves that are scattered by a superconducting artificial atom coupled to
the end of a semi-infinite 1D transmission line. In particular, we input a weak
exponentially rising pulse with phase modulation to a transmon qubit. We
observe that field-atom interaction can be tuned from nearly full interaction
(interaction efficiency, i.e., amount of the field energy interacting with the
atom, of 94.5%) to effectively no interaction (interaction efficiency 3.5%).
