  In this work, we consider a two-level system (TLS) coupled to a
one-dimensional continuum of bosonic modes in a transmission line. Using the
master equation approach, a method for determining the photon number
distribution of the scattered field is outlined. Specifically, results for the
reflected field when driving the TLS with a coherent pulse are given. While the
one-photon probability is enhanced compared to the incident coherent field, the
system is still not a good deterministic single-photon source. Extending the
system to contain two separate transmission lines, however, output fields with
one-photon probabilities close to unity can be reached.
