  The complex optical properties of the iron-chalcogenide superconductor
FeTe0.55Se0.45 with Tc=14K have been examined over a wide frequency range for
light polarized in the Fe-Te(Se) planes above and below Tc. At room temperature
the optical response may be described by a weakly-interacting Fermi liquid;
however, just above Tc this picture breaks down and the scattering rate takes
on a linear frequency dependence. Below Tc there is evidence for two gap
features in the optical conductivity at Delta_1 ~ 2.5 meV and Delta_2 ~ 5.1
meV. Less than 20% of the free carriers collapse into the condensate for T <<
Tc, and this material is observed to fall on the universal scaling line for a
BCS dirty-limit superconductor in the weak-coupling limit.
