Relaxation of Photoinduced Quasi-Particles in Correlated Electron Metals

We present our studies of photoinduced quasi-particle dynamics in correlated electron metals. At room temperature, these materials exhibit metallic behavior characterized by the presence of a Fermi surface. Electronic correlations lead to a modification of the low-energy electronic structure near the Fermi level resulting in the opening of gaps or partial gaps due to such phenomena as density waves or superconductivity. We describe the results of optical pump-probe studies of quasi-particle dynamics in the spin density wave metal UNiGa
₅
, the heavy-fermion superconductor PuCoGa
₅
, and the pnictide high-temperature superconductor (Ba,K)Fe
₂
As
₂
.