  Photoinduced carrier dynamics in a correlated electron system on a coupled
two-leg ladder lattice are studied. The two-leg ladder Hubbard model is
analyzed by utilizing the exact diagonalization method based on the Lanczos
algorithm in finite size clusters. In order to reveal the transient carrier
dynamics after photoirradiation, we calculate the low-energy components of the
hole kinetic energy, the pair-field correlation function, the optical
conductivity spectra and others. It is shown that the photoinduced
metallic-like state appears in a half filled Mott insulating state, while the
low-energy carrier motion is suppressed by photoirradiation in hole doped
metallic states. These photoinduced changes in electron dynamics are associated
with changes in the carrier-pair coherence, and are not attributed to a naive
thermalization but to a ladder-lattice effect. Based on the numerical results,
optical controls of hole pairs by using the double-pulse pumping are
demonstrated. Implications to the recent optical pump-probe experiments are
presented.
