  We investigate the time evolution of optical conductivity in the half-filled
one-dimensional extended Hubbard model driven by a transient laser pulse, by
using the time-dependent Lanczos method. Photoinduced in-gap excitations
exhibit a qualitatively different structure in the spin-density wave (SDW) in
comparison to the charge-density-wave (CDW) phase. In the SDW, the origin of a
low-energy in-gap excitation is attributed to the even-odd parity of the
photoexcited states, while in the CDW an in-gap state is due to confined
photogenerated carriers. The signature of the in-gap excitations can be
identified as a characteristic oscillation in the time evolution of physical
quantities.
