  The previous theoretical study has shown that pulse irradiation to the Mott
insulating state in the Hubbard model can induce the enhancement of
superconducting correlation due to the generation of $\eta$ pairs. Here, we
show that the same mechanism can be applied to the Kondo lattice model, an
effective model for heavy electron systems, by demonstrating that the pulse
irradiation indeed enhances the $\eta$-pairing correlation. As in the case of
the Hubbard model, the non-linear optical process is essential to increase the
number of photoinduced $\eta$ pairs and thus the enhancement of the
superconducting correlation. We also find the diffusive behavior of the spin
dynamics after the pulse irradiation, suggesting that the increase of the
number of $\eta$ pairs leads to the decoupling between the conduction band and
the localized spins in the Kondo lattice model, which is inseparably related to
the photodoping effect.
