  We study quantum phases of ultracold bosonic atoms in a two-dimensional
optical superlattice. The extended Bose-Hubbard model derived from the system
of ultracold bosonic atoms in an optical superlattice is solved numerically
with Gutzwiller approach. We find that the modulated superfluid(MS),
Mott-insulator (MI) and density-wave(DW) phases appear in some regimes of
parameters. The experimental detection of the first order correlations and the
second order correlations of different quantum phases with time-of-flight and
noise-correlation techniques is proposed.
