  The spatially-resolved laser-based high resolution ARPES measurements have
been performed on the optimally-doped $\mathrm{YBa_{2} Cu_{3} O_{7-\delta} }$
(Y123) superconductor. For the first time, we found the region from the cleaved
surface that reveals clear bulk electronic properties. The intrinsic Fermi
surface and band structures of Y123 are observed. The Fermi surface-dependent
and momentum-dependent superconducting gap is determined which is nodeless and
consistent with the d+is gap form.
