  The galaxy intrinsic alignment causes the galaxy ellipticity-ellipticity
power spectrum between two photometric redshifts to decrease faster with
respect to the redshift separation $\Delta z^P$, for fixed mean redshift. This
offers a valuable diagnosis on the intrinsic alignment. We show that the
distinctive dependences of the GG, II and GI correlations on $\Delta z^P$ over
the range $|\Delta z^P|\la 0.2$ can be understood robustly without strong
assumptions on the intrinsic alignment. This allows us to measure the intrinsic
alignment within each conventional photo-z bin of typical size $\ga 0.2$,
through lensing tomography of photo-z bin size $\sim 0.01$. Both the
statistical and systematical errors in the lensing cosmology can be reduced by
this self-calibration technique.
