  Correlations between the magnification or polarization of background sources,
induced by gravitational lensing due to the large-scale structure, and the
positions of foreground galaxies are investigated. We found that their
amplitude is enhanced with respect to correlations for a single population. We
analize the dependence of the correlations with the density parameter \Omega
considering a nonlinear evolution of the matter power spectrum. The
contribution of the linear evolution is negligible at scales below several
arcminutes. Detailed results on the dependence of the correlations on the
redshift of the foreground and background populations for different
cosmological models are presented. The effect reaches its maximum amplitude for
foreground populations with relatively small redshifts due to the fast increase
of the nonlinear matter power spectrum at recent times.
