  We present experimental observations of strong electric and magnetic
interactions between split ring resonators (SRRs) in metamaterials. We
fabricated near-infrared (1.4 $\mu$m) planar metamaterials with different
inter-SRR spacings along different directions. Our transmission measurements
show blueshifts and redshifts of the magnetic resonance, depending on SRR
orientation relative to the lattice. The shifts agree well with a simple model
with simultaneous magnetic and electric near-field dipole coupling. We also
find large broadening of the resonance, accompanied by a decrease in effective
cross section per SRR with increasing density. These effects result from
superradiant scattering. Our data shed new light on Lorentz-Lorenz approaches
to metamaterials.
