  We report on the coupling and interaction between the fundamental resonances
of planar metamaterials (split ring resonators) and inter-subband transitions
in GaAs/AlGaAs quantum wells structures in the mid-infrared. An incident field
polarized parallel to the sample surface is converted by the metamaterial
resonators into a field with a finite component polarized normal to the
surface, and interacts strongly with the large dipole moment associated with
quantum well inter-subband transitions.
