Engineered birefringence positive-negative effective indices: Interferometric techniques and wedge experiment

The paper present an extraordinary transmission negative refractive index metamaterials. The authors show that they were able to keep the negative refractive index behaviour of the structure under vertical polarization by the insertion of vertical slits, while the horizontal polarization sees a positive index of refraction. Therefore, it is an unusual birefringent artificial structure, which may make significant contributions to many field likes polarization conversion or multiplexing/demultiplexing.