Form birefringence metal and its plasmonic anisotropy

We constructed a uniaxial form birefringence metal that exhibits different dielectric polarizabilities along different optical axes as well as its supported optical anisotropy of surface plasmon polariton waves. The generated plasmonic index ellipsoid that exists in reciprocal space has been directly mapped and characterized in our experiment. The discovery of this anisotropic plasmonic metamaterial further completes analogy between artificial plasmonic metamaterials and conventional optical crystals, thereby providing opportunities to miniaturize myriad existing optical devices on-a-chip with plasmonics into nanometers scale.