Chiral metamaterials by shadowing vapor deposition

We report the fabrication of chiral metamaterials consisting of metal-coated columnar nano-arrays using a simple shadowing vapor deposition technique in which the shielding effect from the columnar arrays enables selective deposition on unshielded areas. Furthermore, the degree of shielding/shadowing among the arrays, and hence the handedness/chirality, can be controlled by adjusting the deposition angle with respect to the arrays. Using this technique we have fabricated quasi-3D metallic chiral metamaterials exhibiting very large circular dichroism in the optical range for circularly polarized incident light. The shadowing technique is very promising because it is simple, effective, and could be applied to the mass production of large sample size chiral metamaterials.