Metal-nanoshelled three-dimensional photonic lattices

Micronanostructures prepared by two-photon photopolymerization are utilized as templates for electroless plating of metals, giving rise to an approach for fabricating complex-shaped metal micronanostructures that are so far not achievable by other means. We show that when the coated-layer thickness of a metal coating is larger than a critical value (around 20 nm for silver at 2-3 microm wavelength) associated with the metal's skin depth, the photonic crystals exhibit optical properties more comparable to a solid metal structure than to their polymer counterparts.