Three‐Dimensional Bichiral Plasmonic Crystals Fabricated by Direct Laser Writing and Electroless Silver Plating

Direct laser writing and subsequent electroless silver plating is introduced as a high‐quality fabrication method for three‐dimensional plasmonic nanostructures. With this method, we fabricate the first three‐dimensional bichiral plasmonic crystals, which exhibit a large difference in transmittance of left‐handed and right‐handed circularly polarized light in the mid‐infrared spectral region between 3 and 5 μm. Our structure has a high degree of isotropy, showing only a weak dependence of the transmittance on the angle of incidence.