Photo-reduction of metallic ions doped in patterned polymer films for the fabrication of plasmonic photonic crystals

Approaches for achieving large-area periodic, quasi-periodic, or even random structures at the nanometer-scale are important for promoting the development of nanophotonics. Mechanisms related to light-matter interactions have been involved in most of the nanofabrication methods. Photoreduction is one of the photochemical processes that have been employed in plasmonic nanopatterning, where metal ions are reduced to plasmonic nanoparticles. Here we demonstrate fabrication of plasmonic photonic crystals through photoreduction of silver ions doped in polymer films that are modulated by template gratings. Periodical arrays of continuous silver nanolines were produced after the subsequent liftoff and annealing processes performed on the reduced silver nanoparticles. Strong Fano-coupling between the plasmonic and photonic resonance modes not only verifies the success of this fabrication technique, but also enables exploiting new sensors and optoelectronic devices.