Laser Patterning of Plasmonic Gold and Silver Nanoband Arrays

Plasmonic metal nanoband arrays were fabricated by scanning Au or Ag films on dielectric or semiconducting substrates such as TiO ₂ with a cost‐effective near‐infrared laser marking system. Surface plasmon polaritons were excited through localized surface plasmons at the metal surface with nanoscale roughness, leading to periodic array formation. The nanoband period was controlled by selecting metals and underlying dielectric materials with appropriate dielectric constants. Because the arrays appeared only in the laser‐scanned regions, arbitrary patterns of nanoband arrays were easily produced. The resulting arrays and patterns exhibited brilliant visible light diffraction as plasmonic gratings, indicating potential applications to security printing for anticounterfeiting and certification, as well as other optical devices.