Spin-cast thin silver film via transparent silver ink and its application: Nano-imprinted Bragg gratings for long-range surface plasmon polaritons

Thin silver films of 20 nm thickness were fabricated via spin-casting of a transparent silver ink at low temperature (130°C) in the absence of a vacuum system. The characterization of the spin-cast thin silver film is compared with that of thermally evaporated silver film. For a practical application of the transparent silver ink, long-range surface plasmon polariton waveguides based on Bragg gratings (LRSPPW-BGs) were designed and fabricated. For 20 nm thick, 8 μm wide and more than 500 μm long LRSPPW-BGs, the measured reflectances are more than 90% at Bragg wavelengths of ~1532 nm. The use of transparent silver ink may represent a new viable route for cost-effective and simple fabrication of very thin silver films.