ACS Photon. http://doi.org/2q7(2015)

Although the use of high-quality metal films will not solve the loss issue for plasmonics, it can be a substantial improvement if the metal is deposited in a certain way. Kevin McPeak and colleagues at ETH Zurich, Switzerland, have created a cookbook for reproducibly making high-quality Ag, Au, Cu and Al metal films for plasmonics with optical performance that is much better than standard references. They focused on the commonly available thermal evaporation technique so that the majority of researchers can benefit from their work. McPeak et al. detailed every step of the process, determined the optimal deposition conditions and measured optical performance. They reveal a real part of the permittivity that is similar to standard references but with imaginary (loss-related) parts that are significantly smaller. Quality factors for localized resonance and standard propagation on Ag are improved by 200% and 250%, respectively, at a wavelength of 650 nm. The team highlights that fast deposition is often advantageous for achieving larger grain sizes as it gives less time for reaction with residual gases in the chamber. Larger grain means less scattering due to less boundaries.