Abstract: Using atomically smooth epitaxial silver films, new optical permittivity highlighting significant loss reduction in the visible frequency range is extracted. Largely enhanced propagation distances of surface plasmon polaritons are measured, confirming the low intrinsic loss in silver. The new permittivity is free of extrinsic spectral features associated with grain boundaries and localized plasmons inevitably present in thermally deposited films.
Y. Wu, C. Zhang, N. M. Estakhri, Y. Zhao, J. Kim, M. Zhang, X. X. Liu, G. K. Pribil, A. Alù, C. K. Shih, X. Li. Intrinsic optical properties and enhanced plasmonic response of epitaxial silver, Adv. Mater.26, 6106-6110 (2014) (See Supporting information)
Silver (Ag) is a highly reflective metal known for its excellent electrical and thermal conductivity, making it a material of interest in a variety of optical and electronic applications. In the realm of optics, silver is frequently used as a coating material for mirrors due to its high reflectivity across a broad range of wavelengths, from ultraviolet to infrared. Additionally, silver nanoparticles are employed in plasmonic devices, enhancing light-matter interactions at the nanoscale. While the metal is highly stable under most conditions, it is susceptible to tarnishing in the presence of sulfur compounds, which can diminish its optical performance over time. Silver's unique combination of properties, including its unparalleled reflectivity and high electrical conductivity, makes it a versatile material in the field of optics and photonics. Note that its refractive index can vary depending on the form in which it is used, such as bulk silver, thin films, or nanoparticles, making it crucial to consult specific data for particular applications.