Structured continuous thick metal film with largely enhanced transmission

Using the discrete dipole approximation (DDA) method, we propose a sandwiched nano-film system that consists of a continuous metal film and two two-dimensional (2D) nanoparticle arrays separated by two layers of glass substrates. Varying the thickness of the glass substrate layers, the localized and propagating surface plasmon polaritions (SPPs) can interact constructively to enhance the transmission of the continuous metal film. The transmission efficiency can be as high as 80% for a continuous silver film with a thickness of 50 nm, which is a 16-fold increase in comparison to that of an isolated metal film only. The FWHM of the transmission peak can also be controlled through changing the interparticle distances and other parameters of the nanoparticles. The significantly enhanced transmission provides us a new approach for the study the optical properties of a continuous metal film and the design of novel devices with enhanced transmission based on nanostructures.