Three-dimensional theory on light-induced near-field dynamics in a metal film with a periodic array of nanoholes

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Abstract
We present a theoretical study of ultrafast light propagation through a periodic array of nanoapertures in an optically thick metal film. Studying the propagation of 10-fs pulses shorter than the damping time of surface plasmon excitations at the interfaces of the metal film, we find pronounced temporal oscillations in the transmitted light. The oscillations reflect the coupling of surface plasmon polaritons at both interfaces via photon tunneling through the nanohole channel. The diameter of the nanoholes is the main parameter governing the period and damping of these oscillations. Radiation damping of surface plasmon excitations through scattering at the nanoholes is identified as an important damping mechanism. Our results give insight into the physics of light transmission through nanohole gratings and clear guidelines for designing the optical properties of these nanostructures.