Spectral control of near-field radiation transfer by interference of Surface Plasmon Polariton in pillar array structured conductors

Abstract

Spectral control of near-field radiation transfer by interference of Surface Plasmon Polaritons (SPPs) in pillar array structured surface made of nickel was investigated using a numerical simulation based on Maxwell’s electromagnetic wave theory. The electromagnetic field between two pillar array structured surfaces fixed in face to face with a vacuum gap of several hundred nanometers was obtained using a three dimensional Finite Difference Time Domain (FDTD) method and fluctuational electrodynamics (FED). The near-field radiation flux from a high temperature to a low temperature pillar array structured surfaces was evaluated through the summation of normal components of Poynting vector in any direction at the intermediate of the vacuum gap. Through the numerical simulation, it was clarified that the local maximum and the local minimum of near-field radiation flux were shown periodically with increasing height of pillar under the condition of a fixed vacuum gap, which was regarded as interference between the pillar height and an electromagnetic wave propagating in the channel between pillars. Moreover, the dispersion relation of the electromagnetic wave with interference in the channel between pillars is quite similar to the SPPs established in two semi-infinite smooth plates with a nanometer vacuum gap. As a result, it was concluded that the spectral control of near-field radiation transfer was achieved by interference of SPPs in the channel between pillars by tuning the height of pillar.