Far-Field and Near-Field Physics of Extraordinary THz Transmitting Hole-Array Antennas

Miguel Camacho,Miguel Beruete,Sergei A Kuznetsov,Rafael R Boix,Miguel Navarro-Cia

doi:10.1109/tap.2019.2920262

Abstract

Despite three decades of effort, predicting accurately extraordinary transmission through subwavelength hole arrays has proven challenging. The lack of quantitative design and modeling capability to take into account the inherent complexity of high frequency instrumentation has prevented the development of practical high-performance components based on this phenomenon. This paper resorts to the Method of Moments to provide not only such missing quantitative prediction but also a theoretical framework to understand and shed more light on the far-field and near-field physics of the extraordinary terahertz (THz) transmission through subwavelength hole arrays under different illumination and detection conditions. An excellent agreement between the numerical and experimental results with various illumination and detection setups is obtained, demonstrating the suitability of this computationally efficient modeling tool to predict the response of extraordinary transmission structures in practical situations.

Highlights

T HE discovery of extraordinary optical transmission (EOT) in the late 1990s [1]–[3] stimulated the research on a type of frequency selective surfaces that had been little studied until
A few years later, this finding was explained in terms of the coupling of the incident wave to surface plasmon polaritons supported by the metal–air interface [5]
As shown in [17], the electric field distribution of subwavelength hole arrays operating at the EOT frequency changes sharply when they are excited with a localized source, a fact that is not observed in the theoretical works that use a plane wave illumination or in the experimental works done in the far-field range

Summary

Introduction

T HE discovery of extraordinary optical transmission (EOT) in the late 1990s [1]–[3] stimulated the research on a type of frequency selective surfaces that had been little studied until . Thanks to periodicity, subwavelength hole arrays present a very narrow passband at frequencies slightly below the first onset of diffraction. This feature attracted much attention for its promising filtering and sensing applications at optical frequencies [4]. A few years later, this finding was explained in terms of the coupling of the incident wave to surface plasmon polaritons supported by the metal–air interface [5] This phenomenon was later found at microwave frequencies [6], where the role of the surface plasmons was taken by leaky waves, supported by the hole array [7]. As shown in [17], the electric field distribution of subwavelength hole arrays operating at the EOT frequency changes sharply when they are excited with a localized source, a fact that is not observed in the theoretical works that use a plane wave illumination or in the experimental works done in the far-field range

Methods

Results

Conclusion