A micromachined freestanding terahertz absorber with an array of metallic patches

Hamdi Torun,Arda D Yalcinkaya,Seyedehayda Sadeghzadeh,Habib Bilgin

doi:10.1063/1.4945417

Abstract

An array of square metallic patches on a thin suspended dielectric layer is introduced as an effective terahertz absorber. The suspended structure is placed on a metalized substrate and the device exhibits metamaterial behavior at specific frequencies determined by the size of the patches. It is feasible to place patches with different sizes in an array formation for a broadband absorber. In array configuration, individual elements induce distinct resonances yielding narrow band absorption regions. Design of the absorber is described using electromagnetic simulations. The absorber structure was fabricated on a silicon wafer using standard microfabrication techniques. The characteristics of the absorber were measured using a terahertz time domain spectroscope. The measured data match well the simulations indicating strong absorption peaks in a band of 0.5-2 THz.

Highlights

Metamaterials are patterned sub-wavelength sized structures that are usually made of dielectrics and metals
An array of square metallic patches on a thin suspended dielectric layer is introduced as an effective terahertz absorber
They exhibit strong resonant behavior when they are excited with electromagnetic waves and the resonant frequencies are determined by the geometries of the patterned structures

Summary

INTRODUCTION

Metamaterials are patterned sub-wavelength sized structures that are usually made of dielectrics and metals. They exhibit strong resonant behavior when they are excited with electromagnetic waves and the resonant frequencies are determined by the geometries of the patterned structures. We present a metamaterial-based terahertz absorber employing metallic square patches implemented in the same plane with different sizes. Metallic patches with different sizes are laid out on a single Parylene film that is anchored to the substrate through a set of suspensions. This configuration is desirable for terahertz detectors that requires pixel structures isolated from their substrate. The thickness of the air gap between the Parylene layer and the blanket metal is 5 μm

SIMULATIONS AND MODELING

Findings

CONCLUSION