Ultra-wideband tri-layer transmissive linear polarization converter for terahertz waves

Rajour Tanyi Ako,Madhu Bhaskaran,Wendy S L Lee,Sharath Sriram,Withawat Withayachumnankul,Shaghik Atakaramians

doi:10.1063/1.5144115

Rajour Tanyi Ako, Madhu Bhaskaran + Show 4 more

Open Access

https://doi.org/10.1063/1.5144115

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Abstract

Polarization control is shown to enhance functionalities of terahertz waves in various applications. As a step toward introducing efficient practical devices operating in the terahertz band, we propose and experimentally validate a free-standing three-layer polarization converter operating in transmission. The device can efficiently convert a linearly polarized terahertz wave to its orthogonal counterpart. Our device comprises split-ring and H-shaped resonators inserted between two layers of orthogonal wire gratings. The sole dielectric material is a cyclic olefin copolymer (COC) that has exceptionally low-loss to terahertz waves. The measurement demonstrates a conversion efficiency of >80%, over 0.2–1.0 THz, giving an ultra-wide bandwidth of 133%. The wide bandwidth is attributed to multiple resonances of the two resonators in a unit cell. Importantly, an unconventional fabrication process yields a multi-layer low-loss COC that leads to high efficiency. The proposed design can also be tailored for practical applications across the electromagnetic spectrum.

Highlights

Polarization control is one of the main mechanisms facilitating applications such as high contrast imaging,1,2 screening of optically active molecules,3 or reducing a radar cross section.4 A wide range of polarization conversion techniques, such as linearto-linear,4–11 linear-to-circular,9,12,13 left handed circular-to-right handed circular,14 or its preservation,9 have been demonstrated in the technology-rich terahertz frequency region
As a step toward introducing efficient practical devices operating in the terahertz band, we propose and experimentally validate a free-standing three-layer polarization converter operating in transmission
The sole dielectric material is a cyclic olefin copolymer (COC) that has exceptionally low-loss to terahertz waves

Summary

Introduction

Polarization control is one of the main mechanisms facilitating applications such as high contrast imaging,1,2 screening of optically active molecules,3 or reducing a radar cross section.4 A wide range of polarization conversion techniques, such as linearto-linear,4–11 linear-to-circular,9,12,13 left handed circular-to-right handed circular,14 or its preservation,9 have been demonstrated in the technology-rich terahertz frequency region. As a step toward introducing efficient practical devices operating in the terahertz band, we propose and experimentally validate a free-standing three-layer polarization converter operating in transmission.

Results

Conclusion