Terahertz Fresnel-zone-plate film lens based on double-layer metamaterial phase shifter

Zhengli Han, Yuma Takida, Seigo Ohno, Hiroaki Minamide

Publikation: Bidrag til bog/antologi/rapport/proceedingKonferencebidrag i proceedingsForskningpeer review

1 Citationer (Scopus)

Abstract

We have developed a thin THz-wave planar lens based on the phase-patterned Fresnel zone plate (FZP) concept to obtain a high transmittance and short focal length in free space. The FZP lens was designed for focusing THz waves at 1.0 THz (λ=300 μm) with a transmittance of more than 80% and a focal length of 24 mm (80λ). The developed FZP lens was made of polymer BCB as a flexible film substrate with concentric zones of metamaterial-based phase shifter patterns with a subwavelength thickness of approximately 48 μm (0.16λ). To obtain the THz-wave phase retardation of i€/2 compared to the naked polymer substrate, we employed the metamaterial unit structure consisting of double-layer unsplit ring resonators (USRRs) with a 32-μm distance between the two layers. The experimental result confirms that the FZP lens creates a focus by constructive interference of incident THz waves through concentric zones of metamaterial-patterned and un-patterned regions. By using a narrowband THz-wave beam from an injection-seeded THz-wave parametric generator, the measured focus spot size of 0.57 mm at full width at half maximum was obtained at the designed frequency of 1.0 THz. Using this FZP lens, the THz-wave imaging test in transmission geometry has also been demonstrated.

OriginalsprogEngelsk
TitelTerahertz Photonics
RedaktørerMona Jarrahi, Sascha Preu, Dmitry Turchinovich
ForlagSPIE - International Society for Optical Engineering
Publikationsdato2020
Artikelnummer1134806
ISBN (Elektronisk)9781510634688
DOI
StatusUdgivet - 2020
Udgivet eksterntJa
BegivenhedTerahertz Photonics 2020 - none, Frankrig
Varighed: 6 apr. 202010 apr. 2020

Konference

KonferenceTerahertz Photonics 2020
Land/OmrådeFrankrig
Bynone
Periode06/04/202010/04/2020
NavnProceedings of SPIE - The International Society for Optical Engineering
Vol/bind11348
ISSN0277-786X

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