Terahertz characterization of two-dimensional low-conductive layers enabled by metal gratings

Gopalan, Prashanth; Wang, Yunshan; Sensale‐Rodriguez, Berardi

doi:10.1038/s41598-021-82560-2

Cited by 6 publications

(1 citation statement)

References 44 publications

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“…As was seen, the peak transmission increased with the h Au while it was maintained for h Au ≥ 100 nm. It is because that the transmission spectrum of the EOT metamaterials was independent of the Au film thickness when it is larger than the skin depth in the Au 49,50 . Thus, herein the diameter and height of the Au holes were determined at d =60 μm and h Au = 200 nm.…”

Section: Resultsmentioning

confidence: 99%

Multi-cycle reconfigurable THz extraordinary optical transmission using chalcogenide metamaterials

Cao¹,

Lian²,

Chen³

et al. 2021

OES

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Metamaterials composed of metallic antennae arrays are used as they possess extraordinary optical transmission (EOT) in the terahertz (THz) region, whereby a giant forward light propagation can be created using constructive interference of tunneling surface plasmonic waves. However, numerous applications of THz meta-devices demand an active manipulation of the THz beam in free space. Although some studies have been carried out to control the EOT for the THz region, few of these are based upon electrical modulation of the EOT phenomenon, and novel strategies are required for actively and dynamically reconfigurable EOT meta-devices. In this work, we experimentally present that the EOT resonance can be coupled to optically reconfigurable chalcogenide metamaterials which offers a reversible all-optical control of the THz light. A modulation efficiency of 88% in transmission at 0.85 THz is experimentally observed using the EOT metamaterials, which is composed of a gold (Au) circular aperture array sitting on a non-volatile chalcogenide phase change material (Ge 2 Sb 2 Te 5 ) film. This comes up with a robust and ultrafast reconfigurable EOT over 20 times of switching, excited by a nanosecond pulsed laser. The measured data have a good agreement with finite-element-method numerical simulation. This work promises THz modulators with significant on/off ratios and fast speeds.

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Section: Resultsmentioning

confidence: 99%

Multi-cycle reconfigurable THz extraordinary optical transmission using chalcogenide metamaterials

Cao¹,

Lian²,

Chen³

et al. 2021

OES

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Real-time detection of aging status of methylammonium lead iodide perovskite thin films by using terahertz time-domain spectroscopy

Xu,

Wu,

Fan

et al. 2024

Front. Optoelectron.

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The inadequate stability of organic–inorganic hybrid perovskites remains a significant barrier to their widespread commercial application in optoelectronic devices. Aging phenomena profoundly affect the optoelectronic performance of perovskite-based devices. In addition to enhancing perovskite stability, the real-time detection of aging status, aimed at monitoring the aging progression, holds paramount importance for both fundamental research and the commercialization of organic–inorganic hybrid perovskites. In this study, the aging status of perovskite was real-time investigated by using terahertz time-domain spectroscopy. Our analysis consistently revealed a gradual decline in the intensity of the absorption peak at 0.968 THz with increasing perovskite aging. Furthermore, a systematic discussion was conducted on the variations in intensity and position of the terahertz absorption peaks as the perovskite aged. These findings facilitate the real-time assessment of perovskite aging, providing a promising method to expedite the commercialization of perovskite-based optoelectronic devices. Graphical Abstract

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On the terahertz response of metal-gratings on anisotropic dielectric substrates and its prospective application for anisotropic refractive index characterization

Jia

Gopalan

Bhattacharyya

et al. 2022

Journal of Applied Physics

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This paper discusses the terahertz electromagnetic response of metallic gratings on anisotropic dielectric substrates. The metallic gratings consist of parallel gold stripes. Utilizing numerical simulations, we observe that it is possible to excite a series of resonant modes in these structures. These modes are affected differently by the different indices on the anisotropic substrate. An analytical model is discussed to show that modes associated with transmission peaks are due to the excitation of (a) Fabry–Pérot modes with polarization along the grating and/or (b) waveguide modes with polarization perpendicular to the grating. It is observed that the resonance associated with the TM1,1 mode is a narrow linewidth resonance which, in some particular circumstances, becomes nearly independent of substrate thickness. Therefore, from the spectral position of this resonance, it is possible to extract the out-of-plane component of the substrate refractive index with very small uncertainty. Based on this observation, we demonstrate the refractive index characterization of several lossless semiconductor substrates through frequency-domain polarized terahertz transmission measurements in the frequency range of 0.2–0.6 THz at normal incidence. The reliability of the technique is demonstrated on well-known materials, such as high-resistivity silicon and sapphire substrates. This technique is also applied for the characterization of a Fe-doped β-Ga2O3 single-crystal substrate.

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Terahertz characterization of two-dimensional low-conductive layers enabled by metal gratings

Cited by 6 publications

References 44 publications

Multi-cycle reconfigurable THz extraordinary optical transmission using chalcogenide metamaterials

Multi-cycle reconfigurable THz extraordinary optical transmission using chalcogenide metamaterials

Real-time detection of aging status of methylammonium lead iodide perovskite thin films by using terahertz time-domain spectroscopy

On the terahertz response of metal-gratings on anisotropic dielectric substrates and its prospective application for anisotropic refractive index characterization

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