Thermally induced tunability of a terahertz metamaterial by using a specially designed nematic liquid crystal mixture

Kowerdziej, Rafał; Olifierczuk, Marek; Parka, Janusz

doi:10.1364/oe.26.002443

Cited by 31 publications

(19 citation statements)

References 39 publications

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“…This results in greater light scattering. Therefore, a red-shift and a widening of the resonance curve is observed 15,24 . Nevertheless, the experimental results clearly show that the metadevice can be tuned effectively, with an intensity change of up to 5.5% and spectrum up to 100 nm, just by changing the magnitude of the AC bias voltage, as evident from Fig.…”

Section: Resultsmentioning

confidence: 94%

Ultrafast electrical switching of nanostructured metadevice with dual-frequency liquid crystal

Kowerdziej

Wróbel

Kula

2019

Sci Rep

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Shortening of switching times of various soft-matter-based tunable metamaterials is one of the key challenges to improve the functionality of modern active devices. Here we show an effective strategy in the evolution of soft-matter-based tunable metamaterials that makes possible acceleration of both on and off switching processes by using a dual-frequency liquid crystal mixture. The frequency-convertible dielectric anisotropy of the dual-frequency mixture enabled us to create a fast-response in-plane switching metasurface at the nanoscale, which could be tuned by an electrical signal with different frequencies. The results clearly show that the resonance of the metamaterial can be continuously and reversibly controlled within a wavelength range of 100 nm as the applied frequency is inverted between 1 kHz and 40 kHz, with a total response time (τ = τON + τOFF) of 1.89 ms. Furthermore, experimental characteristics of the hybrid metamaterial are in great agreement with numerical calculations, which allow us to anticipate active epsilon-near-zero behavior of the metadevice. This work indicates the future development direction of liquid-crystal-based active plasmonic systems.

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Section: Resultsmentioning

confidence: 94%

Ultrafast electrical switching of nanostructured metadevice with dual-frequency liquid crystal

Kowerdziej

Wróbel

Kula

2019

Sci Rep

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“…One can also realize thermally induced tunability in terahertz metamaterials-based devices, e.g. by using a specially designed nematic liquid crystal mixture [49]. In this work we focus on achieving tuneable optical properties mainly in the visible spectral range.…”

Section: Resultsmentioning

confidence: 99%

Optical response of electro-tuneable 3D superstructures of plasmonic nanoparticles self-assembling on transparent columnar electrodes

Sikdar¹,

Weir²,

Kornyshev³

2019

Opt. Express

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Electrically tuneable, guided self-assembly of plasmonic nanoparticles (NPs) at polarized, patterned solid-liquid interfaces could enable numerous platforms for designing nanoplasmonic optical devices with new tuneable functionalities. Here, we propose a unique design of voltage-controlled guided 3D self-assembly of plasmonic NPs on transparent electrodes, patterned as columnar structures-arrays of vertical nanorods. NP assembly on the electrified surfaces of those columnar structures allows formation of a 3D superstructure of NPs, comprising stacking up of NPs in the voids between the columns, forming multiple NP-layers. A comprehensive theoretical model, based on quasi-static effective medium theory and multilayer Fresnel reflection scheme, is developed and verified against full-wave simulations for obtaining optical responses-reflectance, transmittance, and absorbance-from such systems of 3D self-assembled NPs. With a specific example of small gold nanospheres self-assembling on polarized zinc oxide columns, we show that the reflectance spectrum can be controlled by the number of stacked NP-layers. Numerical simulations show that peak reflectance can be enhanced up to ∼1.7 times, along with spectral broadening by a factor of ∼2-allowing wide-range tuning of optical reflectivity. Smaller NPs with superior mobility would be preferable over large NPs for realizing such devices for novel photonic and sensing applications.

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“…The refractive index of liquid crystals is also temperature adjustable. In 2018, Kowerdziej demonstrated the tunability of thermally induced liquid crystal metamaterials [151], as shown in Figure 13d. The thermal tunability of this metamaterial device is attributed to the temperature sensitivity of the liquid crystal dielectric constant contained in the metamaterial cavity.…”

Section: Liquid Crystal Metasurfacementioning

confidence: 99%

“…( d ) Schematic diagram and resulting temperature control structure combining the liquid crystal and metamaterial transmission modulator. Reproduced with permission from [151]. ( e ) Electrically controlled phase shifter composed of the liquid crystal and metasurface can obtain phase shifting with varying electric field power.…”

Section: Figurementioning

confidence: 99%

A Review of THz Modulators with Dynamic Tunable Metasurfaces

et al. 2019

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Terahertz (THz) radiation has received much attention during the past few decades for its potential applications in various fields, such as spectroscopy, imaging, and wireless communications. To use terahertz waves for data transmission in different application systems, the efficient and rapid modulation of terahertz waves is required and has become an in-depth research topic. Since the turn of the century, research on metasurfaces has rapidly developed, and the scope of novel functions and operating frequency ranges has been substantially expanded, especially in the terahertz range. The combination of metasurfaces and semiconductors has facilitated both new opportunities for the development of dynamic THz functional devices and significant achievements in THz modulators. This paper provides an overview of THz modulators based on different kinds of dynamic tunable metasurfaces combined with semiconductors, two-dimensional electron gas heterostructures, superconductors, phase-transition materials, graphene, and other 2D material. Based on the overview, a brief discussion with perspectives will be presented. We hope that this review will help more researchers learn about the recent developments and challenges of THz modulators and contribute to this field.

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Thermally induced tunability of a terahertz metamaterial by using a specially designed nematic liquid crystal mixture

Cited by 31 publications

References 39 publications

Ultrafast electrical switching of nanostructured metadevice with dual-frequency liquid crystal

Ultrafast electrical switching of nanostructured metadevice with dual-frequency liquid crystal

Optical response of electro-tuneable 3D superstructures of plasmonic nanoparticles self-assembling on transparent columnar electrodes

A Review of THz Modulators with Dynamic Tunable Metasurfaces

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