Voltage-tunable dual-layer terahertz metamaterials

Zhao, Xiaoguang; Fan, Kebin; Zhang, Jingdi; Keiser, George R.; Duan, Guangwu; Averitt, R. D.; Zhang, Xin

doi:10.1038/micronano.2016.25

Cited by 81 publications

(46 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although a number of THz tunable transmission filters based on MEMS-driven metamaterials have been demonstrated [19][20][21][22][23][24][25][26][27][28][29][30][31] , the realization of a high-performance MEMS-driven tunable THz absorber is still challenging, and only a limited number of demonstrations have been reported so far 32 . This low number is primarily due to the severe mismatch between the actuation range of most MEMS (on the scale of 1-10 μm) and THz wavelengths on the scales of 100-1000 μm.…”

Section: Introductionmentioning

confidence: 99%

Ultrathin tunable terahertz absorber based on MEMS-driven metamaterial

et al. 2017

View full text Add to dashboard Cite

The realization of high-performance tunable absorbers for terahertz frequencies is crucial for advancing applications such as single-pixel imaging and spectroscopy. Based on the strong position sensitivity of metamaterials' electromagnetic response, we combine meta-atoms that support strongly localized modes with suspended flat membranes that can be driven electrostatically. This design maximizes the tunability range for small mechanical displacements of the membranes. We employ a micro-electromechanical system technology and successfully fabricate the devices. Our prototype devices are among the best-performing tunable THz absorbers demonstrated to date, with an ultrathin device thickness (~1/50 of the working wavelength), absorption varying between 60% and 80% in the initial state when the membranes remain suspended, and fast switching speed (~27 μs). The absorption is tuned by an applied voltage, with the most marked results achieved when the structure reaches the snap-down state. In this case, the resonance shifts by 4200% of the linewidth (14% of the initial resonance frequency), and the absolute absorption modulation measured at the initial resonance can reach 65%. The demonstrated approach can be further optimized and extended to benefit numerous applications in THz technology.

show abstract

Section: Introductionmentioning

confidence: 99%

Ultrathin tunable terahertz absorber based on MEMS-driven metamaterial

et al. 2017

View full text Add to dashboard Cite

show abstract

“…Various methods to make a relative displacement between closely placed pair of meta-atoms or pair of metasurfaces have been reported. [13][14][15][16][17][18][19][20][21][22][23][24] When two (or more) meta-atoms are placed close enough to couple via near-field interactions, new resonant modes can be supported akin to bonding and antibonding molecular orbitals in molecular systems. These new resonant modes are quite sensitive to the relative position and/or orientation of meta-atoms and therefore can give a mechanism to tune the resonant frequency by giving a relative displacement.…”

Section: Introductionmentioning

confidence: 99%

“…Similar mechanisms can apply to layered arrays of meta-atoms or metasurfaces. Recently, such active tuning has been experimentally realized by slightly shifting relative position of double-layered metamaterials utilizing π-conjugated polymer actuators, 22 MEMS actuators, 23 or microcantilever. 24 We recently demonstrated that double-layered closed-ring resonator (CRR) arrays are capable of relatively large tuning.…”

Section: Introductionmentioning

confidence: 99%

Index-tunable terahertz metamaterials based on double-layered closed-ring resonator arrays

Watanabe

Matsui

2018

J. Photon. Energy

View full text Add to dashboard Cite

, "Index-tunable terahertz metamaterials based on double-layered closed-ring resonator arrays," J. Photon. Energy 8(3), 032211 (2018), doi: 10.1117/1.JPE.8.032211. Abstract. We demonstrate index-tunable metamaterials working in the terahertz (THz) frequency range based on double-layered closed-ring resonator (CRR) arrays. The double-layered CRR arrays have a narrow-band transmission peak in a relatively wide stop band, and that peak shows spectral shift by slightly shifting relative position of the arrays or changing dielectric constant of the dielectric media inserted between CRR arrays. We show by numerical simulations that the effective refractive index can be widely tuned from un-naturally high positive to near-zero and negative values. Our approach may be utilized to develop THz active devices.

show abstract

“…Recently, the design and fabrication of planar THz metamaterials and modulators based on them have been discussed intensively. Ref [16][17][18][19][20][21][22][23][24] suggested us the possibilities for successful implementation of proposed metamaterials in future.…”

mentioning

confidence: 99%

“…The metamaterials with incorporated silicon or gallium arsenide inclusions were discussed in details as elements of modulators. The phase tunability, blueshift, redshift as well as amplitude switching shown in THz frequency range [16][17][18][19][20][21][22][23][24]. Although the semiconductor inclusions play the role of capacitor elements or as the tunable metamaterial substrate.…”

mentioning

confidence: 99%

Blueshift and phase tunability in planar THz metamaterials: the role of losses and toroidal dipole contribution

2017

View full text Add to dashboard Cite

We propose a model of tunable THz metamaterials. The main advantage is the blueshift of resonance and phase tunability due to toroidal excitation in planar metallic metamolecules with incorporated silicon inductive inclusions.Metamaterials are artificial structures with properties unattainable in natural media. Their exotic response is a promising platform for filling the THz frequency gap [1][2][3]. A separate class of metamaterials is the one with the toroidal response [4][5][6][7][8][9][10][11][12][13][14][15]. The toroidal observation is mediated by the excitation of currents flowing in inclusions of toroidal metamolecules, and resembles the poloidal currents along the meridians of gedanken torus [4,5]. Meanwhile, the destructive interference between the toroidal and electric dipole moments leads to lack the far-fields, but the fields in the metamolecule origin describing by δ-function [6,7]. Such fields configuration, referred as the anapole, allows to observe the new effect of Electromagnetically Induced Transparency (EIT) [6,7], provides an extremely high Q-factor in metamaterials [8], enables a cloaking for nanoparticles [9,10], and is a platform for confirmation of the dynamic Aharonov-Bohm effect [6,7]. Recently, it was demonstrated the anapole excitation in planar metamaterials, which enabled an extremely high Q-factor in microwave [8], which gives promising opportunities for tunable metamaterials due to the strong electromagnetic fields localization within metamolecules. In this paper, we consider a design of a metamaterial, discussed in Ref. 8, in tunable regime. For this purpose, we incorporate the photoconductive silicon into the metamolecule (Fig. 1a) and study the response of the metamaterial in the THz regime. The silicon is simulated with the permittivity εSi=11.7 and a pumppower-dependent conductivity σSi, varied from 10 -1 up to 10 6 S/m, which means transition from dielectric to metallic state. Metamolecules comprise of two split parts (Fig. 1a). The incident plane electromagnetic wave with electric field E aligned with the central wire excites conductive currents in each loop of the metamolecule. The currents form a closed vortex of magnetic field H. As a result, such configuration of electromagnetic fields supports the toroidal dipole excitation, oscillating upward and downward within metamolecule. However, the electric dipole also arises in the metamolecule and maintains the anapole mode, in accordance with the destructive interference between electric and toroidal dipole moments. The advantage is a very narrow line in the transmission spectrum of a metamaterial [8]. Here, for the first time, we consider how the planar toroidal metamolecule can be exploited as a building block for terahertz modulators. We demonstrate the blueshift and the phase tunability regime and also discuss the role of losses. The metamaterials with incorporated silicon or gallium arsenide inclusions were discussed in details as elements of modulators. The phase tunability, blueshift, redshift as well as amplitude ...

show abstract

Voltage-tunable dual-layer terahertz metamaterials

Cited by 81 publications

References 44 publications

Ultrathin tunable terahertz absorber based on MEMS-driven metamaterial

Ultrathin tunable terahertz absorber based on MEMS-driven metamaterial

Index-tunable terahertz metamaterials based on double-layered closed-ring resonator arrays

Blueshift and phase tunability in planar THz metamaterials: the role of losses and toroidal dipole contribution

Contact Info

Product

Resources

About