Design of a tunable terahertz narrowband metamaterial absorber based on an electrostatically actuated MEMS cantilever and split ring resonator array

Hu, Fangrong; Qian, Yixian; Li, Zhi; Niu, Junhao; Nie, Kun; Xiong, Xiang; Zhang, Wentao; Peng, Zhiyong

doi:10.1088/2040-8978/15/5/055101

Cited by 70 publications

(35 citation statements)

References 27 publications

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“…We combine meta-atoms that support strongly localized modes with flat, suspended silicon nitride membranes that can be driven electrostatically. Unlike tunable absorbers based on tilted cantilevers 32,41 , flat membranes can maximize the coupling between meta-atoms and the ground plane and enhance the modulation contrast by avoiding resonance broadening due to tilting. Our prototype devices show very good performance: strong absorption (60-80% at the initial state when the membranes remain suspended), fast switching speed (switching time ∼27 μs), highly enhanced mechanical sensitivity (δλ 0 /δd can be up to 14.8 when the device is driven to snap-down), and large modulation contrast (up to 65% of absolute change in absorption at the initial resonance under the snap-down state).…”

Section: Introductionmentioning

confidence: 99%

Ultrathin tunable terahertz absorber based on MEMS-driven metamaterial

et al. 2017

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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.

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Section: Introductionmentioning

confidence: 99%

Ultrathin tunable terahertz absorber based on MEMS-driven metamaterial

et al. 2017

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“…To date there have been several demonstrations of MEMS techniques utilized to achieve tunable response at THz and lower frequencies and near infrared wavelengths as well as for constructing diffractive gratings . In our study, the metamaterial unit cell (shown in Figure ) consists of four layers above a carrier substrate.…”

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confidence: 99%

Dynamic Manipulation of Infrared Radiation with MEMS Metamaterials

Liu

Padilla

2013

Advanced Optical Materials

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559 wileyonlinelibrary.com COMMUNICATION www.MaterialsViews.com www.advopticalmat.deThe advent of metamaterials has ushered in a new era of designer electromagnetic materials and has realized novel responses ranging from negative refractive index [1][2][3][4] and superlensing [ 7 ] to perfect absorption [ 8,9 ] and cloaking. [ 5,6 ] Metamaterials are fashioned from 'artifi cial atoms', which are engineered to yield a specifi c response to the electric and magnetic components of light, the properties of which are preserved in a macroscopic medium fabricated from their individual units. Electromagnetic properties achieved by metamaterials derive from the geometry of their unit cells, as opposed to the bandstructure of their makeup. Metamaterials are thus a bottom-up design paradigm for the construction of advanced materials and hold great potential for applications spanning the electromagnetic spectrum. Although metamaterial have realized novel electromagnetic properties, some which have been diffi cult to achieve with natural materials, the ability to dynamically control these responses in real-time would offer signifi cant advantages enabling metamaterials to transition into state-of-the-art devices.Indeed in the past several years, tunable metamaterials have become an important development permitting real time tuning of various electromagnetic responses. Although much work has been carried out in the THz regime, [11][12][13][14][15][16][17] and lower frequencies, [18][19][20] there has been limited success in the infrared range. [ 21 ] Photoexcitation or electrical depletion of extrinsic carriers in semiconductor substrates has been proven to be an effective way for achieving tunability at THz but is extremely diffi cult to achieve at shorter infrared wavelengths, which requires much higher doping densities thus leading to high currents and fi elds which tend to severely limit device lifetimes. Temperature controlled tunable metamaterial responses have been demonstrated in many frequency regimes; [ 15,16,21,22 ] however the long response time prevents their practical use. Ferroelectric materials have been used to experimentally show tuning only at microwave frequencies, [ 18 ] while liquid crystals [ 23,24 ] may be implemented across many frequency bands.Although metamaterials have demonstrated tuning by modifi cation of substrate properties a viable alternative is to change the distance between the metamaterial elements, or the substrate, thereby altering the optimized resonant response and/ or the local dielectric environment, thus providing tunability. Thus by fabricating metamaterials as microelectromechanical systems (MEMS) we may achieve mechanically actuated tuning. [25][26][27] In this communication we experimentally realize an electrically tunable MEMS metamaterial that effectively manipulates radiation in the mid-infrared wavelength range. The metamaterial consists of an array of suspended metaldielectric elements above a metal ground plane on a carrier substrate. A voltage applied between the metallic...

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“…One possible way to achieve frequency tunability of MA is to reconstruct the geometries, but it cannot be applied in the case of dynamic tuning. A tunable MA based on electrostatically actuated MEMS cantilever 11 or varactor loaded resonator 12 has been proposed. However, the fabrication of such structures is complicated.…”

Section: Introductionmentioning

confidence: 99%

Electrically tunable terahertz dual-band metamaterial absorber based on a liquid crystal

Yin

Xia

et al. 2018

RSC Adv.

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In this paper, a liquid crystal (LC) based tunable metamaterial absorber with dual-band absorption is presented. The proposed absorber is analysed both numerically and experimentally. The analysis shows that the two absorption peaks, originating from the new resonant structure, are experimentally detected at 269.8 GHz and 301.4 GHz when no bias voltage is applied to the LC layer. In order to understand the absorption mechanisms, simulation results for the surface current and power loss distributions are presented. Since liquid crystals are used as the dielectric layer to realize the electrically tunable absorber, a frequency tunability of 2.45% and 3.65% for the two absorption peaks is experimentally demonstrated by changing the bias voltage of the LC layer from 0 V to 12 V. Furthermore, the absorber is polarization independent and a high absorption for a wide range of oblique incidence is achieved. The designed absorber provides a way forward for the realization of tunable metamaterial devices that can be applied in multi-band detection and imaging.

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Design of a tunable terahertz narrowband metamaterial absorber based on an electrostatically actuated MEMS cantilever and split ring resonator array

Cited by 70 publications

References 27 publications

Ultrathin tunable terahertz absorber based on MEMS-driven metamaterial

Ultrathin tunable terahertz absorber based on MEMS-driven metamaterial

Dynamic Manipulation of Infrared Radiation with MEMS Metamaterials

Electrically tunable terahertz dual-band metamaterial absorber based on a liquid crystal

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