Probing the Near-Field Inductive Coupling in Broadside Coupled Terahertz Metamaterials

Rao, S. Jagan Mohan; Kumar, Deepak; Kumar, Gagan; Chowdhury, Dibakar Roy

doi:10.1109/jstqe.2016.2635020

Cited by 23 publications

(4 citation statements)

References 46 publications

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“…The radiation intensity characteristics due to Mie multipoles, which are obtained by solving Eqs. ( 2)- (10), as in Fig. 7c,d, also confirm a strong MTQ response at both α = 0° and 45°.…”

Section: Structuresupporting

confidence: 72%

“…Terahertz frequency range has received much attention in recent years for wideband absorber, antennas, wireless communications, magnetic wire, surface plasmons, tunable double plasmon-induced transparency, graphene based devices and sensing applications such as biomedical sensors, chemical detectors, gas sensing and so on [1][2][3][4][5][6][7][8][9][10][11][12][13] . The primary advantage of employing this frequency range for sensor applications is the low photon energy and effective interaction with biomolecules 14 .…”

mentioning

confidence: 99%

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Refractive index sensor based on fano-magnetic toroidal quadrupole resonance enabled by bound state in the continuum in all-dielectric metasurface

Maleki,

Fathi

2024

Sci Rep

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For the first time, an all-dielectric metasurface ultra-sensitive refractive index (RI) sensor with very high quality factor (QF) and figure of merit (FOM), with Fano-magnetic toroidal quadrupole (MTQ) resonance enabled by bound state in continuum (BIC) in terahertz (THz) region was designed. Furthermore, the MTQ resonance in the THz due to a distortion of symmetry-protected bound states in the continuum in the designed structure was investigated. Also, to achieve the dark mode, a combination of three methods including (i) breaking the symmetry, (ii) design of complex structures, and (iii) changing the incident angle was utilized. The broken symmetry in the structure caused a new mode to be excited, which is suitable for sensing applications. The designed metasurface was able to sense a wide range of RI in MTQ resonance, where its properties were improved for the value of sensitivity (S) from 217 GHz/RIU to 625 GHz/RIU, for FOM from 197 RIU–1 to 2.21 × 106 RIU–1 and for QF from 872 to 5.7 × 106.

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Section: Structuresupporting

confidence: 72%

mentioning

confidence: 99%

Refractive index sensor based on fano-magnetic toroidal quadrupole resonance enabled by bound state in the continuum in all-dielectric metasurface

Maleki,

Fathi

2024

Sci Rep

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“…Although, most of the structures are limited to low surface area for strong light matter interaction (for example, split ring resonators possess high confinement of electromagnetic field inside the split gap region only, whose area is very small compared to total device area). Moreover, such structures do not have the ability for broadside coupling, which can lead to much higher energy confinement potential among different near-field coupling schemes [37][38][39][40][41][42]. Recently, Fano resonance has been excited in geometrically symmetric metasurfaces [42], which have the unique ability to confine light in deep sub-wavelength near-field coupling regime.…”

Section: Introductionmentioning

confidence: 99%

Strong terahertz matter interaction induced ultrasensitive sensing in Fano cavity based stacked metamaterials

Karmakar¹,

Kumar²,

Varshney³

et al. 2020

J. Phys. D: Appl. Phys.

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Strong interaction between terahertz (THz) and matter is a topic of paramount importance, considering continuously enhanced interest in THz photonics as well as condensed matter physics, which can lead to the observation of many linear and nonlinear phenomena in the THz regime. Here, we demonstrate a unique and novel metamaterial-based technique of strong THz matter interaction towards thin film sensing, where the analyte is sensed in between the stacked metasurfaces forming the Fano cavity. Sub-wavelength structures typically overcome the diffraction limit of any optical system, which also possess very high confinement of electromagnetic energy. Fano resonance possesses a sharp asymmetric line shape, low radiation loss and large tuning capability. In addition to them, the material under test is placed in between the metasurfaces to utilize the substantial energy confinement leading to strong light matter interaction, a scheme never explored before. By intelligently exploiting the above characteristics, we have demonstrated a novel way to detect both the refractive index (dielectric constant), thickness and loss factor of the material under test when placed between the array of the meta-resonators forming the Fano metamaterials. Our study revealed that the sensitivity and figure of merit (FOM) are strikingly different for dipole and Fano modes. A maximum sensitivity of >1 THz RIU −1 (1.76 × 10 5 nm RIU −1 ) and FOM of around 14.05 are achieved at the Fano mode. Additionally, our sensor shows better performance with decreasing spacer thickness (lesser the material, more the sensitivity). Moreover, the proposed device is passive towards typical ambience temperature variation, and is highly compact because of its stacked configuration. The demonstrated device can be extremely beneficial towards realizing ultra-sensitive meta-sensors and other miniaturized THz meta-photonic devices, and bio-chemical sensing where strong light matter interaction is mandatory.

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“…Fundamentally Metamaterial (MM) is an arrangement of artificial structured elements designed to achieve unusual but desired electromagnetic (EM) properties 27 – 33 . Typically, split ring resonators (SRRs) are the basic building blocks of metamaterials with lattice constant much smaller than the excitation wavelengths 34 – 39 . In recent times, a lot of emphasis has been given to the fabrication of terahertz metamaterials and realization of terahertz photonic devices.…”

Section: Introductionmentioning

confidence: 99%

Modulating Fundamental Resonance in Capacitive Coupled Asymmetric Terahertz Metamaterials

Rao

Srivastava

Kumar

et al. 2018

Sci Rep

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In this work, we experimentally investigate near-field capacitive coupling between a pair of single-gap split ring resonators (SRRs) in a terahertz metamaterial. The unit cell of our design comprises of two coupled SRRs with the split gaps facing each other. The coupling between two SRRs is examined by changing the gap of one resonator with respect to the other for several inter resonator separations. When split gap size of one resonator is increased for a fixed inter-resonator distance, we observe a split in the fundamental resonance mode. This split ultimately results in the excitation of narrow band low frequency resonance mode along with a higher frequency mode which gets blue shifted when the split gap increases. We attribute resonance split to the excitation of symmetric and asymmetric modes due to strong capacitive or electric interaction between the near-field coupled resonators, however blue shift of the higher frequency mode occurs mainly due to the reduced capacitance. The ability of near-field capacitive coupled terahertz metamaterials to excite split resonances could be significant in the construction of modulator and sensing devices beside other potential applications for terahertz domain.

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Probing the Near-Field Inductive Coupling in Broadside Coupled Terahertz Metamaterials

Cited by 23 publications

References 46 publications

Refractive index sensor based on fano-magnetic toroidal quadrupole resonance enabled by bound state in the continuum in all-dielectric metasurface

Refractive index sensor based on fano-magnetic toroidal quadrupole resonance enabled by bound state in the continuum in all-dielectric metasurface

Strong terahertz matter interaction induced ultrasensitive sensing in Fano cavity based stacked metamaterials

Modulating Fundamental Resonance in Capacitive Coupled Asymmetric Terahertz Metamaterials

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