Investigation of Phonon Scattering on the Tunable Mechanisms of Terahertz Graphene Metamaterials

He, Xiaoyong; Lin, Fangting; Liu, Feng; Zhang, Hao

doi:10.3390/nano10010039

Cited by 54 publications

(25 citation statements)

References 42 publications

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“…However, all-dielectric quasi-BIC metasurfaces with independently tunable resonance amplitude and frequency have rarely been reported, which increases their applicability for multidimensional manipulation of THz waves. Since the surface conductivity can be tuned via shifting Fermi level under external bias voltage, graphene is commonly used in active THz metamaterials devices [34][35][36] and it is a good method to incorporate graphene with dielectric metasurfaces for active tunability [37]. Furthermore, phase-change materials are capable of providing great variations in material properties during the phase transition and can be used to design dynamic THz devices [38,39].…”

Section: Introductionmentioning

confidence: 99%

Tunable Bound States in the Continuum in All-Dielectric Terahertz Metasurfaces

Chen

Wang

2020

Nanomaterials

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In this paper, a tunable terahertz dielectric metasurfaces consisting of split gap bars in the unit cell is proposed and theoretically demonstrated, where the sharp high-quality Fano resonance can be achieved through excitation of quasi-bound states in the continuum (quasi-BIC) by breaking in-plane symmetry of the unit cell structure. With the structural asymmetry parameter decreasing and vanishing, the calculated eigenmodes spectra demonstrate the resonance changes from Fano to symmetry-protected BIC mode, and the radiative quality factors obey the inverse square law. Moreover, combining with graphene monolayer and strontium titanate materials, the quasi-BIC Fano resonance can be tuned independently, where the resonance amplitude can be tuned by adjusting the Fermi level of graphene and the resonance frequency can be tuned by controlling the temperature of strontium titanate materials. The proposed structure has numerous potential applications on tunable devices including modulators, switches, and sensors.

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Section: Introductionmentioning

confidence: 99%

Tunable Bound States in the Continuum in All-Dielectric Terahertz Metasurfaces

Chen

Wang

2020

Nanomaterials

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“…Graphene has promising potential in fabricating phototransistors and photodetectors owing to its unique band structure with prominent optoelectronic and charge transport properties [1][2][3] . Tremendous prospects have emerged in transparent devices 4,5 , silicon compatible devices 6 , and optical modulators [7][8][9] . However, the inferior light absorption of single atomic layer graphene limits the phototransistor performance 10 .…”

Section: Introductionmentioning

confidence: 99%

Light-modulated vertical heterojunction phototransistors with distinct logical photocurrents

Han

Yang

et al. 2020

Light Sci Appl

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The intriguing carrier dynamics in graphene heterojunctions have stimulated great interest in modulating the optoelectronic features to realize high-performance photodetectors. However, for most phototransistors, the photoresponse characteristics are modulated with an electrical gate or a static field. In this paper, we demonstrate a graphene/C60/pentacene vertical phototransistor to tune both the photoresponse time and photocurrent based on light modulation. By exploiting the power-dependent multiple states of the photocurrent, remarkable logical photocurrent switching under infrared light modulation occurs in a thick C60 layer (11 nm) device, which implies competition of the photogenerated carriers between graphene/C60 and C60/pentacene. Meanwhile, we observe a complete positive-negative alternating process under continuous 405 nm irradiation. Furthermore, infrared light modulation of a thin C60 (5 nm) device results in a photoresponsivity improvement from 3425 A/W up to 7673 A/W, and we clearly probe the primary reason for the distinct modulation results between the 5 and 11 nm C60 devices. In addition, the tuneable bandwidth of the infrared response from 10 to 3 × 103 Hz under visible light modulation is explored. Such distinct types of optical modulation phenomena and logical photocurrent inversion characteristics pave the way for future tuneable logical photocurrent switching devices and high-performance phototransistors with vertical graphene heterojunction structures.

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“…Many peculiar functions have been realized, including holographic imaging, perfect absorption [9], and flat lenses [10]. Due to the rapid development of terahertz technology and its unique characteristics, it has also become a popular research topic in the field of metamaterials in recent years [11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Prediction Network of Metamaterial with Split Ring Resonator Based on Deep Learning

et al. 2020

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The introduction of "metamaterials" has had a profound impact on several fields, including electromagnetics. Designing a metamaterial's structure on demand, however, is still an extremely time-consuming process. As an efficient machine learning method, deep learning has been widely used for data classification and regression in recent years and in fact shown good generalization performance. We have built a deep neural network for ondemand design. With the required reflectance as input, the parameters of the structure are automatically calculated and then output to achieve the purpose of designing on demand. Our network has achieved low mean square errors (MSE), with MSE of 0.005 on both the training and test sets. The results indicate that using deep learning to train the data, the trained model can more accurately guide the design of the structure, thereby speeding up the design process. Compared with the traditional design process, using deep learning to guide the design of metamaterials can achieve faster, more accurate, and more convenient purposes.

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Investigation of Phonon Scattering on the Tunable Mechanisms of Terahertz Graphene Metamaterials

Cited by 54 publications

References 42 publications

Tunable Bound States in the Continuum in All-Dielectric Terahertz Metasurfaces

Tunable Bound States in the Continuum in All-Dielectric Terahertz Metasurfaces

Light-modulated vertical heterojunction phototransistors with distinct logical photocurrents

Prediction Network of Metamaterial with Split Ring Resonator Based on Deep Learning

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