Graphene-based terahertz optoelectronics

Zhou, Qiangguo; Qiu, Qinxi; Huang, Zhiming

doi:10.1016/j.optlastec.2022.108558

Cited by 27 publications

(6 citation statements)

References 170 publications

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“…Graphene is used in a variety of functional devices due to its many special physical properties, including extremely high electron mobility at RT and pressure, unique optical properties, superior mechanical and thermal properties, and the quantum Hall effect that can be observed at RT. [117] Graphene can be regarded as a no bandgap semiconductor, and the graphene carrier concentration and Fermi energy level can be effectively changed by chemical or electrostatic doping. [118] The conductivity of graphene (𝜎(𝜔)) can be obtained from the extended Kubo formula.…”

Section: Graphene-based Amplitude Modulatorsmentioning

confidence: 99%

Terahertz Metasurface Modulators Based on Photosensitive Silicon

Zhou

et al. 2023

Laser & Photonics Reviews

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Metasurfaces solve the lack of materials in the terahertz (THz) band and control precisely the amplitude, phase, polarization, and transmission characteristics of THz waves, providing an effective way to realize THz functional devices. This article focuses on the design of THz metasurface modulators with a unit structure consisting of metal square rings, including resonance frequency, phase, and amplitude modulators. By embedding photosensitive semiconductor silicon (Si) in the unit structure, the unit structure is built from meta‐atom to molecularization model under the optical pumping condition, and the resonance frequencies are switched between high and low frequencies. The resonance frequency switchable characteristic is demonstrated using the equivalent LC oscillation circuit model, and the theoretical calculation results agree well with the simulations. Through theoretical calculations, the modulators achieve ultrafast switching times of less than 0.141 ps by the optical pumps, which have significant advantages in ultrafast THz modulators. By continuing to change the embedded position of the silicon in the unit structure, not only is a wide range of THz phase modulation achieved, but also multilevel modulation of the phase is realized. It is found that there is a strong relationship between the modulation depth and phase variation of THz waves, and a reasonable analysis is given. Further the amplitude modulator with a larger modulation depth (MD) is developed, and when the conductivity of photosensitive semiconductor silicon (σSi) reaches 2.5 × 106 S m−1, return loss (RL) is ≈0 dB, and the maximum MD reaches ≈100%; in order to gain insight into the nature of modulation, the modulation mechanism of THz waves under optical pumping conditions is analyzed. In addition, graphene‐based THz metasurface amplitude modulators are designed. When the depth of amplitude modulation is achieved by bias voltage modulation of the Fermi energy level of graphene, the maximum modulation amplitude is 23.42 dB, with a minimal modulation accuracy of 0.05 THz eV−1. In the article, the designed modulators have extremely excellent modulation performance. It has great potential applications in silicon‐based THz photonic devices, ultrahigh frequency electronic devices, high sensitivity sensors, and high‐precision imaging.

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Section: Graphene-based Amplitude Modulatorsmentioning

confidence: 99%

Terahertz Metasurface Modulators Based on Photosensitive Silicon

Zhou

et al. 2023

Laser & Photonics Reviews

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“…However, traditional MMs devices, reliant on their intrinsic structural properties, suffer from large size, difficulty in integration, narrow bandwidth, low efficiency, and single functionality, and once designed, their performance cannot be easily altered after production, severely limiting their practical applications 17 . To address these issues, materials with tunable properties have been designed into THz MMs devices, such as graphene 18,19 , vanadium dioxide (VO2) 20 , diodes 21 , black phosphorus 22 , photosensitive silicon [23][24][25] , liquid crystals 26 , and Dirac semimetals 27 .…”

Section: Introductionmentioning

confidence: 99%

Deep neural network-enabled Multifunctional switchable terahertz metamaterial devices

Li,

Cai,

Chen

et al. 2024

Preprint

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Under the support of deep neural networks (DNN), a multifunctional switchable terahertz metamaterial (THz MMs) device is designed and optimized. This device not only achieves ideal ultra-wideband (UWB) absorption in the THz frequency range but enables dual-functional polarization transformation over UWB. When vanadium dioxide (VO2) is in the metallic state, the device as a UWB absorber with an absorption rate exceeding 90% in the 2.43 ~ 10 THz range, with a relative bandwidth (RBW) of 145.2%, and its wideband absorption performance is insensitive to polarization. When VO2 is in the insulating state, the device can switch to a polarization converter, achieving conversions from linear to cross polarization and from linear to circular polarization in the ranges of 4.58 ~ 10 THz and 4.16 ~ 4.43 THz, respectively. Within the 4.58 ~ 10 THz range, the polarization conversion ratio approaches 100% with an RBW of 74.3%, the polarization rotation angle is near 90°. Within the 4.16 ~ 4.43 THz range, the RBW is 6.29% and the ellipticity ratio approaches 1, Moreover, the effects of incident angle and polarization angle on the operational characteristics are studied. This THz MMs due to its advantages of wide angle, broad bandwidth, and high efficiency, provides valuable references for the research of new multifunctional THz devices.

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“…Graphene as a two-dimensional material has been widely used in recent years [ 15 ]. Combining terahertz metasurfaces with graphene can provide a novel way to solve these problems because of its unique optoelectronic properties [ 16 ]. When designing high-performance terahertz sensor devices, the properties of the relevant material are crucial.…”

Section: Introductionmentioning

confidence: 99%

Advances in terahertz metasurface graphene for biosensing and application

Yang

You

2023

Discover Nano

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Based on the extraordinary electromagnetic properties of terahertz waves, such as broadband, low energy, high permeability, and biometric fingerprint spectra, terahertz sensors show great application prospects in the biochemical field. However, the sensitivity of terahertz sensing technology is increasingly required by modern sensing demands. With the development of terahertz technology and functional materials, graphene-based terahertz metasurface sensors with the advantages of high sensitivity, fingerprint identification, nondestructive and anti-interference are gradually gaining attention. In addition to providing ideas for terahertz biosensors, these devices have attracted in-depth research and development by scientists. An overview of graphene-based terahertz metasurfaces and their applications in the detection of biochemical molecules is presented. This includes sensor mechanism research, graphene metasurface index evaluation, protein and nucleic acid sensors, and other chemical molecule sensing. A comparative analysis of graphene, nanomaterials, silicon, and metals to develop material-integrated metasurfaces. Furthermore, a brief summary of the main performance results of this class of devices is presented, along with suggestions for improvements to the existing shortcoming.

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Graphene-based terahertz optoelectronics

Cited by 27 publications

References 170 publications

Terahertz Metasurface Modulators Based on Photosensitive Silicon

Terahertz Metasurface Modulators Based on Photosensitive Silicon

Deep neural network-enabled Multifunctional switchable terahertz metamaterial devices

Advances in terahertz metasurface graphene for biosensing and application

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