Optical Controlled Terahertz Modulator Based on Tungsten Disulfide Nanosheet

Fan, Zhiyuan; Geng, Zhaoxin; Lv, Xudong; Su, Yue; Yang, Yuchen; Liu, Jian; Chen, Hongda

doi:10.1038/s41598-017-13864-5

Cited by 28 publications

(16 citation statements)

References 27 publications

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“…While many different approaches and devices for THz modulation have been demonstrated in existing literature, our approach offers a unique combination of characteristics. Modulation with superior bandwidth can be achieved with uniform heterostructures and films, but it is challenging to achieve low insertion loss and large modulation depths . Such large modulation depths can be achieved with tunable resonant structures, but the effect is typically not broadband .…”

Section: Resultsmentioning

confidence: 99%

Broadband electrically tunable VO₂‑Metamaterial terahertz switch with suppressed reflection

Schalch

Chi

et al. 2020

Micro & Optical Tech Letters

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Devices designed to dynamically control the transmission, reflection, and absorption of terahertz (THz) radiation are essential for the development of a broad range of THz technologies. A viable approach utilizes materials which undergo an insulator‐to‐metal transition (IMT), switching from transmissive to reflective upon becoming metallic. However, for many applications, it is undesirable to have spurious reflections that can scatter incident light and induce noise to the system. We present an electrically actuated, broadband THz switch which transitions from a transparent state with low reflectivity, to an absorptive state for which both the reflectivity and transmission are strongly suppressed. Our device consists of a patterned high‐resistivity silicon metamaterial layer that provides broadband reflection suppression by matching the impedance of free space. This is integrated with a VO2 ground plane, which undergoes an IMT by means of a DC bias applied to an interdigitated electrode. THz time domain spectroscopy measurements reveal an active bandwidth of 700 GHz with suppressed reflection and more than 90% transmission amplitude modulation with a low insertion loss. We utilize finite‐difference time domain (FDTD) simulations in order to examine the loss mechanisms of the device, as well as the sensitivity to polarization and incident angle. This device validates a general approach toward suppressing unwanted reflections in THz modulators and switches which can be easily adapted to a broad array of applications through straightforward modifications of the structural parameters.

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Section: Resultsmentioning

confidence: 99%

Broadband electrically tunable VO₂‑Metamaterial terahertz switch with suppressed reflection

Schalch

Chi

et al. 2020

Micro & Optical Tech Letters

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“…Common pump beams with wavelengths of 808 and 532 nm [18,[31][32][33][34], respectively, and silicon resistivity of 1000 Ω•cm were employed to simulate the THz modulation with different nanostructures. As is known, longer wavelengths have a stronger ability to penetrate silicon.…”

Section: Simulation Resultsmentioning

confidence: 99%

An Optically Tunable THz Modulator Based on Nanostructures of Silicon Substrates

Liu

Wei

et al. 2020

Sensors

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Nanostructures can induce light multireflection, enabling strong light absorption and efficient photocarrier generation. In this work, silicon nanostructures, including nanocylinders, nanotips, and nanoholes, were proposed as all-optical broadband THz modulators. The modulation properties of these modulators were simulated and compared with finite element method calculations. It is interesting to note that the light reflectance values from all nanostructure were greatly suppressed, showing values of 26.22%, 21.04%, and 0.63% for nanocylinder, nanohole, and nanotip structures, respectively, at 2 THz. The calculated results show that under 808 nm illumination light, the best modulation performance is achieved in the nanotip modulator, which displays a modulation depth of 91.63% with a pumping power of 60 mW/mm2 at 2 THz. However, under shorter illumination wavelengths, such as 532 nm, the modulation performance for all modulators deteriorates and the best performance is found with the nanohole-based modulator rather than the nanotip-based one. To further clarify the effects of the nanostructure and wavelength on the THz modulation, a graded index layer model was established and the simulation results were explained. This work may provide a further theoretical guide for the design of optically tunable broadband THz modulators.

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“…As seen in Figure 8a, the presence of MoS 2 on Si enhances the attenuation of the terahertz waves as compared to bare silicon under the same pumping power. Additionally, Fan et al [125] demonstrated a WS 2 -Si hybrid device, which operates as a broadband terahertz modulator. Carrier diffusion into MoS 2 from Si results in the enhancement of terahertz modulation in this heterostructure.…”

Section: Mos 2 -Si Hybrid For Terahertz Modulationmentioning

confidence: 99%

2D Materials for Terahertz Modulation

Gopalan

Sensale‐Rodriguez

2019

Advanced Optical Materials

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power consumption and minimizing cross-talk (maintain signal fidelity). As a result, terabit data communication can be made feasible with the help of broadband all-optical devices and circuits. [4] The technology for designing optical components and circuits operating at visible and NIR wavelengths has matured significantly over the last several decades, ensuring their widespread integration. While we can work toward improving data transmission rates of existing communication technology, shortage of spectral bandwidth for data transmission has become a looming problem over time. This has motivated researchers to seek out previously unused portions of the electromagnetic spectrum. The "terahertz gap" (≈30 µm-3 mm) has attracted considerable attention from researchers seeking to bridge the gap between the optical/IR and microwave spectrum. [5,6] Similar to the optical domain, the invention, optimization, and commercialization of discrete components such as sources, modulators, and detectors are necessary for the widespread use and integration of terahertz technologies. Electronic means of terahertz generation utilizing semiconductors (Si, GaAs) IMPATT [7] and Gunn diodes [8] have been developed. In conjunction with a frequency doubler/ tripler circuits, they typically operate on the lower end of the terahertz spectrum (0.1-1 THz); although the power output at higher frequency multiples might be significantly lower as compared to its fundamental mode. Additionally, InGaAs/ InP HBTs and InP HEMTs with cutoff frequencies >600 GHz have been demonstrated. [9,10] The advent of femtosecond lasers has paved the way for the generation of terahertz radiation via photoconductive switches, [11] photo-Dember effect [12,13] and nonlinear optical rectification in organic and inorganic crystals. [14][15][16] Femtosecond lasers have helped develop time domain terahertz systems that have been instrumental in ultrafast spectroscopy to study transient carrier dynamics of semiconductors. Development of terahertz quantum cascade lasers (THz-QCL) employing intersubband transitions in AlGaAs/GaAs quantum wells [17][18][19][20] is a notable milestone in terahertz lasing. In a complementary fashion, terahertz detection could be performed by electro-optic sampling in nonlinear crystals, [21] photoconductive antennas on low-temperature GaAs, [22,23] plasma wave oscillation in a field-effect channel, [24,25] etc. Finally, akin to the compact and economic components available at optical frequencies for the generation, manipulation, and detection, terahertz technology requires Terahertz waves spanning over the 0.1 to 10 THz region of the electromagnetic spectrum have attracted significant attention owing to a variety of potential applications such as short-range high-speed data transmission, noninvasive screening and detection, materials characterization, spectroscopy, etc. This has resulted in massive strides in the development of essential system components such as broadband terahertz sources, detector arrays with high responsivity, as well as...

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Optical Controlled Terahertz Modulator Based on Tungsten Disulfide Nanosheet

Cited by 28 publications

References 27 publications

Broadband electrically tunable VO₂‑Metamaterial terahertz switch with suppressed reflection

Broadband electrically tunable VO₂‑Metamaterial terahertz switch with suppressed reflection

An Optically Tunable THz Modulator Based on Nanostructures of Silicon Substrates

2D Materials for Terahertz Modulation

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Optical Controlled Terahertz Modulator Based on Tungsten Disulfide Nanosheet

Cited by 28 publications

References 27 publications

Broadband electrically tunable VO2‑Metamaterial terahertz switch with suppressed reflection

Broadband electrically tunable VO2‑Metamaterial terahertz switch with suppressed reflection

An Optically Tunable THz Modulator Based on Nanostructures of Silicon Substrates

2D Materials for Terahertz Modulation

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Product

Resources

About

Broadband electrically tunable VO₂‑Metamaterial terahertz switch with suppressed reflection

Broadband electrically tunable VO₂‑Metamaterial terahertz switch with suppressed reflection