Surface plasmons based terahertz modulator consisting of silicon–air–metal–dielectric–metal layers

Wang, Wei; Yang, Dongxiao; Qian, Zhenhai

doi:10.1016/j.optcom.2017.11.012

Cited by 7 publications

(2 citation statements)

References 31 publications

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“…The metasurface modulation device designed in ref. [112] produced a relatively large modulation depth by generating localized surface plasma peaks. The modulation performance of other types of modulators shown in Table 4 will not be described here.…”

Section: Silicon-based Amplitude Modulatormentioning

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: Silicon-based Amplitude Modulatormentioning

confidence: 99%

Terahertz Metasurface Modulators Based on Photosensitive Silicon

Zhou

et al. 2023

Laser & Photonics Reviews

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“…Localization of waves on the dielectric surface or interface is a common physical phenomenon, such as localization of surface plasmons (SPs) at a metal-dielectric interface, 1 and localization of Tamm plasmon polaritons (TPPs) at a uniformly periodic metal interface, 2 and in an anisotropic or isotropic Dyakonov state. 3 Although these local waves come from different origins, the property that exponential decay away from the interface is uniform.…”

Section: Introductionmentioning

confidence: 99%

Dynamically tunable bound states in the continuum supported by asymmetric Fabry–Pérot resonance

Gao

Liu

et al. 2022

Phys. Chem. Chem. Phys.

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Molecularization of Metasurfaces for Multifunctional Ultrafast All‐Optical Terahertz Waves

Zhou,

Qiu,

et al. 2024

Physica Status Solidi (a)

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Hybrid metasurfaces incorporated by active materials hold great promise for state‐of‐the‐art terahertz functional devices. However, it is still a major challenge to achieve ultrafast, dynamic, and multifunctional effective control of THz waves via hybrid metasurfaces. Herein, a modulator consisting of split rings and cut‐wires is first demonstrated, with an amplitude of −35.6 dB at 0.524 THz. By embedding semiconductor silicon into specified locations to form a hybrid metasurface, the ultrastrong connectivity of the silicon bridges leads to rapid optical molecularization. Under photoexcitation, the frequency tuning range is 26.7%, the phase shifting reaches 357.5°, and the maximal modulation depth is 94.54%. Taking advantage of the rapid relaxation of photocarriers in the silicon bridges, the ultrafast frequency switching is within 1400 ps. More interestingly, by changing the positions of the silicon bridges, the frequency tuning range is further promoted to 60%, the phase shifting is 353.5°, the modulation depth of 100% is achieved, and the full recovery time is 1600 ps. Furthermore, the underlying mechanism of the ultrafast tuning process is elucidated. This work demonstrates the feasibility of all‐optical‐controlled hybrid metasurface to achieve multifunctional dynamic modulation of THz waves, which has tremendous potential for applications in optical switching, signal processing, and frequency conversion.

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Surface plasmons based terahertz modulator consisting of silicon–air–metal–dielectric–metal layers

Cited by 7 publications

References 31 publications

Terahertz Metasurface Modulators Based on Photosensitive Silicon

Terahertz Metasurface Modulators Based on Photosensitive Silicon

Dynamically tunable bound states in the continuum supported by asymmetric Fabry–Pérot resonance

Molecularization of Metasurfaces for Multifunctional Ultrafast All‐Optical Terahertz Waves

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