Two-dimensional (2D) materials with layered structures have a variety of exceptional electronic and optical attributes for potentially developing basic functions of light wave technology from light-emitting to -modulating and -sensing. Here, we present state-of-the-art 2D materials-enabled optical intensity modulators according to their operation spectral ranges, which are mainly determined by the optical bandgaps of the 2D materials. Leveraging rich electronic structures from different 2D materials and the governed unique light–matter interactions, the working mechanisms and device architectures for the enabled modulators at specific wavelength ranges are discussed. For instance, the tunable excitonic effect in monolayer transition metal dichalcogenides allows the modulation of visible light. Electro-absorptive and electro-refractive graphene modulators could be operated in the telecom-band relying on their linear dispersion of the massless Dirac fermions. The bendable electronic band edge of the narrow bandgap in few-layer black phosphorus promises the modulation of mid-infrared light via the quantum-confined Franz–Keldysh or Burstein–Moss shift effect. Electrically and magnetically tunable optical conductivity in graphene also supports the realizations of terahertz modulators. While these modulators were demonstrated as proof of concept devices, part of them have great potential for future realistic applications, as discussed with their wavelength coverage, modulation depth, insertion loss, dynamic response speed, etc. Specifically, benefiting from the well-developed technologies of photonic chips and optical fibers in telecom and datacom, the 2D materials-based modulators integrated on these photonic structures are expected to find applications in fiber and chip optical communications. The free-space mid-infrared and terahertz modulators based on 2D materials can expect application in chemical bond spectroscopy, free-space communications, and environment/health sensing.

中文翻译：

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支持二维材料的光调制器：从可见光到太赫兹光谱范围

具有分层结构的二维 (2D) 材料具有各种特殊的电子和光学属性，可用于开发光波技术从发光到调制和传感的基本功能。在这里，我们根据二维材料的工作光谱范围展示了最先进的支持二维材料的光强度调制器，这主要由二维材料的光学带隙决定。利用来自不同二维材料的丰富电​​子结构和受控的独特光-物质相互作用，讨论了特定波长范围内启用调制器的工作机制和器件架构。例如，单层过渡金属二硫化物中的可调谐激子效应允许调制可见光。电吸收和电折射石墨烯调制器可以依靠它们对无质量狄拉克费米子的线性色散在电信频段中运行。少层黑磷中窄带隙的可弯曲电子带边缘有望通过量子限制 Franz-Keldysh 或 Burstein-Moss 位移效应调制中红外光。石墨烯中电学和磁学可调的光导率也支持太赫兹调制器的实现。虽然这些调制器被展示为概念验证设备，但其中一部分在未来的实际应用中具有巨大的潜力，正如它们的波长覆盖范围、调制深度、插入损耗、动态响应速度等所讨论的那样。具体来说，受益于电信和数据通信中光子芯片和光纤的成熟技术，集成在这些光子结构上的基于二维材料的调制器有望在光纤和芯片光通信中得到应用。基于二维材料的自由空间中红外和太赫兹调制器有望应用于化学键光谱、自由空间通信和环境/健康传感。