In order to greatly promote impressive applications in terahertz (THz) photonics, research on active optoelectronic THz devices with high performance such as modulators is still a vital work. Electrically controlled THz modulators with a large modulation depth and wide modulation bandwidth are urgently needed for THz technology. Herein, a bismuth (Bi) nanofilm is rationally designed as an electrically controlled THz modulator combining the advantages of high electron mobility and near zero bandgap. The Bi nanofilm devices are produced by the magnetron sputtering deposition method, and the maximum modulation depth reaches 70% in the transmission spectrum. We have demonstrated an electrically tunable Bi nanofilm of modulating THz waves dynamically. Moreover, the Bi nanofilm modulator exhibits broadband modulation performance within a wide frequency range from 0.1 to 1.1 THz. Taking advantage of the excellent modulation property and simple approach to design, semimetal based devices are promising components for the development of high performance THz applications.

中文翻译：

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宽带电控铋纳米薄膜太赫兹调制器

为了极大地促进太赫兹 (THz) 光子学中令人印象深刻的应用，对调制器等高性能有源光电太赫兹器件的研究仍然是一项至关重要的工作。太赫兹技术迫切需要具有大调制深度和宽调制带宽的电控太赫兹调制器。在此，铋（Bi）纳米膜被合理设计为结合高电子迁移率和接近零带隙的优点的电控太赫兹调制器。Bi纳米薄膜器件采用磁控溅射沉积法生产，在透射光谱中最大调制深度达到70%。我们已经展示了一种动态调制太赫兹波的电可调 Bi 纳米膜。而且，Bi 纳米膜调制器在 0.1 至 1.1 THz 的宽频率范围内表现出宽带调制性能。利用优异的调制特性和简单的设计方法，半金属器件是开发高性能太赫兹应用的有前途的组件。