A Review of THz Modulators with Dynamic Tunable Metasurfaces

Abstract

Terahertz (THz) radiation has received much attention during the past few decades for its potential applications in various fields, such as spectroscopy, imaging, and wireless communications. To use terahertz waves for data transmission in different application systems, the efficient and rapid modulation of terahertz waves is required and has become an in-depth research topic. Since the turn of the century, research on metasurfaces has rapidly developed, and the scope of novel functions and operating frequency ranges has been substantially expanded, especially in the terahertz range. The combination of metasurfaces and semiconductors has facilitated both new opportunities for the development of dynamic THz functional devices and significant achievements in THz modulators. This paper provides an overview of THz modulators based on different kinds of dynamic tunable metasurfaces combined with semiconductors, two-dimensional electron gas heterostructures, superconductors, phase-transition materials, graphene, and other 2D material. Based on the overview, a brief discussion with perspectives will be presented. We hope that this review will help more researchers learn about the recent developments and challenges of THz modulators and contribute to this field.

Metallic and dielectric metasurfaces in photoconductive terahertz devices: a review

“…It is also important to note that there are many other applications of the above-mentioned metasurfaces that lie beyond the scope of this review and that are not limited by PCAs. 126 For instance, metasurfaces can be configured for a variety of forms of light manipulation, including holograms, 127 polarization, 128 bending and focusing, 129,130 and invisible cloaks. 131,132 Concerning THz emission, different designs of the metallic metasurfaces can be used as a standalone THz emitter with no antenna metallization.…”

Terahertz Metasurfaces: Toward Multifunctional and Programmable Wave Manipulation

“…Small attenuation, strong penetration, and high time spectrum signal-to-noise ratio (SNR) also make terahertz wave itself suitable for imaging [2]. In addition, its wide instantaneous bandwidth promotes the implementation of highspeed communication [3]. As these advantages of terahertz spectrum are gradually recognized and accounted, series of terahertz devices have been proposed to regulate terahertz wavefronts [4][5][6], yet some devices need to face the large volume, high cost, and fabrication issue, which restrict their applications in terahertz scenarios.…”

High-precision digital terahertz phase manipulation within a multichannel field perturbation coding 2DEG meta-chip

“…Terahertz (THz) technology has potentially transformative applications in high-rate communication, biomedical imaging, holography, spectroscopy, radar and security [1][2][3][4][5][6][7][8][9][10][11][12][13] . As the demand for the wireless bandwidth increases, wireless communication systems applying terahertz waves as carriers provide ultrahigh transmission rates and low delays, which are expected to exceed those of 5G communication systems.…”