Topological and reconfigurable terahertz metadevices

Research Background

The terahertz (THz) frequency range, situated between microwave and infrared radiation, has emerged as a pivotal domain with broad applications in high-speed communication, imaging, sensing, and biosensing. The development of topological THz metadevices represents a notable advancement for photonic technologies, leveraging the distinctive electronic properties and quantum-inspired phenomena inherent to topological materials. These devices enable robust waveguiding capabilities, positioning them as critical components for on-chip data transfer and photonic integrated circuits, particularly within emerging 6G communication frameworks. A principal advantage resides in the capacity to maintain low-loss wave propagation while effectively suppressing backscattering phenomena, a critical requirement for functional components operating at higher frequencies. In parallel, by leveraging advanced materials such as liquid crystals, plasma, and phase-change materials, these devices facilitate real-time control over essential wave parameters, including amplitude, frequency, and phase, which augments the functionality of both communication and sensing systems, opening new avenues for THz-based technologies.

Research Progress

THz topological metadevices are subwavelength 2-dimensional artificial electromagnetic materials engineered with topological physics to enable robust wavefront control and lossless edge state propagation of THz waves. Their unique structures allow for the manipulation of THz waves to enhance the absorption and conversion efficiency of THz radiation into electrical signals. In particular, this device can be incorporated into integrated circuits to manipulate and detect THz waves on a chip scale, facilitating the development of compact and high-performance THz communication and imaging systems. The meta-atoms in the metadevices can be designed to resonate over a wide range of THz frequencies, enabling the detection of a broad spectrum of THz waves.

Reconfigurable THz devices overcome the inherent limitations of conventional static architectures by integrating external stimuli-responsive mechanisms. Through precise modulation via electric fields, thermal gradients, or optical excitation, these adaptive systems enable real-time control of beam steering, phase manipulation, polarization conversion, and spectral characteristic, demonstrating unprecedented operational flexibility and multifunctional capabilities. Specifically, compared with optical and thermal modulation methods, electrically modulated reconfigurable platforms have attracted wide interest due to their low cost, low energy consumption, and programmability. These dynamic platforms not only form the foundation for intelligent THz systems but also accelerate practical implementations in next-generation communications, real-time hyperspectral imaging, and advanced sensing technologies. Current reconfigurable THz devices fall into 4 categories: LC-based configurations, plasma-enhanced metadevices, and PCM-based architectures, and mechanically reconfigurable metadevices.

Future Outlook

Nevertheless, reconfigurable topological THz metadevices still face multiple technical barriers that need to be addressed. Future research will focus on 2 complementary strategies: on the one hand, the development of novel materials with enhanced switching dynamics and spectral response properties to improve THz frequency reconfigurability while reducing energy dissipa tion, and on the other hand, autonomous optimization of device architectures and adaptive control of signal modulation param eters through the integration of machine learning algorithms. Furthermore, the development of a novel advanced THz recon f igurable topological platform requires synergistic advances in materials innovation and fabrication processes, especially nanofabrication technology, which is crucial to achieve the complex geometries required for efficient electromagnetic wave manipulation.

Sources: https://spj.science.org/doi/10.34133/research.0882