Imagine a world where communication and imaging technologies are significantly faster and more precise. Researchers at Universiti Teknologi Malaysia (UTM) are bringing this vision closer to reality with a new breakthrough in metasurface design, paving the way for advanced terahertz applications.
Metasurfaces, artificially engineered materials with unique electromagnetic properties, are revolutionizing how we control and manipulate electromagnetic waves. Think of them as ultra-thin, customizable surfaces that can bend, focus, and shape light and other electromagnetic radiation in unprecedented ways. Terahertz waves, which lie between microwaves and infrared light on the electromagnetic spectrum, hold immense potential for improving communication speeds, enhancing medical imaging, and creating more sensitive security scanners. However, current terahertz metasurfaces are limited by their tunability; specifically, achieving a large enough phase change, which restricts their performance.
The UTM team, has developed a multi-bit programmable metasurface capable of terahertz beam steering, using an innovative physics-informed inverse design (PIID) approach. This algorithm integrates a modified coupled mode theory (MCMT) into residual neural networks. The PIID algorithm not only increases the design accuracy compared to conventional neural networks but also elucidates the intricate physical relations between the geometry and the modes. Their PIID algorithm overcomes design limitations by achieving an enhanced phase tuning as large as 300 degrees, all without reducing the reflection intensity of the signal.
To validate their design, the researchers experimentally tested the programmable beam steering metasurface. The device proved adaptable across various coding schemes (1-bit, 2-bit, and tri-state), achieving a deflection angle of up to 68 degrees and broadening the steering coverage. This improved beam steering capability translates to more precise control over terahertz waves, which is crucial for various applications.
This demonstration provides a promising pathway for rapidly exploring advanced metasurface devices. The implications are far-reaching, offering the potential to significantly enhance communication speeds by enabling faster data transmission. In imaging, this technology could lead to higher-resolution scans with improved contrast, benefiting medical diagnostics and security applications.
The UTM team’s breakthrough represents a significant step forward in terahertz technology. Future research will focus on further optimizing the design and exploring new materials to push the boundaries of what’s possible with metasurfaces. This innovation promises a future where terahertz technology transforms communication, imaging, and beyond.
DOI: https://doi.org/10.1016/j.asej.2025.103466
