The realm of technology is poised for a significant breakthrough, with the emergence of a groundbreaking carbon-based metasurface absorber that has the potential to revolutionize terahertz (THz) technology. Terahertz technology encompasses diverse applications including advanced sensing systems, biomedical imaging, and telecommunications, but has long been hampered by the absence of high-performance components that fully exploit its potential due to the unique nature of electromagnetic waves in the 0.1 to 10 THz range.
Recent advancements in metamaterials have opened up new possibilities for addressing these challenges. With the development of advanced manufacturing and processing technologies, researchers have been able to fabricate two-dimensional (2D) patterned microstructures with remarkable electromagnetic properties in the THz range, enabling unprecedented control over signals at these frequencies.
Despite numerous proposed 2D metamaterial absorbers, known as metasurfaces, many face significant limitations. A common drawback is the untunable nature of their electromagnetic performance once their structural design is finalized and produced. This lack of tunability restricts their potential applications. Although metal-based metasurface absorbers with the ability to be adjusted exist, they are discouraged due to challenges in production and subpar performance resulting from metal properties.
In response to these limitations, a research team led by Dr. Wenhan Cao of ShanghaiTech University in China has developed an innovative carbon-based tunable metasurface absorber with an exceptionally wide tunable bandwidth within the THz range, recently published in the Advanced Photonics Nexus journal.
This absorber utilises graphene and graphite microstructures as resonators and a graphite layer as a back-reflecting surface. The strategically designed unit cell of the absorber optimises absorption efficiency based on geometry, material properties, polarization sensitivity, and tuning mechanisms.
The absorber consists of three thin layers, including a simple dielectric layer, a patterned conductive layer made up of concentric graphite rings connected by graphene wires, and an absorption layer. This unique design facilitates exceptional absorption in the THz range, as well as tunability through the modification of the graphene layer’s Fermi level.
By adjusting the Fermi level through the application of voltage, the proposed absorber is capable of achieving an impressive bandwidth of 8.99 THz with over 90 percent absorption within the range of 7.24 to 16.23 THz. Furthermore, its insensitivity to the polarization angle of incident radiation is a significant advantage, making it an incredibly versatile and practical solution for a wide range of applications.
The potential of this revolutionary technology extends beyond its wide absorption bandwidth and tunable nature. Its ultra-thin, metal-free structure enhances its applicability and represents a significant advancement in THz technology.
Dr. Wenhan Cao envisions a future where THz devices become commonplace in various fields, from communications and medicine to biology and materials science. This development marks a major milestone in the quest to unleash the full potential of THz technology and its myriad of applications.
With the newly published research driving the advancement of carbon-based ultrabroadband tunable terahertz metasurface absorbers, the landscape of the THz industry is set to undergo a profound transformation, paving the way for a new era of cutting-edge technological applications.
Reference:
Nie, A., et al. (2024). Carbon-based ultrabroadband tunable terahertz metasurface absorber. SPIE Digital Library. doi.org/10.1117/1.APN.3.1.016007. Retrieved from https://spie.org/
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