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In the past decades, terahertz (THz) technology has made significant progress. However, multifunctional THz devices are still lacking, particularly low-cost and convenient ones. In this paper, we combine a multifunctional metasurface with the unique forward and backward emission characteristics of THz waves from a thin spintronic THz emitter (STEs), carefully designing two types of dual-band achromatic metasurfaces (DBAMs). In these two DBAMs, THz waves at 0.85 THz and 1 THz generated by the STE are focused on the same focal point. More importantly, one of the THz waves features a conventional focused wavefront, while the other exhibits a focused helical wavefront. Our design significantly expands the capabilities of metasurfaces and greatly advances the development of state-of-the-art multifunctional THz devices.
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http://dx.doi.org/10.1364/OL.554430 | DOI Listing |
Nano Lett
September 2025
Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea.
Active manipulation of terahertz (THz) waves is important for future optoelectronic applications, but most approaches rely on volatile or slow actuation, limiting efficiency and stability. Here, we report a nonvolatile, low-voltage tunable THz transmission device based on electrochemical modulation of a conductive polymer thin film integrated with metallic nanoresonators. A thin film of PEDOT:PSS, deposited via a single-step spin-coating process onto the nanoresonator array, enables efficient modulation of resonance-enhanced THz transmission with a gate voltage of less than 1 V.
View Article and Find Full Text PDFResearch (Wash D C)
August 2025
State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instruments, Tsinghua University, Beijing, China.
In recent years, important progress has been made in the field of biosensing and wireless communications by using metamaterials and metasurfaces. These technologies enable efficient manipulation of electromagnetic waves through judiciously designed subwavelength structural units. This review begins by focusing on the design and optimization of terahertz metasurface sensors, emphasizing their unique advantages in biomedical diagnostics.
View Article and Find Full Text PDFNat Commun
September 2025
State Key Laboratory of Precision Measurement Technology and Instruments, Tianjin University, Tianjin, China.
Phased arrays are crucial in various technologies, such as radar and wireless communications, due to their ability to precisely control and steer electromagnetic waves. This precise control improves signal processing and enhances imaging performance. However, extending phased arrays to the terahertz (THz) frequency range has proven challenging, especially for high-frequency operation, broadband performance, two-dimensional (2D) phase control with large antenna arrays, and flexible phase modulation.
View Article and Find Full Text PDFPhys Chem Chem Phys
September 2025
College of Materials Science and Engineering, Hohai University, Nanjing 210098, China.
The integration of terahertz (THz) technology with metasurfaces has attracted attention as it enables the fabrication of compact, high-performance, and tunable photonic devices. However, extensive investigation of metasurfaces was limited to a narrow THz range or manipulating a single mode of electromagnetic waves, absorption, reflection, or transmission, without achieving multi-band or broadband switching. This capability constrains metasurface adaptability in modern and reconfigurable systems.
View Article and Find Full Text PDFThermal terahertz (THz) sensors can detect broadband THz waves; however, they lack frequency selectivity, which hinders their application to spectroscopic measurements. In this study, we imparted frequency selectivity by including an antenna structure within the photo-thermo-electric (PTE) sensor. We used laser ablation to process a carbon nanotube film into a 100 $\upmu $m-scale wire-grid structure and generated a THz resonance in it.
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