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A reflective terahertz phase shifter for wide-range dynamic and continuous phase modulation is proposed. By injecting a tunable liquid crystal between the slotted metasurface and the grating microstructure, the phases of reflected waves can be modulated with different electrically driven methods. Numerical simulations show that the proposed terahertz phase shifter has a phase difference of more than 360° between unbiased and biased states. Furthermore, an array of 35×35 patch elements was designed and fabricated. The performance of the phase shifter provides more than 360° between 379.6 and 391.8 GHz, where the maximum phase shift reaches 422.4° at 385.9 GHz. Moreover, the fully electrically controlled phase modulation of more than 180° is achieved between 382.0 and 394.1 GHz, with a maximum phase modulation of 248.4° at 383.3 GHz. This work may provide a reflective terahertz phase modulator for beam steering.
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http://dx.doi.org/10.1364/AO.470935 | DOI Listing |
Nano Lett
September 2025
Department of Physics, The University of Tokyo, Hongo, Tokyo 113-0033, Japan.
On-chip terahertz (THz) spectroscopy has attracted growing attention because of its capability of measuring samples far smaller than the Rayleigh diffraction limit. The technique also allows the investigation of nonlinear responses of materials, which is indispensable for the development of ultrafast devices operating with a THz bandwidth. Here, we report the development of an on-chip THz-pump THz-probe spectroscopy technique that enables the study of ultrafast electrical-pulse-induced nonequilibrium phenomena.
View Article and Find Full Text PDFMicrosyst Nanoeng
September 2025
Center for Terahertz Waves, College of Precision Instrument and Optoelectronics Engineering, and the Key Laboratory of Optoelectronics Information and Technology (Ministry of Education), Tianjin University, Tianjin, 300072, China.
Terahertz communication systems demand versatile devices capable of simultaneously controlling propagating waves and surface plasmon polaritons (SPPs) in far-field (FF) and near-field (NF) channels, yet existing solutions are constrained by volatile operation, single-function limitations, and the inability to integrate NF and FF functionalities. Here, we present a nonvolatile reconfigurable terahertz metasurface platform leveraging the phase-change material GeSbTe(GST) to achieve on-demand dual-channel modulation-a first in the terahertz regime. By exploiting the stark conductivity contrast of GST between amorphous and crystalline states, our design enables energy-efficient switching between NF-SPP manipulation and FF-wavefront engineering without requiring continuous power input.
View Article and Find Full Text PDFDalton Trans
September 2025
School of Mathematics and Science, Southwest University of Science and Technology, Mianyang 621010, China.
In this paper, we design and study a temperature-controlled switchable terahertz perfect absorber based on vanadium dioxide (VO), which shows excellent multi-band performance, high sensitivity and intelligent thermal management. The device consists of four layers in a metal-dielectric composite structure, which are a metal reflection layer, silicon dielectric layer, VO phase change layer and top metal pattern layer from bottom to top. The simulation results show that when VO is in the low-temperature insulation state, the absorption rate of the device is as high as 99.
View Article and Find Full Text PDFiScience
September 2025
Center for Biophotonics, Institute of Medical Robotics, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China.
Ptychography is a phase imaging technique that leverages intensity images obtained by translating objects across an illumination beam. Deep learning has demonstrated promising potential in solving inverse problems, offering effective solutions for phase retrieval. However, obtaining substantial amounts of labeled data in the terahertz (THz) bands for pretraining the neural networks is very challenging, thereby limiting the generalization ability of the networks.
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.
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