Article
Chemistry, Multidisciplinary
Prakash Pitchappa, Abhishek Kumar, Saurav Prakash, Hariom Jani, Rohit Medwal, Mayank Mishra, Rajdeep Singh Rawat, Thirumalai Venkatesan, Nan Wang, Ranjan Singh
Summary: Phase change materials offer unique reconfigurable properties for photonic applications, with challenges in achieving large area reversible switching. By exploiting the semiconducting nature of GST, dynamic control of terahertz can be achieved at picosecond timescales.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Meng Lian, Ying Su, Kuan Liu, Shoujun Zhang, Xieyu Chen, Haonan Ren, Yihan Xu, Jiajia Chen, Zhen Tian, Tun Cao
Summary: Researchers have achieved switchable and wearable reflection linear polarization conversion in the THz frequency band. By changing the structural state of the material, the converter can continuously adjust the polarization conversion ratio. This switchable converter provides new possibilities for dynamically controlling THz polarization states and has wide applications in THz imaging, spectroscopy, and communications.
ADVANCED OPTICAL MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Ying Zeng, Junqin Wang, Xiaosheng Yang, Jianquan Yao, Peining Li, Qiang He, Ming Xu, Xiangshui Miao
Summary: Chalcogenide phase change materials (PCMs) are being studied for their nonvolatile phase transition capability and high dielectric tunability for optoelectronic applications. In this study, the terahertz modulation of germanium telluride (GeTe) thin films was experimentally demonstrated through THz time-domain spectroscopy (THz-TDS) and ultrafast time-resolved optical pump-THz probe experiments. The GeTe film showed high optical contrast and the transmission could be tuned from 95% to 35% in the range of 0.1-1.2 THz.
Article
Materials Science, Multidisciplinary
Han Jing, Zhong Min
Summary: Electromagnetically induced transparency (EIT) effect provides a vast space for the development of new optical devices. This study proposes and verifies an all-dielectric metamaterial based on the EIT effect. The amplitude and resonant frequency of the transmission window can be actively controlled, and the group delay can be switched. The frequency selectivity can be achieved by changing the diameter of the silicon array, and the resonant frequency can be shifted by immersing the sample in oil with different refractive indices. The metamaterial sample shows potential applications in various fields such as light buffering, 6G/terahertz communications, and ultrafast devices.
Article
Chemistry, Multidisciplinary
Ming Zhang, Peng Dong, Yu Wang, Baozhu Wang, Lin Yang, Ruihong Wu, Weimin Hou, Junyao Zhang
Summary: In this paper, a design for THz tunable wavefront manipulation achieved by the combination of plasmonic metasurface and phase change materials (PCMs) is proposed. The design allows for tunable reflective anomalous beam deflector and focusing metalens by utilizing the phase difference between the amorphous and crystalline states.
Article
Nanoscience & Nanotechnology
Maxime Pinaud, Georges Humbert, Sebastian Engelbrecht, Lionel Merlat, Bernd M. Fischer, Aurelian Crunteanu
Summary: Chalcogenide phase change materials (PCMs) with broadband responses and nonvolatile and reversible transitions have been investigated for their potential in controlling THz waves. The optical control of specific states of germanium telluride (GeTe) PCM has been demonstrated, showing promise for future optically reconfigurable THz devices with high functionality. Experimentally confirmed all dielectric GeTe-based THz polarizers present broadband responses and high extinction ratios, indicating potential for future disruptive developments in THz wave manipulation.
Review
Nanoscience & Nanotechnology
Hongxin Zeng, Sen Gong, Lan Wang, Tianchi Zhou, Yaxin Zhang, Feng Lan, Xuan Cong, Luyang Wang, Tianyang Song, YunCheng Zhao, Ziqiang Yang, Daniel M. Mittleman
Summary: Terahertz phase modulation is a current research hotspot and plays an important role in wireless communication, imaging, and radar systems. Significant progress has been made in this field, involving two major categories of phase modulators: free space and guided wave integration. Future trends include new methods and broader application requirements.
Article
Nanoscience & Nanotechnology
Maria R. Konnikova, Maxim D. Khomenko, Andrey S. Tverjanovich, Sergei Bereznev, Anna A. Mankova, Olga D. Parashchuk, Ivan S. Vasilevsky, Ilya A. Ozheredov, Alexander P. Shkurinov, Eugene A. Bychkov
Summary: This study investigates the optical characteristics and THz dielectric permittivity of GeTe2, a novel phase change material prepared by pulsed laser deposition. The study shows a significant difference in conductivity between the crystalline and amorphous states, with a 7-order magnitude contrast. By using GeTe2 PLD films, a THz metasurface in the form of a periodic structure is designed and prepared, which allows for the tuning of THz resonance through thermal control or light-induced crystallization response, achieving dynamic and tunable functionality. The intensity characteristics of the Raman peak at 155 cm(-1) are proposed to be used for controlling the state of the metasurface. Density functional theory (DFT) modeling demonstrates a decrease and disappearance of the 155 cm(-1) mode intensity, which is assigned to Te-Te stretching in amorphous chain fragments, during the crystallization process.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Optics
Shoujun Zhang, Xieyu Chen, Kuan Liu, Haiyang Li, Yuehong Xu, Xiaohan Jiang, Yihan Xu, Qingwei Wang, Tun Cao, Zhen Tian
Summary: This article introduces a nonvolatile, reconfigurable, and dynamic Janus metasurface using phase-change material Ge2Se2Te5 (GST) in the terahertz (THz) regime. The reversible switching characteristic of GST on large areas is demonstrated, and a multiplex metasurface scheme is proposed. Various applications such as dynamic beam splitter, bifocal metalens, and switchable metalens/focusing optical vortex generators are designed and experimentally characterized. The development of multifunctional and compact THz devices can be facilitated by this scheme.
PHOTONICS RESEARCH
(2022)
Article
Optics
Jiayue Liu, Fei Fan, Zhiyu Tan, Huijun Zhao, Jierong Cheng, Shengjiang Chang
Summary: In this work, we demonstrated an all-dielectric cascaded metasurface consisting of a spin-decoupled metasurface and a PB metasurface. The design achieves manipulation of terahertz (THz) beams, including the disruption of diffraction characteristics of the complementary spin beams and power modulation. This work opens up new avenues for the design of ultra-compact multifunctional devices.
Article
Multidisciplinary Sciences
June Sang Lee, Nikolaos Farmakidis, C. David Wright, Harish Bhaskaran
Summary: This study introduces hybridized-active-dielectric nanowires for polarization-selective tunability and demonstrates the ability to modulate conductance and perform matrix-vector multiplication using polarization as a parameter. This concept can be generalized to other materials and has potential in various applications.
Review
Multidisciplinary Sciences
Joo Hwan Ko, Young Jin Yoo, Yubin Lee, Hyeon-Ho Jeong, Young Min Song
Summary: The development of photonics has entered a new stage, where reconfigurable platforms with tunable functions are used to achieve versatile applications. Recent research has focused on integrating optically active materials into photonic platforms to dynamically control optical properties. This review explores the potential uses of tunable photonics in five application areas: structural coloration, metasurface for flat optics, photonic memory, thermal radiation, and terahertz plasmonics, and provides guidelines for designing tunable photonics based on wavelength characteristics.
Article
Physics, Applied
Yuan Li, He Ma, Yu Wang, Jun Ding, Limei Qi, Yulan Fu, Ran Ning, Lu Rong, Dayong Wang, Xinping Zhang
Summary: With the growing need for broadband wireless communication, high-resolution radar, security inspection, and biological analysis, terahertz (THz) technology has made significant progress in recent years. This progress has been possible due to the development of various THz functional devices, with metasurface being widely applied in these devices. However, constructing flexible THz metasurface devices remains a challenge due to the lack of flexibility in traditional semiconductor and metal materials. In this study, a two-dimensional material called MXene was used to create flexible metasurfaces with frequency filtering and polarization functions. These metasurfaces, combined with vanadium dioxide, showed excellent amplitude modulation performance under electrical stimulation. The flexibility and high integration of this active metasurface make it useful in THz imaging and sensing systems.
APPLIED PHYSICS LETTERS
(2022)
Article
Nanoscience & Nanotechnology
Tongtong Kang, Zongwei Ma, Jun Qin, Zheng Peng, Weihao Yang, Taixing Huang, Shilin Xian, Shuang Xia, Wei Yan, Yucong Yang, Zhigao Sheng, Jian Shen, Chaoyang Li, Longjiang Deng, Lei Bi
Summary: This paper reports on active metasurfaces based on Au/VO2 that demonstrate high transparency, high power efficiency, ultrafast switching, and large-scale fabrication capability. Fabricated using polystyrene sphere colloidal crystal self-assembly, these centimeter-scale Au/VO2 metasurfaces exhibit excellent optical modulation performance in static heating experiments and ultrafast pump-probe experiments. The alignment of surface plasmon resonance wavelength with the pump wavelength enables swift switching effects, showcasing a practical approach to fabricating large-scale and power-efficient active metasurfaces for ultrafast optical modulation.
Article
Nanoscience & Nanotechnology
Tongtong Kang, Zongwei Ma, Jun Qin, Zheng Peng, Weihao Yang, Taixing Huang, Shilin Xian, Shuang Xia, Wei Yan, Yucong Yang, Zhigao Sheng, Jian Shen, Chaoyang Li, Longjiang Deng, Lei Bi
Summary: This study reports on active metasurfaces based on Au/VO2, which exhibit high performance in optical modulation. These metasurfaces, fabricated by self-assembly, demonstrate high transparency, high power efficiency, ultrafast switching speed, and large-scale manufacturing capability, making them suitable for ultrafast optical modulation applications.
