Article
Chemistry, Multidisciplinary
Yuehong Xu, Quan Xu, Xueqian Zhang, Xi Feng, Yongchang Lu, Xixiang Zhang, Ming Kang, Jiaguang Han, Weili Zhang
Summary: This study proposes a new design scheme using all-metal stereo U-shaped meta-atoms for efficient and broadband manipulation of terahertz polarization. The design is experimentally verified to demonstrate superior performance in polarization control and enriches the design freedom of polarization-related metasurfaces.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Nanoscience & Nanotechnology
Christopher Rathje, Rieke von Seggern, Leon A. Graeper, Jana Kredl, Jakob Walowski, Markus Muenzenberg, Sascha Schaefer
Summary: In this study, we demonstrate a spatial mapping technique for the coupling strength between a micrometer-scale terahertz source on a spintronic emitter and far-field light mediated by a structured metallic environment. Experimental results are reproduced by a numerical model, providing insights into the microscopic coupling mechanisms. The technique can be applied to extract the THz mode structure, enabling tailored spectral and angular emission profiles for planar THz sources.
Article
Optics
Sang-Hyuk Park, Sehyuk Lee, Kunie Ishioka, Christopher J. Stanton, Chul-Sik Kee, Andreas Beyer, Ulrich Hoefer, Wolfgang Stolz, Kerstin Volz, Young-Dahl Jho
Summary: We report on a new mechanism of THz electromagnetic emission, which involves the deformational coupling of acoustic phonons and electrons in non-polar Si propagation medium. Local modulation of the bandgap by propagating acoustic phonon pulses induces abrupt drift motion at the depletion edge of Si, resulting in the simultaneous emission of delayed THz bursts.
Article
Optics
Yan Wang, Shaohe Li, Hui Wang, Bowen Tan, Xingcheng Xiang, Runfeng Su, Caihong Zhang, Biaobing Jin, Jian Chen, Peiheng Wu
Summary: PB metasurfaces show superior performance in the THz region with an ultra-thin structure, achieving broadband and efficient wavefront manipulation. By spatially rotating orientation, beam steering and superposition of vortex waves can be achieved.
Article
Multidisciplinary Sciences
Nanli Mou, Bing Tang, Jingzhou Li, Hongxing Dong, Long Zhang
Summary: Researchers have developed a thermally switchable terahertz metasurface that can achieve high transmission and ultra-broadband absorption at different temperatures, making it insensitive to the incident angle. The structure is highly scalable and has potential applications in areas such as optical switching, terahertz imaging, and filtering.
SCIENTIFIC REPORTS
(2022)
Article
Chemistry, Multidisciplinary
Yunfeng Chen, Wanli Ma, Congwei Tan, Man Luo, Wei Zhou, Niangjuan Yao, Hao Wang, Lili Zhang, Tengfei Xu, Tong Tong, Yong Zhou, Yongbing Xu, Chenhui Yu, Chongxin Shan, Hailing Peng, Fangyu Yue, Peng Wang, Zhiming Huang, Weida Hu
Summary: Bi2O2Se antenna-assisted photodetector shows great potential in broadband detection, achieving wide spectral detection from IR to THz ranges. The multi-mechanism of electromagnetic waves to electrical conversion enables high responsivity in different frequency bands.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Physics, Applied
Yuxuan Wei, Jiaming Le, Li Huang, Chuanshan Tian
Summary: This work presents a convenient approach to generate strong broadband terahertz (THz) pulses with a tunable center frequency using low-cost crystalline quartz. The THz conversion efficiency in quartz reaches 0.05%, comparable to LiNbO3 at room temperature, while providing a much broader THz spectral range. This not only addresses the urgent need for a light source in nonlinear THz spectroscopy beyond 2 THz but also offers an alternative route in selecting nonlinear optical crystals for frequency conversion.
APPLIED PHYSICS LETTERS
(2023)
Article
Multidisciplinary Sciences
Junliang Dong, Alessandro Tomasino, Giacomo Balistreri, Pei You, Anton Vorobiov, Etienne Charette, Boris Le Drogoff, Mohamed Chaker, Aycan Yurtsever, Salvatore Stivala, Maria A. Vincenti, Costantino De Angelis, Detlef Kip, Jose Azana, Roberto Morandotti
Summary: The authors propose a new approach for independent processing of multiplexed signals in terahertz waveguides by engineering the metal surface of a four-wire waveguide.
NATURE COMMUNICATIONS
(2022)
Article
Optics
Zewen Wang, Qi Li, Fei Yan
Summary: This study proposes a design strategy for generating broadband terahertz ring-Airy beams using a transparent all-silicon metasurface. The amplitude and phase of the transmitted beam can be modulated by controlling the rotation angles of silicon pillars. The metasurface has a high transmission efficiency and exhibits abruptly autofocusing properties in the frequency range of 2.12 to 2.72 THz.
OPTICS AND LASER TECHNOLOGY
(2022)
Article
Optics
Ruoya Zhang, Yuehao Luo, Jike Xu, Huaying Wang, Haiyan Han, Dan Hu, Qiaofen Zhu, Yan Zhang
Summary: A tunable broadband terahertz absorber based on vanadium dioxide (VO2) has been proposed, showing excellent broadband absorption and advantages of polarization-insensitiveness and wide-angle absorption. Potential applications include modulators and photoelectric switches.
Article
Optics
Yan Teng, Chun Li, Shaochen Li, Yuhua Xiao, Ling Jiang
Summary: In this study, a method for designing terahertz random meta-surfaces based on deep Convolutional Neural Networks and genetic algorithms is proposed. The forward prediction model accurately predicts the reflection amplitude and phase response, with a calculation speed increased by 40,000 times compared to the Full-wave solver. By combining with genetic algorithms, the efficiency of the design is greatly improved, providing an efficient method for global optimization in complex designs.
OPTICS AND LASER TECHNOLOGY
(2023)
Article
Optics
Qiuming Zeng, Yi Huang, Shuncong Zhong, Tingting Shi, Jianxiong Chen, Yujie Zhong, Tingling Lin, Xuefeng Chen
Summary: This study presents an innovative method to achieve broadband filtering at terahertz frequencies by manipulating the interaction between two localized surface plasmon polariton modes using multiscale-coupled plasmonic fields. The integration of strong coupling and far-field interference expands the transmission range and enhances the capability of the double-layer metamaterial for broadband filtering.
OPTICS AND LASER TECHNOLOGY
(2024)
Article
Physics, Applied
Yan Wang, Shaohe Li, Hui Wang, Longcheng Feng, Bowen Tan, Yihui Tan, Runfeng Su, Jingbo Wu, Caihong Zhang, Biaobing Jin, Jian Chen, Peiheng Wu
Summary: This study demonstrates a broadband, ultrathin, and efficient metasurface-based asymmetric transmission and wavefront manipulation method in the terahertz region, which provides a promising route for applications such as information encryption, THz wireless communication, and spectroscopy.
APPLIED PHYSICS LETTERS
(2022)
Article
Nanoscience & Nanotechnology
Li Niu, Quan Xu, Xueqian Zhang, Ziying Zhang, Shaoxian Li, Xieyu Chen, Yuehong Xu, Jiajun Ma, Ming Kang, Jiaguang Han, Weili Zhang
Summary: Efficient manipulation of electromagnetic waves using metasurfaces has been a focus of research, with the introduction of meta-coupling effects providing further physical insights in wave control. This strategy allows for efficient tuning of reflection phase shift without changing resonator dimensions, enabling the design of high-efficiency metasurface deflectors. The proposed controlling strategy enriches design freedoms and may have broad applications in functional devices.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Review
Optics
Mohammad Ghazialsharif, Junliang Dong, Alaeddine Abbes, Roberto Morandotti
Summary: Waveguides are essential for future terahertz networks, providing high-speed data transmission and signal processing capabilities. Metal-wire waveguides have attracted attention due to their simplicity and promising characteristics, but manipulating the signals within them is challenging. Recent advances have resulted in signal processors with functions such as filtering, coupling, temporal integration, and multiplexing, with potential for real-time tunability and reconfigurability.
Article
Multidisciplinary Sciences
Kazuki Okamoto, Teppei Ebina, Naoki Fujii, Kuniaki Konishi, Yu Sato, Tetsuhiko Kashima, Risako Nakano, Hiroyuki Hioki, Haruki Takeuchi, Junji Yumoto, Masanori Matsuzaki, Yuji Ikegaya
Summary: The newly introduced Tb3+-doped glass material emits green fluorescence in biological experiments and is compatible with conventional research environments. Using micropipettes made of Tb3+-doped glass allows for various operations on GFP-labeled cells under real-time fluorescence microscopic control.
Article
Physics, Applied
Yuyuan Huang, Kuniaki Konishi, Momoko Deura, Yusuke Shimoyama, Junji Yumoto, Makoto Kuwata-Gonokami, Yukihiro Shimogaki, Takeshi Momose
Summary: A simple physical model was developed to evaluate the propagation loss of a metal-coated dielectric terahertz waveguide with different metal film thicknesses fabricated by three-dimensional printing and film coating techniques. The model considered the thickness-dependent electrical conductivity of the metal film and was validated using an in-house multi-channel Au-coated THz parallel-plate waveguide. The model clarified the contribution of three loss components to the overall loss and revealed the critical film thickness and its dependence on film quality for high-performance waveguides.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Physics, Applied
K. Yamada, Y. Tajima, T. Murayoshi, X. Fan, A. Ishida, T. Namba, S. Asai, M. Kuwata-Gonokami, E. Chae, K. Shu, K. Yoshioka
Summary: The proposed system utilizes an injection-locked pulsed laser with an electro-optic phase modulator in a Ti:sapphire laser cavity to achieve broadband optical spectra and long pulse durations. The output microsecond-long pulse is composed of a train of short pulses in the time domain and a comblike broadband spectrum with fast chirping in the frequency domain. The system shows promise for efficient Doppler cooling of positronium.
PHYSICAL REVIEW APPLIED
(2021)
Article
Physics, Applied
Yuyuan Huang, Kuniaki Konishi, Momoko Deura, Yusuke Shimoyama, Junji Yumoto, Makoto Kuwata-Gonokami, Yukihiro Shimogaki, Takeshi Momose
Summary: This study aimed to identify suitable metallic materials for constructing metal-coated dielectric terahertz (THz) waveguides. The researchers examined seven different metals and experimentally determined the propagation losses of their metal-coated waveguides. They developed a physical model to estimate key parameters influencing the performance of the waveguides and applied it to identify copper (Cu) as the optimal metal. The study also evaluated the impact of surface oxide layers on THz wave propagation and found that copper oxide had negligible effect.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Multidisciplinary Sciences
Yusuke Morita, Kosuke Yoshioka, Makoto Kuwata-Gonokami
Summary: A new type of Bose-Einstein condensate was observed in a trapped gas of 1s paraexcitons in bulk Cu2O below 400 mK, with a small condensate fraction of 0.016 and spatial profile described by mean-field theory. The condensate was undetectable by conventional luminescence spectroscopy, showing potential for understanding quantum statistical mechanics of non-equilibrium open systems.
NATURE COMMUNICATIONS
(2022)
Article
Physics, Applied
Masataka Kobayashi, Yusuke Arashida, Kanta Asakawa, Keisuke Kaneshima, Masashi Kuwahara, Kuniaki Konishi, Junji Yumoto, Makoto Kuwata-Gonokami, Jun Takeda, Ikufumi Katayama
Summary: Using high-repetition-rate single-shot spectroscopy and a laser microscope, we revealed the pulse-to-pulse ultrafast dynamics of energy relaxation in Ge2Sb2Te5 thin films. The study observed the transient transmittance change of the crystalline phase and the subsequent amorphous phase energy relaxation, leading to efficient energy relaxation and the formation of laser-induced periodic surface structures.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2023)
Article
Optics
Ryohei Yamada, Wataru Komatsubara, Haruyuki Sakurai, Kuniaki Konishi, Norikatsu Mio, Junji Yumoto, Makoto Kuwata-Gonokami
Summary: The utilization of sub-100 fs pulses is an attracting approach to improve femtosecond laser microfabrication. However, nonlinear propagation effects in air distort the beam's profile, making it difficult to predict the ablation crater shape. In this study, we developed a method using nonlinear propagation simulations to quantitatively predict the ablation crater shape. The method showed excellent agreement with experimental results for different pulse energies and revealed a correlation between simulated fluence and ablation depth.
Article
Materials Science, Multidisciplinary
J. Omachi, N. Naka, K. Yoshioka, M. Kuwata-Gonokami
Summary: In this study, we investigated the dynamic properties of the electron-hole state in electron-hole droplets (EHDs) using dielectric response measurements. We found that the surface plasmon resonance of EHDs and the electron-hole Coulomb interaction had a significant impact on the dynamic dielectric response. The carrier density inside EHDs remained constant, while the decay time of the condensed volume was short and the AC conductivity relaxation rate was the highest among group-IV semiconductors during the nanosecond timescale.
Article
Optics
Yiping Chen, Munekazu Horikoshi, Makoto Kuwata-Gonokami, Kosuke Yoshioka
Summary: In this study, a balanced noninteracting Bose gas was created using a Bose-Fermi mixture, and the critical point of noninteraction was determined. The results of this study are crucial for further understanding the properties of an ideal Bose gas in a harmonic trap.
Article
Materials Science, Multidisciplinary
Haruyuki Sakurai, Kuniaki Konishi, Hiroharu Tamaru, Junji Yumoto, Makoto Kuwata-Gonokami
Summary: This study develops a new method for analyzing laser ablation morphology without reducing data, spatially correlating the input beam profile and ablated morphology. It is beneficial for extracting well-studied values and dependencies, as well as probing the spatial independence of the process.
COMMUNICATIONS MATERIALS
(2021)
Article
Optics
A. Amani Eilanlou, Tomoya Okino, Yasuo Nabekawa, Makoto Kuwata-Gonokami, Katsumi Midorikawa
Summary: This study demonstrates the achievement of the highest intra-cavity pulse energy of 80 µJ in a Kerr lens mode-locked thin-disk ring laser oscillator at a repetition rate exceeding 10 MHz, allowing for direct observation of the 2nd and 3rd harmonic beams. By adding a tight focusing setup to the ring cavity, krypton gas flame could be observed at an intra-cavity peak intensity of approximately 28 TW/cm(2), resulting in a conversion efficiency of 10(-5) for the 3rd harmonic beam. Further improvements in the ring oscillator could lead to the realization of a table-top source of vacuum ultraviolet pulses for applications in photoelectron spectroscopy.
Article
Optics
Ryo Imai, Kuniaki Konishi, Junji Yumoto, Makoto Kuwata-Gonokami
Summary: This study demonstrates the fabrication of an optical waveguide with propagation loss below 1 dB/cm using an Yb:KGW femtosecond laser in fused silica. By controlling pulse energy and duration, the propagation loss achieved is comparable to that of a waveguide made using a Ti:Sapphire laser. It is also shown that nano-wrinkles and nano-pores, which cause losses, can be avoided in modified silica under certain conditions.
