Article
Engineering, Electrical & Electronic
Davide Priante, Mingyang Zhang, Alexander R. Albrecht, Roman Bek, Michael Zimmer, Catherine L. Nguyen, David P. Follman, Garrett D. Cole, Mansoor Sheik-Bahae
Summary: This paper presents a detailed study on the performance of a membrane external-cavity surface-emitting laser (MECSEL) under different pumping configurations. The authors propose and implement an improved pumping scheme for in-well pumping, which achieves higher output power and efficiency.
IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS
(2022)
Review
Nanoscience & Nanotechnology
Taiichi Otsuji, Stephane Albon Boubanga-Tombet, Akira Satou, Deepika Yadav, Hirokazu Fukidome, Takayuki Watanabe, Tetsuya Suemitsu, Alexander A. Dubinov, Vyacheslav V. Popov, Wojciech Knap, Valentin Kachorovskii, Koichi Narahara, Maxim Ryzhii, Vladimir Mitin, Michael S. Shur, Victor Ryzhii
Summary: This paper reviews recent advancements in graphene-based plasmonic metamaterials for terahertz (THz) laser transistors. The researchers investigate various approaches using graphene plasmonic metamaterials to achieve room-temperature, dry-cell-battery operated intense THz lasing with fast direct modulation. The paper discusses device structures and design constraints for coherent light sources applicable to future THz wireless communication systems.
Article
Nanoscience & Nanotechnology
Mingming Feng, Baoqing Zhang, Haotian Ling, Zihao Zhang, Yiming Wang, Yilin Wang, Xijian Zhang, Pingrang Hua, Qingpu Wang, Aimin Song, Yifei Zhang
Summary: This paper presents a device that combines metal and graphene materials to achieve significant phase modulation of surface plasmon polaritons (SPPs). The experiment demonstrates that the cut-off frequency and phase of SPPs can be modulated by changing the chemical potential of graphene, and the transmittance is also controlled.
Article
Chemistry, Multidisciplinary
Liwei Xu, Yingyi Li, Jun Cai, Wanli Zhao, Tongyu Liu, Tongyu Dai, Youlun Ju, Yu Ding
Summary: This paper demonstrates the experimental results of a graphene passively Q-switched Nd:YAG laser pumped resonantly by an 885 nm laser diode (LD). In continuous-wave operation, the maximum average output power reaches 1.8 W with a slope efficiency of 51.2%. In Q-switching operation, the maximum average output power is 639 mW with a pulse width of 2.06 μs at a repetition frequency of 102.7 kHz.
APPLIED SCIENCES-BASEL
(2022)
Article
Optics
Elisa Riccardi, Valentino Pistore, Seonggil Kang, Lukas Seitner, Anna De Vetter, Christian Jirauschek, Juliette Mangeney, Lianhe Li, A. Giles Davies, Edmund H. Linfield, Andrea C. Ferrari, Sukhdeep S. Dhillon, Miriam S. Vitiello
Summary: By using multilayer graphene saturable absorbers, we have successfully demonstrated a self-starting miniaturized short pulse terahertz laser, which utilizes an original device architecture with surface patterning in the entire cavity of a double-metal semiconductor 2.30-3.55 THz wire laser. This compact, all-electronic, all-passive, and inexpensive configuration achieves self-starting pulsed emission with 4.0 ps-long pulses.
Article
Optics
Hao Sun, Zhipeng Qi, Youngmin Kim, Manlin Luo, Bo Yang, Donguk Nam
Summary: This study proposes the feasibility of creating graphene-based lasers at the chip scale, which can achieve wide-range tuning of output laser frequency, opening up new possibilities for graphene-based electronic-photonic integrated circuits.
Article
Energy & Fuels
Hugo Costa, Dawei Liang, Joana Almeida, Miguel Catela, Dario Garcia, Bruno D. Tiburcio, Claudia R. Vistas
Summary: A seven-rod solar laser head was designed and studied numerically, revealing that it can achieve highly stable solar laser emission and improve tracking error compensation capacity and power stability.
Article
Materials Science, Multidisciplinary
Yadi Wang, Masanobu Haraguchi, Xingbo Zhang, Pingping Wang, Shufeng Sun
Summary: A new method is proposed to enhance the optical confinement of a vertical cavity surface emitting laser (VCSEL) by introducing a square-lattice photonic crystal structure. The filling factor of this structure was optimized based on computation of the energy band structure and optical band values. By adjusting the length of the resonant cavity, a VCSEL with two wavelengths can be created without current injection. Numerical calculations show that incorporating a cubic photonic crystal structure in the VCSEL results in a 2x increase in the difference frequency intensity and a 6.33x increase in the optical field intensity.
Article
Physics, Applied
Zongyuan Wang, Bin Hu, Zhaoran Niu, Weiguang Liu, Guocui Wang, Yan Zhang
Summary: This study experimentally demonstrates that low-cost laser-induced porous graphene can support surface plasmon polaritons (SPPs) in the terahertz (THz) regime with good performance. A super-resolution focus was achieved using a classical structure of the semicircular slit in a THz-SPPs imaging system. The propagation loss of SPPs was found to be effectively controlled by changing the fabrication parameters of the laser. This controllable method for excited THz-SPPs on laser-induced porous graphene is of great significance for the design and wide-range applications of more compact THz on-chip devices.
APPLIED PHYSICS LETTERS
(2022)
Article
Materials Science, Multidisciplinary
Ritwik Mondal, Akashdeep Kamra
Summary: We investigate the spin pumping current injected by the nutation resonances of a ferromagnet (FM) or an antiferromagnet (AFM) into an adjacent metal. Comparing the dc spin pumping current between the normal precession and the nutation resonances, we find that the ratio of spin pumping current at the nutation resonance to the precession resonance is more pronounced in AFMs.
Article
Optics
Jingxuan Lan, Rongxuan Zhang, Hao Bai, Caidie Zhang, Xu Zhang, Wei Hu, Lei Wang, Yanqing Lu
Summary: In this study, a low-cost broadband tunable THz absorber based on one-step laser-induced graphene (LIG) was proposed, achieving over 90% absorption from 0.5 THz to 2 THz with optimized parameters.
CHINESE OPTICS LETTERS
(2022)
Article
Optics
J. I. A. N. Z. H. O. U. Huang, Bin Hu, G. U. O. C. U. Wang, Z. O. N. G. Y. U. A. N. Wang, J. I. N. L. O. N. G. LI, J. U. A. N. Liu, Y. A. N. Zhang
Summary: This work demonstrates a reconfigurable THz phase modulator with 5x5 independently tunable units enabled by switching the voltages applied on 10 graphene ribbons. The efficiency of the device is enhanced by 2.7-3.6 times under different graphene chemical potentials through introducing quasi bound states in the continuum resonance using a designed double C-shaped antenna. Experimental results show the formation of a focus with a changed focal length from 14.3mm to 22.6mm. This work provides potential for compact THz spatial light modulators that may be applied in THz communication, detection, and imaging.
PHOTONICS RESEARCH
(2023)
Article
Chemistry, Multidisciplinary
Shaohang Chen, Ruizhao Yang, Yanni Zhou, Binyi Qin, Yun Li, Jincun Zheng, Yizhi Liang, Tinghui Li, Jianming Liu
Summary: This study investigates the terahertz wave modulation properties of graphene using terahertz time-domain spectroscopy. The results show that graphene can modulate terahertz waves under different excitation laser powers.
Article
Chemistry, Physical
Zongyuan Wang, Guocui Wang, Bin Hu, Weiguang Liu, Jianzhou Huang, Chenjie Xiong, Yan Zhang, Juan Liu, Yongtian Wang
Summary: Terahertz technology has shown promising progress but faces challenges such as a lack of modulation materials and miniaturized system constraints. Laser-induced graphene has been discovered as a potential solution for THz wave modulation, offering a fast, large-area, and cost-effective manufacturing method.
Article
Optics
Hernan Ferrari, Victor Herrero, Carlos J. Zapata-Rodriguez, Mauro Cuevas
Summary: In this study, we investigated the optical force acting on a dielectric nanoparticle when located near a graphene monolayer in the terahertz spectrum. The graphene sheet on a dielectric substrate allowed the nano-sized scatterer to excite a well-confined surface plasmon. Large pulling forces can be exerted on the particle due to momentum conservation and self-action effect. The intensity of the pulling force depends critically on the shape and orientation of the particle. The low heat dissipation of graphene surface plasmons offers potential for the development of a novel plasmonic tweezer for biospecimen manipulation in the THz region.
Review
Nanoscience & Nanotechnology
Taiichi Otsuji, Stephane Albon Boubanga-Tombet, Akira Satou, Deepika Yadav, Hirokazu Fukidome, Takayuki Watanabe, Tetsuya Suemitsu, Alexander A. Dubinov, Vyacheslav V. Popov, Wojciech Knap, Valentin Kachorovskii, Koichi Narahara, Maxim Ryzhii, Vladimir Mitin, Michael S. Shur, Victor Ryzhii
Summary: This paper reviews recent advancements in graphene-based plasmonic metamaterials for terahertz (THz) laser transistors. The researchers investigate various approaches using graphene plasmonic metamaterials to achieve room-temperature, dry-cell-battery operated intense THz lasing with fast direct modulation. The paper discusses device structures and design constraints for coherent light sources applicable to future THz wireless communication systems.
Article
Physics, Condensed Matter
I. M. Moiseenko, V. V. Popov, D. Fateev
Summary: This study theoretically investigates the dispersion, excitation, and amplification of electromagnetic transverse electric (TE) modes at terahertz (THz) frequencies in graphene within the hydrodynamic regime. Researchers derived the expression for the nonlocal hydrodynamic conductivity of graphene in the presence of a direct electric current perpendicular to the TE mode wavevector. It was found that the capacitive nature of the graphene hydrodynamic conductivity at THz frequencies, induced by the direct electric current, supports the existence of TE modes in this frequency range. Additionally, a novel physical mechanism for the amplification of TE modes in graphene under a low carrier drift velocity was predicted, leading to the discovery of THz lasing regimes in the graphene structure with direct electric current.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2022)
Article
Optics
Yuma Takida, Kouji Nawata, Takashi Notake, Taiichi Otsuji, Hiroaki Minamide
Summary: A nonlinear optical mixing technique is used to detect and characterize sub-nanosecond terahertz (THz)-wave pulses. The frequency up-conversion and parametric amplification methods are employed for sensitive detection and intensity cross-correlation characterization. The experimental results reveal the temporal profile of THz-wave pulses generated by the injection-seeded THz-wave parametric generator (is-TPG) in the tunable range of 0.95-2.00 THz to have a pulse width of 150-190 ps at full width at half-maximum.
Article
Optics
D. S. Ponomarev, D. Lavrukhin, N. Zenchenko, T. Frolov, I. A. Glinskiy, R. A. Khabibullin, G. M. Katyba, V. N. Kurlov, T. Otsuji, K. Zaytsev
Summary: We present a sapphire-fiber-based lens that enhances the emitted THz power of a large-area photo-conductive antenna (PCA). Numerical simulations demonstrate the effectiveness of the lens in redistributing the photocarriers density in the PCA's gap. We also propose a step-by-step process to precisely and controllably place the sapphire-fiber on the surface of a single PCA.
Article
Nanoscience & Nanotechnology
Mikhail Yu. Morozov, Vyacheslav V. Popov, Denis Fateev
Summary: The study investigates the theoretical tuning of radiative damping in a periodic dual grating-gate graphene structure. By adjusting the applied dc voltage, the radiative damping of the weak plasmon mode can be changed, allowing for maximum energy conversion.
PHOTONICS AND NANOSTRUCTURES-FUNDAMENTALS AND APPLICATIONS
(2022)
Article
Physics, Applied
V. Ryzhii, T. Otsuji, M. Ryzhii, V. Mitin, M. S. Shur
Summary: This study demonstrates that resonant plasmonic detection significantly enhances the sensitivity of terahertz detectors based on a gated graphene field-effect transistor structure. By utilizing gated p and n regions as hole and electron reservoirs and terahertz resonant plasma cavities, the proposed device achieves terahertz signal rectification and excitation of plasmonic oscillations, leading to a substantial increase in detector responsivity.
PHYSICAL REVIEW APPLIED
(2022)
Article
Physics, Applied
V. Ryzhii, M. Ryzhii, V. Mitin, M. S. Shur, T. Otsuji
Summary: The Zener-Klein interband tunneling in graphene layers can be utilized for processing and generation of terahertz signals, with negative dynamic conductance and transit-time instability. By using periodic cascade structures, THz amplification and radiation can be achieved.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Optics
Dmitry S. Ponomarev, Denis Lavrukhin, Igor A. Glinskiy, Alexander E. Yachmenev, Nikolay Zenchenko, Rustam A. Khabibullin, Yurii G. Goncharov, Taiichi Otsuji, Kirill I. Zaytsev
Summary: This study proposes the design of a photoconductive antenna (PCA) emitter with a plasmonic grating featuring a very high plasmonic Au electrode with a thickness of 170 nm. Numerical simulations show that increasing h leads to the excitation of higher-order plasmon guided modes in the Au slit waveguides, resulting in an additional increase in the emitted THz power. The fabricated PCA demonstrates efficient operation with low-power laser excitation, achieving an overall THz power of 5.3 mu W over a bandwidth of approximately 4.0 THz, corresponding to a conversion efficiency of 0.2%. This design holds promise for modern THz spectroscopic and high-speed imaging applications.
Article
Multidisciplinary Sciences
Mikhail Yu Morozov, Vyacheslav V. Popov
Summary: We propose a concept of terahertz waveguide plasmon amplifier based on a metal groove with active graphene. It is shown that the power amplification factor of the LSM waveguide plasmon near the cut-off frequency of this mode can exceed the amplification factor of the TM plasmon in a layered graphene structure by more than four orders of magnitude for the same frequency. This is caused by the increase of the LSM plasmon wavelength near the cut-off frequency, smaller energy velocity of the LSM mode, and greater energy release from graphene for the LSM plasmon due to stronger lateral confinement of the LSM waveguide plasmon as compared to the TM plasmon in a layered graphene structure.
SCIENTIFIC REPORTS
(2022)
Article
Optics
Koichi Tamura, Chao Tang, Daichi Ogiura, Kento Suwa, Hirokazu Fukidome, Yuma Takida, Hiroaki Minamide, Tetsuya Suemitsu, Taiichi Otsuji, Akira Satou
Summary: In this study, a new epitaxial graphene field-effect transistor with an asymmetric dual-grating-gate (ADGG) structure was designed and fabricated to achieve fast and sensitive detection of terahertz radiation. The experimental results demonstrated its promising performance in high-speed wireless communication systems.
Article
Physics, Applied
V. Ryzhii, C. Tang, T. Otsuji, M. Ryzhii, V. Mitin, M. S. Shur
Summary: We evaluated THz detectors based on graphene channel (GC) and a floating metal gate (MG) separated from GC by a black-phosphorus (b-P) or black-arsenic (b-As) barrier layer (BL). The operation of these GC-FETs involves heating of the two-dimensional electron gas in GC by THz radiation, leading to thermionic emission of hot electrons from GC to MG. This results in variation of the floating gate potential, affecting the source-drain current. At THz radiation frequencies close to plasmonic resonance frequencies in the gated GC, the variation in source-drain current and detector responsivity can be resonantly large.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Physics, Condensed Matter
I. M. Moiseenko, V. V. Popov, D. Fateev
Summary: For the first time, we investigate the interaction between the waveguide modes of a graphene structure and freely propagating terahertz electromagnetic waves. We discover a new physical phenomenon where incident THz waves can resonate with the surface TE modes of the graphene waveguide due to their dispersions near the light cone. We study the dispersion, amplification, and lasing of the surface TE modes in a dielectric waveguide covered with biased graphene layers, as well as the amplification and lasing of THz waves through TE mode resonances.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2023)
Article
Chemistry, Multidisciplinary
Omnia Samy, Mohamed Belmoubarik, Taiichi Otsuji, Amine El Moutaouakil
Summary: This study presents a thin THz absorber that can be easily tuned through the whole THz range (0.1-10 THz) by applying a low gate voltage (<1 V). The structure is based on cheap and abundant materials (MoS2/graphene). The absorptance frequency and width can be controlled by varying the structure and substrate dimensions, making it a promising alternative to expensive THz metamaterial-based absorbers.
Article
Nanoscience & Nanotechnology
V. Ryzhii, C. Tang, T. Otsuji, M. Ryzhii, S. G. Kalenkov, V. Mitin, M. S. Shur
Summary: In this study, we investigate the response of the micromechanical field-effect transistors (MMFETs) to terahertz (THz) signals. The MMFET utilizes microcantilevers (MC) as a floating gate and the movable mirror of Michelson optical interferometer. The mechanical vibrations of MC are converted into optical signals, allowing MMFET to operate as a THz radiation detector. The combination of mechanical and plasmonic resonances in MMFET, along with optical amplification, enables effective THz detection.
Article
Nanoscience & Nanotechnology
Juan A. Delgado-Notario, Wojciech Knap, Vito Clerico, Juan Salvador-Sanchez, Jaime Calvo-Gallego, Takashi Taniguchi, Kenji Watanabe, Taiichi Otsuji, Vyacheslav V. Popov, Denis V. Fateev, Enrique Diez, Jesus E. Velazquez-Perez, Yahya M. Meziani
Summary: This study fabricated a graphene terahertz field-effect transistor with an asymmetric-dual-grating-gate and a continuous graphite back-gate, which enhanced the THz rectified signal by forming abrupt junctions with different potential barriers. This paves the way for new record performances of graphene THz nano-photodetectors.
