Article
Engineering, Electrical & Electronic
Honggang Sun, Lixin Wang, Jinhai Zou, Qiujun Ruan, Yu Ding, Chuchu Dong, Zhipeng Dong, Zhengqian Luo
Summary: We report the first visible-wavelength all-fiber passively mode-locked vortex laser, capable of delivering picosecond optical vortex pulses with adjustable pulse duration and narrow linewidth. This study also demonstrates the potential applications of this technology in particle trapping, optical tweezers, and high-resolution microscopy.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2022)
Article
Multidisciplinary Sciences
KyeoReh Lee, Ho Jin Ma, Fabian Rotermund, Do Kyung Kim, YongKeun Park
Summary: Non-resonant lasers have the potential for stable and consistent narrowband light sources, but their practical applications are limited by low power efficiency and omnidirectional emission. A proposed light trap design based on a spherical scattering cavity aims to improve its efficiency and directionality.
NATURE COMMUNICATIONS
(2021)
Article
Engineering, Electrical & Electronic
Jingtong Geng, Liu Yang, Yonggang Zhang
Summary: A novel resonant optical gyroscope (ROG) based on all-optical frequency locking method has been proposed, utilizing a small-size, low-power, and low-cost semiconductor laser to simplify the locking mechanism. It achieves high-precision frequency measurement and shows potential to be a high-precision and integration angular velocity sensor.
IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT
(2022)
Article
Physics, Applied
Ting Wang, Jiliang Wu, Yuede Yang, Jinlong Xiao, Yongzhen Huang
Summary: This article presents a highly coherent optical frequency comb (OFC) technology based on the spectral broadening of a phase-locked dual-wavelength microcavity laser. By directly modulating the microcavity laser to generate multiple sidebands, the cross-injection locking of the dual modes is achieved, resulting in an improved beat-signal linewidth from 13.5 MHz to less than 100 Hz. Subsequently, 21 flat comb teeth in a +/- 3 dB power variation are achieved by combining a phase modulator. Finally, an OFC with a bandwidth of 16 nm is successfully realized by narrowing the optical pulse and spectral broadening in a commercial nonlinear optical fiber. The repetition rate has a low phase noise of -102 dBc Hz(-1) at 10 kHz offset, demonstrating the generated OFC has a high degree of coherence.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2023)
Article
Chemistry, Analytical
Gi Hyen Lee, Soyeon Ahn, Jinhwa Gene, Min Yong Jeon
Summary: The study presented a wideband wavelength-swept laser utilizing two semiconductor optical amplifiers and a polygonal scanning wavelength filter. It showed that the bandwidth of the laser decreased and the intensity dropped as the scanning speed increased. Additionally, dynamic changes in the reflection of a cholesteric liquid crystal cell in the 1-micrometer band were observed.
Article
Engineering, Electrical & Electronic
Shun Matsuo, Hiroyuki Uenohara
Summary: This study investigates all-optical wavelength conversion based on four-wave mixing in highly nonlinear fiber using pump lights generated from optical combs and SSB modulation. It achieves wide wavelength selectivity and highly precise frequency controllability. The experimental results show that the use of generated pump lights for FWM leads to clear constellations and low bit error rates.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2022)
Article
Chemistry, Multidisciplinary
Xiaolong Zhu, Jacob Engelberg, Sergei Remennik, Binbin Zhou, Jonas Nyvold Pedersen, Peter Uhd Jepsen, Uriel Levy, Anders Kristensen
Summary: This work presents a cost-effective and lithography-free method for printing optical metasurfaces. By utilizing resonant absorption of laser light in an optical cavity formed by a multilayer structure, nearly perfect light absorption is achieved through interferometric control. This approach demonstrates reliability, upscaling, and subwavelength resolution in creating metasurfaces for structural colors, optical holograms, and diffractive optical elements.
Article
Optics
Shiran Levy, Nathalie Lander Gower, Silvia Piperno, Sadhvikas J. Addamane, John L. Reno, Asaf Albo
Summary: We propose a highly diagonal split-well resonant-phonon (SWRP) active region design for GaAs/Al0.3Ga0.7As terahertz quantum cascade lasers (THz-QCLs). The design successfully suppresses thermally activated leakage channels, as evidenced by the observation of negative differential resistance at room temperature. The reduced overlap between the doped region and the active level states improves the performance of the laser.
Article
Optics
Chunxia Hu, Guangqiong Xia, Dianzuo Yue, Zaifu Jiang, Bing Cui, Yanfei Zheng, Gongru Lin, Zhengmao Wu
Summary: A chaotic communication system with switchable chaotic carrier wavelength is proposed and demonstrated using weak-resonant-cavity Fabry-Perot laser diodes. The system achieves high-quality chaotic synchronization and successful decryption of encrypted messages at the receiver. Experimental results show promising performance in terms of correlation coefficients and bit error ratios.
Article
Engineering, Electrical & Electronic
Keiji Kuroda, Ui Inaba
Summary: The dual-wavelength differential detection technique of fiber Bragg gratings is described in this study. A directly modulated distributed-feedback laser array is used as a frequency-scanning pulsed light source. By measuring two serially connected Bragg gratings using the pulse trains, the selectivity of high-sensitivity measurement, wide measurement range, and the potential for expansion to time-division multiplexing systems are demonstrated.
IEEE PHOTONICS TECHNOLOGY LETTERS
(2022)
Article
Optics
Qusay M. A. Hassan, H. A. Sultan, Hussein F. Hussein, C. A. Emshary
Summary: The objective of this study is to find a material with high nonlinear optical properties and test its optical limiting and all-optical switching properties. The nonlinear refractive index of the material is determined using two techniques, and theoretical calculations are performed on the far-field diffraction patterns.
Article
Engineering, Electrical & Electronic
Yamato Misugi, Hideaki Okayama, Tomohiro Kita
Summary: In this study, a passive beam scanner was proposed to achieve two-dimensional beam scanning through wavelength sweep of a laser light. A 64-channel passive optical phased array and a hybrid wavelength-tunable laser diode were integrated into a combined chip, with a device size of 5mm x 1.5mm and power consumption of 49.3 mW. Compared with previous devices, it was nine times smaller in size and had a total power consumption of only tens of milliwatts. This device has lower power consumption and achieves fully integrated light detection and ranging.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
Keiji Kuroda
Summary: This study reports the wavelength-division multiplexed interrogation of fiber Bragg gratings using a directly modulated distributed-feedback laser array as a multi-wavelength, frequency scanning, pulsed-light source. The heterodyne detection technique is employed to increase the signal-to-noise ratio of weak reflection signals. Reflections from three fiber Bragg gratings with different peak wavelengths are simultaneously observed as beat oscillations, with clear reflection spectra visible at a signal-to-noise ratio of approximately 20 dB.
IEEE PHOTONICS TECHNOLOGY LETTERS
(2022)
Article
Engineering, Electrical & Electronic
Mengmeng Chai, Lijun Qiao, Shuhui Li, Xiaojing Wei, Hongchun Xu, Jie Zhao, Mingjiang Zhang
Summary: This study presents the development of a wavelength-tunable chaotic semiconductor laser chip, capable of adjusting wavelength and fine-tuning central wavelength by current adjustment. The transition from periodic oscillation to chaotic oscillation, as well as the dynamics and bandwidth variations induced by current, are investigated.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2022)
Article
Optics
Jiazhu Wang, Xiaohui Li, Liang Jin, Renyan Wang, Shangzhi Xie, Tiebin Wang, He Zhang, Yingtian Xu, Yan Li, Xiaohui Ma
Summary: In this paper, an all-fiber single- and dual-wavelength tunable CVBs fiber laser using the nonlinear optical saturation absorption characteristics and filtering properties of nonlinear multimode interference (NL-MMI) is reported for the first time. The experiment demonstrated the ability to tune the central wavelength of the mode-locked CVBs fiber laser in both single- and dual-wavelength configurations. This NL-MMI-based wavelength-tunable ultrashort pulse CVBs fiber laser has great potential in optical communication.
OPTICS AND LASER TECHNOLOGY
(2023)
Article
Chemistry, Multidisciplinary
Alessandra Di Gaspare, Valentino Pistore, Elisa Riccardi, Eva A. A. Pogna, Harvey E. Beere, David A. Ritchie, Lianhe Li, Alexander Giles Davies, Edmund H. Linfield, Andrea C. Ferrari, Miriam S. Vitiello
Summary: This study demonstrates mode-locking in surface-emitting electrically pumped random quantum cascade lasers at terahertz frequencies by exploiting the giant third-order nonlinearity of semiconductor heterostructure lasers and the nonlinear properties of graphene. Self-induced phase-coherence between naturally incoherent random modes and phase-locked random modes are achieved using lithographically patterning a multilayer graphene film or coupling a saturable absorber graphene reflector. This milestone in the physics of disordered systems paves the way for miniaturized, electrically pumped mode-locked light sources for various applications.
Article
Chemistry, Multidisciplinary
Leonardo Viti, Elisa Riccardi, Harvey E. Beere, David A. Ritchie, Miriam S. Vitiello
Summary: The on-chip integration of two-dimensional nanomaterials with terahertz quantum cascade lasers has led to wide spectral tuning, nonlinear high-harmonic generation, and pulse generation. In this study, a large area multilayer graphene (MLG) was transferred to a THz QCL to monitor its local lattice temperature during operation. The MLG's temperature dependence of electrical resistance was used to measure the local heating of the QCL chip. The results were validated through photoluminescence experiments. This integrated system provides a fast temperature sensor for THz QCLs and enables full electrical and thermal control on laser operation.
Letter
Chemistry, Multidisciplinary
Daisy Q. Wang, Zeb Krix, Oleg P. Sushkov, Ian Farrer, David A. . Ritchie, Alexander R. . Hamilton, Oleh Klochan
Summary: By imposing an external periodic electrostatic potential, the electronic properties of the confined electrons in a quantum well can be different from those in the host semiconductor. In this study, we fabricated and investigated a tunable triangular artificial lattice on a GaAs/AlGaAs heterostructure, where the band structure and Fermi surface can be transformed by altering a gate bias. Magnetotransport measurements revealed multiple quantum oscillations and commensurability oscillations due to electron scattering from the artificial lattice. Increasing the modulation strength revealed new commensurability oscillations caused by electron scattering from the artificial Fermi surface and triangular lattice. These results demonstrate the ability to form artificial two-dimensional crystals with designer electronic properties using low disorder gate-tunable lateral superlattices.
Article
Nanoscience & Nanotechnology
J. D. Fletcher, W. Park, S. Ryu, P. See, J. P. Griffiths, G. A. C. Jones, I. Farrer, D. A. Ritchie, H. -s. Sim, M. Kataoka
Summary: Coulomb forces between high-energy electrons in unscreened regime are detected and analysed using a mesoscopic electron collider. The ability to control Coulomb interactions on picosecond time scales is crucial for quantum logic devices with flying electrons. Despite previous findings, our study reveals Coulomb-dominated collisions of high-energy single electrons in counter-propagating ballistic edge states, indicating new ways to utilize Coulomb interactions for high-speed sensing or gate operations on flying electron qubits.
NATURE NANOTECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
C. P. Dobney, A. Nasir, P. See, C. J. B. Ford, J. P. Griffiths, C. Chen, D. A. Ritchie, M. Kataoka
Summary: We have fabricated a device with two lateral p-n junctions on an n-type GaAs/Al0.33Ga0.67As heterostructure. The n-type material was converted to p-type by removing dopants and applying a voltage to a gate in this region. Controlled electroluminescence from both p-n junctions was demonstrated by varying the applied bias voltages. The emitted spectrum peak width was approximately 8 units.
SEMICONDUCTOR SCIENCE AND TECHNOLOGY
(2023)
Article
Physics, Applied
L. Liu, Y. Gul, S. N. Holmes, C. Chen, I. Farrer, D. A. Ritchie, M. Pepper
Summary: In this study, we systematically investigate a structure found in In0.75Ga0.25As heterostructures, and observe its stability and anisotropy in high magnetic fields. This research is important for understanding low-dimensional electronic systems with strong spin-orbit coupling.
APPLIED PHYSICS LETTERS
(2023)
Article
Nanoscience & Nanotechnology
Abdullah M. Zaman, Yuezhen Lu, Nikita W. Almond, Oliver J. Burton, Jack Alexander-Webber, Stephan Hofmann, Thomas Mitchell, Jonathan D. P. Griffiths, Harvey E. Beere, David A. Ritchie, Riccardo Degl'Innocenti
Summary: The study investigates the polarization modulation performance of an integrated metamaterial/graphene device in the THz band. By modifying the graphene's Fermi level, the device's optical response can be modified, enabling active tuning of ellipticity and continuous modification of optical activity. Active circular dichroism and optical activity can be independently exploited by carefully selecting the transmitted frequency and relative angle between the incoming linear polarization and the device's symmetry axis. This all-electronically tuneable versatile polarization device has potential applications in polarization spectroscopy, imaging, and THz wireless generation.
FRONTIERS IN NANOTECHNOLOGY
(2023)
Article
Materials Science, Multidisciplinary
P. M. T. Vianez, Y. Jin, W. K. Tan, Q. Liu, J. P. Griffiths, I. Farrer, D. A. Ritchie, O. Tsyplyatyev, C. J. B. Ford
Summary: Determining the bare electron mass (m0) in crystals is challenging due to many-body effects. By using a one-dimensional geometry, the interaction effects can be separated from m0, and the measured value is (0.0525 +/- 0.0015)me in GaAs. The value of m0 remains constant with varying density, and it is approximately 22% lighter than observed in higher-dimensional GaAs structures, consistent with the quasiparticle picture of a Fermi liquid.
Article
Materials Science, Multidisciplinary
M. J. Rendell, S. D. Liles, A. Srinivasan, O. Klochan, I. Farrer, D. A. Ritchie, A. R. Hamilton
Summary: In two-dimensional systems with a spin-orbit interaction, magnetic focusing is utilized to separate particles with different spins spatially. We conducted measurements on hole magnetic focusing under two different magnitudes of the Rashba spin-orbit interaction. We discovered that the attenuation of a focusing peak, conventionally linked to a change in spin polarization, is actually caused by a change in the scattering of a spin state in hole systems with a k3 spin-orbit interaction. Additionally, we found that the change in scattering length determined through magnetic focusing is consistent with the results obtained from Shubnikov-de Haas oscillations measurements.
Proceedings Paper
Engineering, Electrical & Electronic
J. Holstein, M. Horbury, N. North, H. Godden, A. Krysl, A. Lisauskas, L. H. Li, A. Valavanis, J. R. Freeman, E. H. Linfield, H. G. Roskosl
Summary: Researchers propose a new design for a terahertz detector, using a matrix of 8x8 monolithically integrated patch-antenna-coupled TeraFETs as the pixels and combining the output signals of all elements in a parallel read-out circuit. This design offers a larger effective detector area, easier beam alignment, and reduced resistance, leading to reduced noise and improved time resolution in measurements of dynamic processes.
2023 48TH INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER, AND TERAHERTZ WAVES, IRMMW-THZ
(2023)
Proceedings Paper
Engineering, Electrical & Electronic
M. D. Horbury, N. K. North, J. Holstein, H. Godden, L. H. Li, J. R. Freeman, E. H. Linfield, H. Roskos, A. Lisauskas, A. Valavanis
Summary: Here, we have demonstrated the potential of using terahertz (THz) spectroscopy to probe chemical reactions by observing distinct transitions in methanol and deuterated methanol (CH3OD) in specific THz frequency regions.
2023 48TH INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER, AND TERAHERTZ WAVES, IRMMW-THZ
(2023)
Proceedings Paper
Engineering, Electrical & Electronic
C. Kidd, M. C. Rosamond, T. B. Gill, L. H. Li, E. H. Linfield, A. G. Davies, J. R. Freeman
Summary: An improved large area design has been developed for LT-GaAs photoconductive antenna arrays on sapphire substrates, resulting in higher field terahertz radiation.
2023 48TH INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER, AND TERAHERTZ WAVES, IRMMW-THZ
(2023)
Proceedings Paper
Engineering, Electrical & Electronic
N. K. North, J. Holstein, M. D. Horbury, H. Godden, L. H. Li, J. R. Freeman, E. H. Linfield, H. Roskos, A. Lisauskas, A. Valavanis
Summary: This study demonstrates real-time analysis of the emission from a 3.4-THz quantum-cascade laser using an array of nanoscale field-effect transistor devices. The results show that THz power can be directly detected up to a modulation bandwidth of 500 kHz, and indirectly through a change in the device threshold up to a bandwidth of 100 MHz.
2023 48TH INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER, AND TERAHERTZ WAVES, IRMMW-THZ
(2023)
Proceedings Paper
Engineering, Electrical & Electronic
M. Salih, S. S. Kondawar, N. Brewster, L. H. Li, E. H. Linfield, H. Wang, P. G. Huggard, J. R. Freeman, D. Gerber, A. Valavanis
Summary: This study demonstrates the integration of a 2.1-THz quantum cascade laser into an IEEE standard rectangular metallic waveguide for the first time, resulting in single-mode continuous-wave laser emission.
2023 48TH INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER, AND TERAHERTZ WAVES, IRMMW-THZ
(2023)
Proceedings Paper
Engineering, Electrical & Electronic
T. B. Gill, A. D. Burnett, C. Towler, C. Kidd, A. Dunn, L. Li, J. R. Freeman, E. H. Linfieldl, A. G. Davies, P. Dean
Summary: High field terahertz spectroscopy measurements demonstrate that the features of lactose monohydrate at certain frequencies saturate with increasing THz field strength, indicating the potential of dynamically distorting the crystal structure at sufficiently high fields.
2023 48TH INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER, AND TERAHERTZ WAVES, IRMMW-THZ
(2023)