Editorial Material
Nanoscience & Nanotechnology
Miriam S. Vitiello, Luigi Consolino, Massimo Inguscio, Paolo De Natale
Summary: QCL is the most powerful chip-scale source of optical frequency combs, allowing mode proliferation with large quantum efficiencies. THz QCL FCs have promising applications in various fields due to their high quantum efficiency and ease of integration.
Article
Physics, Applied
Li Wang, Tsung-Tse Lin, Mingxi Chen, Ke Wang, Hideki Hirayama
Summary: This study demonstrates the crucial role of compositional interdiffusion at interfaces in GaAs/AlGaAs alternating superlattices for developing high temperature terahertz quantum cascade lasers. By growing GaAs/Al0.3Ga0.7As superlattices using molecular beam epitaxy, an aluminum interdiffusion width of 0.95 nm is estimated. Incorporating this interdiffusion as a design parameter improves the maximum operating temperature of the laser by 20 K. The study also introduces an independent self-energy function based on axial correlation length to quantify the effects of interdiffusion scattering on electron dynamics.
APPLIED PHYSICS EXPRESS
(2023)
Article
Optics
Yuan-Yuan Li, Fang-Yuan Zhao, Yu Ma, Wei-Jiang Li, Jun-Qi Liu, Feng-Qi Liu, Jun-Wei Luo, Jin-Chuan Zhang, Shen-Qiang Zhai, Ning Zhuo, Li-Jun Wang, Shu-Man Liu
Summary: By integrating a suitable lens with a well-designed QCL array, multiple spatially-separated beams with controlled divergence angles and focusing efficiency are achieved. This method demonstrates excellent emission characteristics and multi-wavelength spectra at 77 K temperature.
OPTICS AND LASER TECHNOLOGY
(2021)
Article
Physics, Applied
M. Jaidl, N. Opacak, M. A. Kainz, D. Theiner, B. Limbacher, M. Beiser, M. Giparakis, A. M. Andrews, G. Strasser, B. Schwarz, J. Darmo, K. Unterrainer
Summary: This paper demonstrates terahertz quantum cascade lasers realized in ideal ring resonators without discontinuities, achieved by mounting the rings upside down on a silicon substrate using a die-bonding technique. The lasers emit light around 3.8 THz, show reduced threshold current densities, and exhibit frequency comb formation.
APPLIED PHYSICS LETTERS
(2022)
Article
Physics, Applied
Sergej Markmann, David Stark, Matthew Singleton, Mattias Beck, Giacomo Scalari
Summary: In this work, we measure the electric field of a free-running terahertz QCL frequency comb using electro-optic sampling and computational phase correction. This method is important for characterizing the time-resolved emission of low-power laser and investigating phase-compensated emission for broadband comb operation.
PHYSICAL REVIEW APPLIED
(2023)
Article
Optics
Yunfei Xu, Yongqiang Sun, Weijiang LI, Yu Ma, Ning Zhuo, Junqi Liu, Jinchuan Zhang, Shenqiang Zhai, Shuman Liu, Lijun Wang, Fengqi Liu
Summary: This article reports on a phase-locked array scheme of terahertz quantum cascade laser (THz QCL) that utilizes Talbot effect. By adjusting the absorbing boundary width of each ridge in the array, stable operation and power amplification of THz QCL are achieved.
Review
Quantum Science & Technology
Miriam Serena Vitiello, Paolo De Natale
Summary: Quantum cascade lasers (QCLs) demonstrate the generation of artificial materials with tailor-made properties through quantum design, featuring intrinsic linewidths near the quantum limit and spontaneous phase-locking. Operating at terahertz frequencies, QCLs show important technological performances and have promising future prospects in the field of quantum technologies.
ADVANCED QUANTUM TECHNOLOGIES
(2022)
Article
Physics, Multidisciplinary
Mohammad Reza Kazemi-Tesieh, Hossein Reza Yousefvand, Abbas Ghadimi, Azadeh Kiani-Sarkaleh
Summary: This paper investigates the feasibility of inversionless terahertz (THz) lasing in a mid-infrared (mid-IR) quantum cascade laser (QCL) using the density matrix formalism. The proposed structure integrates a mid-IR QCL as a pump source with a four-level Raman-type scheme to generate THz radiation through strong coherence excited in the system. The interplay between inversion-based lasing and coherent effects in the four-level system leads to THz intensity gain derived from the off-diagonal density matrix elements.
Article
Physics, Applied
Tsung-Tse Lin, Li Wang, Ke Wang, Thomas Grange, Stefan Birner, Teppei Miyoshi, Hideki Hirayama
Summary: By implementing a relatively high impurity doping concentration, the output power of a GaAs-based terahertz quantum cascade laser was significantly enhanced.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Optics
Boyu Wen, Dayan Ban
Summary: This study proposes a potential and promising new quantum design scheme named the quasi one-well (Q1W) design for developing high-temperature terahertz quantum cascade lasers (QCLs). Simulation results using non-equilibrium green function and rate-equation models suggest that the Q1W design has the potential to achieve sufficient optical gain with low-temperature sensitivity.
Article
Optics
Ali Khalatpour, Andrew K. Paulsen, Chris Deimert, Zbig R. Wasilewski, Qing Hu
Summary: Terahertz frequencies are underutilized due to the lack of powerful and compact sources, but the invention of THz quantum cascade lasers has helped bridge this gap and expand potential applications. However, the technology is still limited by demanding cooling requirements, restricting its practical use outside of laboratory settings.
Article
Chemistry, Multidisciplinary
Qi Yang, Jicheng Zhang, Xuemin Wang, Zhiqiang Zhan, Tao Jiang, Jia Li, Ruijiao Zou, Keyu Li, Fengwei Chen, Weidong Wu
Summary: This work presents a dual ridge terahertz quantum cascade laser lasing at 3.1 THz and analyzes its performance in detail. The experimental results provide a reference for realizing high-power terahertz quantum cascade lasers and offer guidance for the structural design of multiple ridges or laser arrays.
Article
Optics
Muhammad Anisuzzaman Talukder, Paul Dean, Edmund H. Linfield, A. Giles Davies
Summary: This study introduces a THz QCL heterostructure designed to emit two resonant photons from each electronic relaxation between two same-parity states, predicting a significant enhancement of light intensity compared to conventional THz QCL structures through simulations.
Article
Multidisciplinary Sciences
Li Wang, Tsung-Tse Lin, Ke Wang, Hideki Hirayama
Summary: This study investigates the impact of high-energy lying non-relevant subbands on terahertz quantum cascade lasers at high temperatures. The findings reveal that these subbands have a minor effect on electron inversion but play a major role in optical gain. This phenomenon is attributed to the presence of leakages caused by sequential resonant tunneling, influenced by the specific features of the design involving phonon wells and periodic length.
SCIENTIFIC REPORTS
(2022)
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
Physics, Applied
Attique Dawood, SaeJune Park, Rowan Parker-Jervis, Chris Wood, Lianhe H. Li, Edmund H. Linfield, Alexander Giles Davies, John Cunningham, Oleksiy Sydoruk
Summary: We demonstrate the engineering of low-terahertz range plasmonic spectra in two-dimensional electron systems by modifying their geometry. By comparing the results of two devices, one with a rectangular channel and the other with a trapezoidal channel, we show the different characteristics of each device. This research highlights the potential of modifying the channel geometry to obtain different spectra in experiments and has important implications for the design of novel terahertz-range devices.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2022)
Article
Physics, Multidisciplinary
Aleksandar Demic, Zoran Ikonic, Paul Dean, Dragan Indjin
Summary: This work discusses terahertz quantum cascade laser designs that utilize resonant phonon mechanism for assisting the lasing process. The study investigates whether higher energy separation would be more beneficial for high temperature performance compared to the commonly used resonant value. A density matrix model is employed for reliable cut-off temperature estimation, and design improvements are presented to enhance material gain and achieve 10-50 K higher cut-off temperature.
NEW JOURNAL OF PHYSICS
(2022)
Article
Engineering, Electrical & Electronic
Suraj P. Khanna, Satish Singh, C. K. Suman, Nandan Kumar
Summary: The write-once-read-many (WORM) memory effect is reported in a polyethylene terephthalate (PET)-metal fiber spun electroconductive yarn with a tex of 19.68 and a ratio of 80:20. The yarn sample exhibits typical WORM memory behavior with a high OFF/ON resistance ratio and long retention period. The charge conduction mechanism changes from electronic to ionic as the polyester fibers undergo phase transition. Additionally, the sample can be reset to its initial high-resistive state through intentional mechanical perturbation.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
News Item
Physics, Multidisciplinary
Julien Madeo, Keshav M. Dani
Summary: Quantum confinement effects provide a more comprehensive understanding of extreme optical nonlinearities in nano-engineered solids, offering a pathway to unlock the potential of high-order harmonic generation.
Article
Optics
Muhammad Anisuzzaman Talukder, Paul Dean, Edmund H. Linfield, A. Giles Davies
Summary: This study introduces a THz QCL heterostructure designed to emit two resonant photons from each electronic relaxation between two same-parity states, predicting a significant enhancement of light intensity compared to conventional THz QCL structures through simulations.
Article
Multidisciplinary Sciences
Eric Kumi Barimah, Artitsupa Boontan, David P. Steenson, Gin Jose
Summary: Vanadium dioxide (VO2(M1)) is a thermochromic material that has been widely used for energy efficiency and indoor comfort in buildings. A direct method to fabricate pure VO2(M1) thin films onto hot silica substrates using femtosecond laser deposition is presented. The study investigates the structural and optical properties of the thin films as a function of substrate temperature.
SCIENTIFIC REPORTS
(2022)
Article
Engineering, Electrical & Electronic
Eleanor Nuttall, Yingjun Han, Diego Pardo, Sanchit S. Kondawar, Nick Brewster, Mohammed Salih, Lianhe Li, Michael D. Horbury, A. Giles Davies, Edmund H. Linfield, Hui Wang, Paul Dean, Brian N. Ellison, Alexander Valavanis
Summary: Waveguide integration of terahertz quantum cascade lasers (THz QCLs) is achieved above 4.7 THz frequencies. A fabrication method involving precision micromachining, diamond-turning, and electroless-plating is utilized to manufacture hollow rectangular waveguides with diagonal feedhorns integrated. The surface roughness at the level of approximately 1 μm is attained, allowing radiation outcoupling in the 4.75-5.05 THz band with a divergence angle less than 5 degrees along the QCLs substrate plane.
ELECTRONICS LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Suraj P. Khanna, Satish Singh, C. K. Suman, Nandan Kumar, Alok Dabi
Summary: Multilevel non-volatile resistive switching behavior is observed in electronic textile, displaying write-once-read-many (WORM) memory behavior and allowing conduction modulation using a remote current-bias write/input stimulus. Anisotropic current spreading in the textile can be utilized for selective memory writing and emulating neuron-like behavior. The textile also exhibits the reset WORM or ReWORM effect.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Nanoscience & Nanotechnology
Laurent Boulley, Thomas Maroutian, Paul Goulain, Andrey Babichev, Anton Egorov, Lianhe Li, Edmund Linfield, Raffaele Colombelli, Adel Bousseksou
Summary: We demonstrate low temperature deposition conditions for VO2 phase change material that are compatible with III-V semiconductors used in optoelectronic applications. The VO2 coated thin films grown on GaAs exhibit a 50% change in optical reflectivity and a significant variation in electric conductivity between insulating and metallic states. We also study the functionalization of mid-infrared QCLs with VO2 layers to engineer their laser emission properties.
Article
Physics, Applied
C. Song, M. Salih, L. H. Li, J. Mangeney, J. Tignon, A. G. Davies, E. H. Linfield, S. Dhillon
Summary: By using thin metallic side-absorbers, researchers have successfully suppressed higher-order transverse modes in Terahertz quantum cascade lasers (THz QCLs), allowing the lasers to operate solely on the fundamental transverse mode without sacrificing high power outputs. This breakthrough opens up opportunities for investigating nonlinear THz physical phenomena using THz QCLs as pump sources.
APPLIED PHYSICS LETTERS
(2023)
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
Chemistry, Analytical
Khushboo Singh, Aparajita Bandyopadhyay, Karl Bertling, Yah Leng Lim, Tim Gillespie, Dragan Indjin, Lianhe Li, Edmund H. Linfield, A. Giles Davies, Paul Dean, Aleksandar D. Rakic, Amartya Sengupta
Summary: In order to reduce water consumption in agriculture, photonics-based hydration sensing technology has been widely used for non-contact, non-invasive mapping of liquid water in plants. In this study, terahertz (THz) range sensing techniques were employed to map liquid water in leaves of Bambusa vulgaris and Celtis sinensis. Two complementary techniques, THz time-domain spectroscopic imaging and THz quantum cascade laser-based imaging, were utilized. The results provide detailed spatial and temporal information about hydration dynamics and dehydration effects on leaf structure.
Article
Materials Science, Multidisciplinary
Craig S. Knox, Matthew T. Vaughan, Andrew D. Burnett, Mannan Ali, Satoshi Sasaki, Edmund H. Linfield, Alexander Giles Davies, Joshua R. Freeman
Summary: In this study, we investigated the properties of THz conductivity spectra in the ternary alloy Bi2(Te(1-x)Sex)3 as a function of selenium fraction, x, and temperature. Our findings suggest that preferential ordering in the x = 1/3 phase of Bi2(Te(1-x)Sex)3 leads to a red-shift in the Eu1 phonon on cooling, compared to binary Bi2Te3 and Bi2Se3 samples. We also observed coupling between the Eu1 phonon and an electronic continuum at low temperatures, regardless of the alloy's stoichiometry or the Hall mobility of the topological insulator crystal. These results highlight the importance of these optical modes in the transport properties of this ternary alloy.
Article
Materials Science, Multidisciplinary
A. Beckert, M. Grimm, R. Hermans, J. R. Freeman, E. H. Linfield, A. G. Davies, M. Muller, H. Sigg, S. Gerber, G. Matmon, G. Aeppli
Summary: The crystal field energy levels and magnetic moments of the insulating rare-earth magnet LiY1-xHoxF4 were investigated, including the hyperfine corrections, and the far-infrared, low-temperature refractive index of the material was determined.
