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
Nanoscience & Nanotechnology
Alessandra Di Gaspare, Leonardo Viti, Harvey E. Beere, David D. Ritchie, Miriam S. Vitiello
Summary: This paper reports a homogeneous quantum cascade laser operating at terahertz frequencies, with high power and stability, serving as an optical frequency comb synthesizer. Experimental results demonstrate the advantages of this laser, including high power levels and stable operation characteristics.
Article
Physics, Applied
Ali Khalatpour, Man Chun Tam, Sadhvikas J. Addamane, John Reno, Zbignew Wasilewski, Qing Hu
Summary: In this paper, the maximum operating temperature of THz QCLs has been improved to approximately 261K, as a step toward the realization of compact semiconductor THz sources.
APPLIED PHYSICS LETTERS
(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
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
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
Nanoscience & Nanotechnology
Kimberly S. Reichel, Eva Arianna Aurelia Pogna, Simone Biasco, Leonardo Viti, Alessandra Di Gaspare, Harvey E. Beere, David A. Ritchie, Miriam S. Vitiello
Summary: This study demonstrates the use of electrically pumped random laser resonators as sensitive photodetectors through the self-mixing effect, and shows the laser sensitivity to self-mixing under different feedback conditions. By utilizing two-dimensional cavities and reflecting emitted light back onto the surface, a near-field optical microscope with 120 nm spatial resolution is achieved, opening up possibilities for speckle-free nano-imaging and quantum sensing applications in the far-infrared region.
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
Nathalie Lander Gower, Shiran Levy, Silvia Piperno, Sadhvikas J. Addamane, John L. Reno, Asaf Albo
Summary: We conducted an experimental study on a new design for a terahertz quantum cascade laser (THz QCL) that combines two-well injector and direct-phonon scattering schemes. This design improves the performance of the lasers by using a direct phonon scattering scheme for depopulating the lower laser level and reducing the overlap with the doped region. The design also achieves efficient isolation of active laser levels and shows potential for higher operating temperatures than the current records.
APPLIED PHYSICS LETTERS
(2023)
Article
Physics, Applied
Christopher A. Curwen, John L. Reno, Benjamin S. Williams
APPLIED PHYSICS LETTERS
(2020)
Article
Engineering, Electrical & Electronic
C. A. Curwen, J. L. Reno, B. S. Williams
ELECTRONICS LETTERS
(2020)
Article
Physics, Applied
Yu Wu, Sadhvikas Addamane, John L. Reno, Benjamin S. Williams
Summary: A new VECSEL external cavity design is demonstrated to transition from single/double-mode lasing to multi-mode lasing, with up to nine modes lasing simultaneously, paving the way for eventual frequency comb operation.
APPLIED PHYSICS LETTERS
(2021)
Article
Psychology, Biological
James E. Arruda, Jessica Steele, Madison C. McInnis, Vanessa R. Rainey, Aaron Wade
Summary: The study found no significant differences in intra- and inter-individual variability associated with P2 latency or amplitude, but significant differences in amplitude were observed between the two light conditions. While the current practice of using polychromatic white light for FVEP-P2 production remains the gold standard, further research is needed to reduce the natural variability of P2 for it to be used as a biomarker.
INTERNATIONAL JOURNAL OF PSYCHOPHYSIOLOGY
(2021)
Article
Physics, Applied
Yue Shen, Anthony D. Kim, Mohammad Shahili, Christopher A. Curwen, Sadhvikas Addamane, John L. Reno, Benjamin S. Williams
Summary: An amplifying quantum-cascade (QC) metasurface, a key component of the QC vertical-external-cavity surface-emitting-laser (VECSEL), was studied using reflection-mode terahertz time domain spectroscopy. Perfect absorption at zero bias, increase in reflectance with bias, and significant phase modulation associated with metasurface resonance were observed. The results provide insight into the interaction between intersubband QC-gain material and metasurface, and modify the design rules for biased and unbiased QC-VECSELs.
APPLIED PHYSICS LETTERS
(2021)
Article
Optics
Yu Wu, Yue Shen, Sadhvikas Addamane, John L. Reno, Benjamin S. Williams
Summary: This study presents a terahertz quantum-cascade vertical-external-cavity surface-emitting laser (QC-VECSEL) with significant continuous frequency tuning and high efficiency. The device demonstrates laser operation in specific conditions with good performance, but challenges remain for extending the operating wavelength in QC metasurface VECSELs.
Article
Nanoscience & Nanotechnology
Christopher A. Curwen, Sadhvikas J. Addamane, John L. Reno, Mohammad Shahili, Jonathan H. Kawamura, Ryan M. Briggs, Boris S. Karasik, Benjamin S. Williams
Summary: By comparing the performance of 10 and 5 micrometer thick metal-metal waveguide terahertz quantum-cascade laser ridges, it was found that the 5 micron thick material has a higher continuous wave operating temperature and is becoming increasingly important in emerging designs.
Article
Nanoscience & Nanotechnology
Christopher A. Curwen, Mohammad Shahili, Sadhvikas J. Addamane, John L. Reno, Boris S. Karasik, Benjamin S. Williams, Jonathan H. Kawamura
Summary: An active amplifying metasurface based on a quantum-cascade gain material at 2.7 THz was studied. The metasurface demonstrated excellent beam quality and frequency tunability, as well as a peak amplification of approximately 0.3 dB.
Article
Physics, Applied
Yu Wu, Christopher A. Curwen, Darren J. Hayton, John L. Reno, Benjamin S. Williams
Summary: In this study, we demonstrated the continuous wave operation of a terahertz quantum-cascade vertical-external-cavity surface-emitting laser with the use of an external cavity and an off-axis paraboloid mirror. The device showed efficient lasing in the continuous mode with high output power and narrow linewidths.
APPLIED PHYSICS LETTERS
(2022)
Article
Optics
Yu Wu, Christopher A. Curwen, Mohammad Shahili, John L. Reno, Benjamin S. Williams
Summary: This paper demonstrates the use of radiofrequency injection locking and spectral broadening in a terahertz quantum-cascade vertical-external-cavity surface-emitting laser. By injecting RF current modulation, the round-trip frequency can be pulled and locked. The lasing spectrum can be broadened from 14 GHz to a maximum of 110 GHz with injected RF power, opening up possibilities for active mode-locking and picosecond pulse generation in THz lasers.
LASER & PHOTONICS REVIEWS
(2023)
Article
Optics
Christopher a. Curwen, Anthony d. Kim, Boris s. Karasik, Jonathan h. Kawamura, Benjamin s. Williams
Summary: Optical injection locking is achieved for a metasurface quantum-cascade vertical-external-cavity surface-emitting laser at 2.5 THz, using a Schottky diode frequency multiplier chain as the injection source. The spectral properties of the source are effectively transferred to the laser output, with a locked linewidth of -1 Hz and a locking bandwidth of -300 MHz. The study also examines the interaction between the injected signal and external feedback, showing that the locking bandwidth can be increased or decreased relative to the classic locking range depending on the phase of the feedback.
Article
Chemistry, Multidisciplinary
Georgy Fedorov, Roohollah Hafizi, Vyacheslav Semenenko, Vasili Perebeinos
Summary: In this study, the effect of metal deformations on the gate voltage dependence of the conductance of metallic armchair and zigzag carbon nanotube field effect transistors (FETs) was investigated. It was found that the current-voltage characteristics of these FET devices are different from those expected for metallic carbon nanotubes. The gate-voltage dependence of the conductance in armchair CNTFETs shows an ON/OFF ratio of about a factor of two, nearly independent of temperature, attributed to deformation-induced modification of the band structure.
Article
Engineering, Electrical & Electronic
Sidharth Thomas, Sam Razavian, Wei Sun, Benyamin Fallahi Motlagh, Anthony D. Kim, Yu Wu, Benjamin S. Williams, Aydin Babakhani
Summary: This article presents a silicon-based source that can emit power from the lower end of the terahertz spectrum into the far-infrared region. It utilizes a millimeter-wave oscillator and a PIN diode multiplier to generate higher harmonic generation. The chip is characterized and measured at various frequencies using Fourier-transform infrared spectroscopy, confirming the presence of detectable tones in the far-infrared frequencies. This work is a significant breakthrough as it demonstrates the first silicon source capable of generating detectable tones at far-infrared frequencies.
IEEE JOURNAL OF SOLID-STATE CIRCUITS
(2023)
Article
Engineering, Electrical & Electronic
Anthony D. Kim, Christopher A. Curwen, Yu Wu, John L. Reno, Sadhvikas J. Addamane, Benjamin S. Williams
Summary: THz external-cavity lasers based on QC metasurfaces show potential for widely-tunable, high-power output. By using the QC-VECSEL architecture and optimizing the design of the metasurface, continuous broadband tuning and high-quality beam patterns can be achieved.
IEEE JOURNAL OF MICROWAVES
(2023)
Proceedings Paper
Engineering, Electrical & Electronic
Yue Shen, Anthony D. Kim, Christopher A. Curwen, John L. Reno, Benjamin S. Williams
2020 45TH INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER, AND TERAHERTZ WAVES (IRMMW-THZ)
(2020)
