Article
Physics, Applied
S. Arslan, H. Wenzel, J. Fricke, A. Thies, A. Ginolas, B. Eppich, G. Traenkle, P. Crump
Summary: Spatial-hole-burning is studied as a limitation to the continuous-wave output power of GaAs-based diode lasers. Experimental data shows that carrier density in the device center rises rapidly at the rear facet and falls at the front, consistent with simulation. Lateral carrier accumulation is observed at the edge of the laser stripe, indicating increased local current flow.
APPLIED PHYSICS LETTERS
(2023)
Article
Optics
Carlo Silvestri, Xiaoqiong Qi, Thomas Taimre, Aleksandar D. Rakic
Summary: This article presents a study on the dynamics of dense and harmonic coherent regimes in quantum cascade lasers (QCLs) emitting in the terahertz (THz) spectral region. The study reproduces the main features of optical frequency combs and harmonic frequency combs in this region, analyzes the effect of current modulation on system locking, and provides a procedure for generating short duration and high contrast pulses. Furthermore, the study demonstrates the generation of sequences of pulses with a repetition frequency that is a multiple of the free-spectral range (FSR) of the laser cavity, showing promising results for various applications.
Article
Engineering, Electrical & Electronic
Jae Ha Ryu, Benjamin Knipfer, Jeremy D. Kirch, Robert A. Marsland, Dan Botez, Tom Earles, Chris Galstad, Morgan Turville-Heitz, Chris Sigler, Axel Stromberg, Yan-Ting Sun, Sebastian Lourdudoss, Luke J. Mawst
Summary: We present a novel reverse-taper quantum cascade laser (QCL) that can scale the output power while maintaining good beam quality. The device structure and fabrication process enable mode filtering and beam stability. Experimental results demonstrate high-quality beam output within a certain power range.
IEEE PHOTONICS JOURNAL
(2022)
Article
Quantum Science & Technology
Nicola Biagi, Luca S. Costanzo, Marco Bellini, Alessandro Zavatta
Summary: The newly developed technique of delocalized single photon addition can generate discorrelation, a new joint statistical property of multimode quantum light states where the number of photons in each mode can take any value individually, but two modes together never exhibit the same. The first experimental observation of discorrelation is provided by coherently adding a single photon to two identical coherent states of light in different temporal modes. The capability of manipulating this statistical property has practical applications in scenarios involving the secure distribution of information among untrusted parties.
ADVANCED QUANTUM TECHNOLOGIES
(2021)
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.
Correction
Physics, Multidisciplinary
A. D. Brynes, P. Smorenburg, I Akkermans, E. Allaria, L. Badano, S. Brussaard, M. Danailov, A. Demidovich, G. De Ninno, D. Gauthier, G. Gaio, S. B. van der Geer, L. Giannessi, M. J. de Loos, N. S. Mirian, G. Penco, P. Rebernik, F. Rossi, I Setija, S. Spampinati, C. Spezzani, M. Trovo, P. H. Williams, S. Di Mitri
Summary: This paper serves as an addendum to a previous reference, in which the transverse emittance growth in a bunch compressor of a free-electron laser due to CSR was studied. Analytic results based on CSR theory were compared with experimental and simulation results, showing improved agreement when the bunch compression approaches its maximum value. Recent corrections to the theoretical emittance growth have resulted in a smaller increase than previously expected.
NEW JOURNAL OF PHYSICS
(2021)
Article
Optics
Hua Li, Wenjian Wan, Ziping Li, J. C. Cao, Sylvie Lepillet, Jean-Francois Lampin, Kevin Froberger, Lorenzo Columbo, Massimo Brambilla, Stefano Barbieri
Summary: This study investigates the dynamics of multimode THz QCLs using a self-detection technique combined with a real-time oscilloscope. A self-starting periodic modulation of the laser current is observed, and two distinct regimes of oscillation with different coherence times are identified depending on the drive current. The measurements are interpreted using effective semiconductor Maxwell-Bloch equations, revealing the phase relationship between carrier density and optical pulses.
Article
Biochemistry & Molecular Biology
Habibur Rahman, Hazrat Ali, Rafi Ud Din, Iftikhar Ahmad, Mahidur R. Sarker, Sawal Hamid Md Ali
Summary: The study investigates the surface plasmon-induced spectral hole burning at the silver-dielectric interface, with the introduction of spontaneous generated coherence leading to a normal dispersion slope and enhancement of hole burning effect. The propagation length of SPP in the hole-burning region is greatly enhanced under the effect of SGC and can be modified and controlled with the frequency and intensity of the driving fields.
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
Physics, Multidisciplinary
Aleksandra Gajic, Jelena Radovanovic, Nikola Vukovic, Vitomir Milanovic, Dmitri L. Boiko
Summary: This study investigates the influence of a magnetic field on multimode self-pulsations, revealing that an external magnetic field can slow down decoherence and diffusion rates in quantum cascade lasers, reducing the pump current required to achieve self-pulsations. As the magnetic field strength increases, the self-pulsation frequency and spectrum width remain practically unchanged.
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
Nanoscience & Nanotechnology
Franco Prati, Massimo Brambilla, Marco Piccardo, Lorenzo Luigi Columbo, Carlo Silvestri, Mariangela Gioannini, Alessandra Gatti, Luigi A. Lugiato, Federico Capasso
Summary: Nonlinear interactions in physical systems can lead to symmetry breaking phenomena such as modulation instabilities, which may result in the formation of optical solitons. The generalized Lugiato-Lefever equation predicts the existence of optical solitons in ring quantum cascade lasers with an external driving field, enabling the bistability mechanism. The study also shows the possibility of phase solitons and cavity solitons formation in the driven emitter, making them promising for applications such as frequency combs and encoding information.
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, Fluids & Plasmas
Xiang Chen, I. H. Hutchinson
Summary: In this study, we perform a three-dimensional linear stability analysis of an initially planar electron hole structure using the Vlasov-Poisson method. The distribution function is solved by integrating along unperturbed orbits. The non-sinusoidal potential perturbation shape (parallel to B) is expanded in eigenfunctions of the adiabatic Poisson operator, which modifies the shiftmode assumption. By integrating over a continuum of wave-like modes, the continuous perturbation can be effectively approximated by a single mode that satisfies the external wave dispersion relation, resulting in a perturbation composed of three weighted modes. The multimode analysis refines the accuracy of the previous single-mode results, leading to slightly higher growth rates and explaining the observations of instability beyond the prior shiftmode thresholds in particle-in-cell simulations.
JOURNAL OF PLASMA PHYSICS
(2023)
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, Multidisciplinary
Mehran Shahmohammadi, Martin J. Sueess, Romain Peretti, Filippos Kapsalidis, Andres Forrer, Mattias Beck, Jerome Faist
Summary: The article introduces a laser system with controllable gain and loss, and demonstrates the observation of spectral singularities by tuning the coupling strength and gain difference between modes. The dual section QCL provides an ideal platform for studying spectral singularities.
NEW JOURNAL OF PHYSICS
(2022)
Article
Optics
Enrico Casamenti, Gozden Torun, Luciano Borasi, Maxime Lautenbacher, Mathieu Bertrand, Jerome Faist, Andreas Mortensen, Yves Bellouard
Summary: Chalcogenide glass has wide transmission window, high refractive index, and nonlinear optical properties in the infrared range. However, the poor mechanical properties and low chemical and environmental stability make it challenging to produce three-dimensional microstructures. In this study, the combination of femtosecond laser-assisted chemical etching and pressure-assisted infiltration is used to fabricate chalcogenide-silica micro-glass composites with geometrically complex 3D structures. The resulting products have a high refractive index contrast for total-internal-reflection guiding and suitable optical quality roughness level for infrared applications.
Article
Multidisciplinary Sciences
Felice Appugliese, Josefine Enkner, Gian Lorenzo Paravicini-Bagliani, Mattias Beck, Christian Reichl, Werner Wegscheider, Giacomo Scalari, Cristiano Ciuti, Jerome Faist
Summary: Controlling electronic properties of materials through the vacuum fields of cavity electromagnetic resonators is a frontier in condensed matter physics. We found that enhanced vacuum field fluctuations in subwavelength split-ring resonators strongly affect quantum Hall electron transport. The breakdown of topological protection in the integer quantum Hall effect is attributed to long-range cavity-mediated electron hopping induced by vacuum fluctuations.
Article
Multidisciplinary Sciences
Shima Rajabali, Sergej Markmann, Elsa Jochl, Mattias Beck, Christian A. Lehner, Werner Wegscheider, Jerome Faist, Giacomo Scalari
Summary: This study demonstrates terahertz time-domain spectroscopy of an individual subwavelength meta-atom using an asymmetric immersion lens setup and a complementary resonating meta-surface. The linewidth dependence and ultrastrongly coupled Landau polaritons are investigated, providing insights into the control of light-matter interaction at the single electron/resonator level. The proposed technique has potential applications in characterizing complex conductivity in micron-sized samples in the terahertz domain.
NATURE COMMUNICATIONS
(2022)
Article
Physics, Applied
Martin Franckie, Mathieu Bertrand, Jerome Faist
Summary: This article introduces a method for calculating the linewidth enhancement factor (LEF) in a semiconductor laser, which combines a nonequilibrium Green's function model and simulates the material response to the fluctuation of optical intensity. It can consider all relevant electronic effects and predicts the LEF of a quantum cascade laser to be in the range of 0.1-1. Many-body effects, off-resonant transitions, dispersive gain, counter-rotating terms, intensity-dependent transition energy, and precise subband distributions all significantly contribute to the LEF and are important for accurate simulations.
APPLIED PHYSICS LETTERS
(2023)
Article
Chemistry, Analytical
Akshay Nataraj, Bela Tuzson, Michele Gianella, Ivan Prokhorov, Gang Li, Volker Ebert, Jerome Faist, Lukas Emmenegger
Summary: This study presents a direct and nondestructive analytical technique using quantum cascade laser absorption spectroscopy to quantify the isotopic distribution of propane at different positions. Spectral information of propane isotopomers was obtained using a high-resolution Fourier-transform infrared (FTIR) spectrometer, and suitable mid-infrared regions were selected for accurate measurement. Precision measurements of isotopically substituted non-methane hydrocarbons were achieved for the first time using laser absorption spectroscopy.
ANALYTICAL CHEMISTRY
(2023)
Article
Optics
Philipp Taeschler, Andres Forrer, Mathieu Bertrand, Filippos Kapsalidis, Mattias Beck, Jerome Faist
Summary: In recent years, there has been significant interest in optical frequency combs with frequency modulated output. This study demonstrates an asynchronous optical sampling technique that operates directly in the time domain. By using a mid-infrared quantum cascade laser frequency comb, they were able to measure both the instantaneous intensity and optical frequency of the comb. The results show a quasi-constant intensity output and a close to linear frequency chirp, consistent with phase-resolved spectral measurements. In contrast to previous works, stable phase-locking is achieved with positive intracavity dispersion, leading to an inversion of the observed frequency modulation.
LASER & PHOTONICS REVIEWS
(2023)
Article
Optics
G. Torrioli, A. Forrer, M. Beck, P. Carelli, F. Chiarello, J. Faist, A. Gaggero, E. Giovine, F. Martini, U. Senica, R. Leoni, G. Scalari, S. Cibella
Summary: We investigate the performance of a hot-electron bolometer (HEB) operating at THz frequencies by employing superconducting niobium nitride films. We present the voltage response of the detector, measured with different THz sources, over a wide electrical detection bandwidth. Our results reveal that the impulse response of the fully packaged HEB at 7.5 K exhibits a 3 dB cutoff at around 2 GHz. Notably, the detection capability is still observed above 30 GHz in a heterodyne beating experiment utilizing a THz quantum cascade laser frequency comb. Additionally, we evaluate the HEB sensitivity and measure an optical noise equivalent power (NEP) of 0.8 pW/√Hz at 1 MHz.
Article
Optics
Philipp Taschler, Lucius Miller, Filippos Kapsalidis, Mattias Beck, Jerome Faist
Summary: By leveraging the picosecond carrier dynamics observed in quantum cascade lasers (QCLs), we have successfully generated 33 ps optical pulses with watt-level peak power using short electrical excitations. Optical injection seeding ensured lasing on a single resonator mode, and the resulting pulses were characterized in both time and frequency domains. These results open new pathways for the generation of highly tunable, high power mid-infrared pulses from a monolithic source.
Article
Physics, Multidisciplinary
Sergej Markmann, Martin Franckie, Mathieu Bertrand, Mehran Shahmohammadi, Andres Forrer, Pierre Jouy, Mattias Beck, Jerome Faist, Giacomo Scalari
Summary: Fast and high-resolution Fourier transform spectrometers are important for studying complex chemical and biological reactions. The authors developed a rotational FT spectrometer that decouples spectral and temporal resolution, allowing for high-speed spectroscopy. They also demonstrated the use of a single comb source for Mid-IR dual-comb spectroscopy.
COMMUNICATIONS PHYSICS
(2023)
Article
Optics
Urban Senica, Alexander Dikopoltsev, Andres Forrer, Sara Cibella, Guido Torrioli, Mattias Beck, Jerome Faist, Giacomo Scalari
Summary: This study demonstrates the generation of self-starting frequency-modulated combs by enhancing the gain saturation dynamics and nonlinearities through spatial modulation in semiconductor lasers. Using terahertz quantum cascade lasers and taking advantage of spatial confinement, pure frequency-modulated combs with flat intensity spectra and clear linear frequency chirps can be generated.
LASER & PHOTONICS REVIEWS
(2023)
Article
Optics
B. Chomet, T. Gabbrielli, D. Gacemi, F. Cappelli, L. Consolino, P. De Natale, F. Kapsalidis, A. Vasanelli, Y. Todorov, J. Faist, C. Sirtori
Summary: In quantum cascade laser frequency combs, the intensity distribution of the optical spectrum can be split into two well-separated lobes of longitudinal modes that, even when far apart, have a common phase relation and preserve equal frequency separation. The temporal dynamics of two lasers emitting at 4.4 and 8.1 mu m operating in this bilobed regime are investigated. The laser intensity shows a peculiar temporal behavior associated with the spectral features whereby, every half a round-trip, the total emitted power switches from one lobe to the other, with a perfect temporal anti-correlation.
Article
Optics
Kenichi N. N. Komagata, Alexandre Parriaux, Mathieu Bertrand, Johannes Hillbrand, Mattias Beck, Valentin J. J. Wittwer, Jerome Faist, Thomas Sudmeyer
Summary: We use a low power near-infrared laser as an optical actuator to control a mid-infrared frequency comb. By controlling the current and intensity of the lasers, we achieve tight phase lock and low phase noise. We also show that the quantum cascade laser can act as a fast near-infrared light detector and injection locking can be achieved through modulation of the near-infrared light.
Article
Materials Science, Multidisciplinary
Ivan Fotev, Stephan Winnerl, Saicharan Aswartham, Sabine Wurmehl, Bernd Buechner, Harald Schneider, Manfred Helm, Alexej Pashkin
Summary: In this study, the suppression of spin density wave (SDW) order in BaFe2As2 under pressure was investigated using optical pump-probe technique. The results show that the pressure-induced suppression of SDW order at low temperature occurs gradually, in contrast to the thermally induced SDW transition. This suggests that the pressure-driven quantum phase transition in BaFe2As2 (and probably other iron pnictides) is continuous and it is caused by the gradual worsening of the Fermi-surface nesting conditions.
Article
Materials Science, Multidisciplinary
Tecla Gabbrielli, Natalia Bruno, Nicola Corrias, Simone Borri, Luigi Consolino, Mathieu Bertrand, Mehran Shahmohammadi, Martin Franckie, Mattias Beck, Jerome Faist, Alessandro Zavatta, Francesco Cappelli, Paolo De Natale
Summary: This study presents a novel approach to investigate harmonic frequency combs emitted by quantum cascade lasers (QCLs), revealing the presence of intensity correlations among the twin modes characterizing the emission spectra. The findings hold significance for engineering a new generation of semiconductor devices that can emit light with quantum properties.
ADVANCED PHOTONICS RESEARCH
(2022)
