Quantum cascade lasers are a unique laboratory for studying nonlinear laser dynamics because of their high intracavity intensity, strong intersubband optical nonlinearity, and an unusual combination of relaxation time scales. Here we investigate the nonlinear coupling between the transverse modes of quantum cascade lasers. We present evidence for stable phase coherence of multiple transverse modes over a large range of injection currents. We explain the phase coherence by a four-wave mixing interaction originating from the strong optical nonlinearity of the gain transition. The phase-locking conditions predicted by theory are supported by spectral data and both near- and far-field mode measurements.
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http://dx.doi.org/10.1103/PhysRevLett.102.013901 | DOI Listing |
Sci Rep
January 2025
School of Electrical Engineering, University of Tehran, Tehran, 14179-35840, Iran.
This paper introduces an analytical method for studying power transmission through an infinite array of helical-shaped metal particles in a lossy dielectric medium. While the assessment of composite slabs' transmitted power has been extensively researched in the electromagnetic interference (EMI) shielding field, many studies lack an adequate problem description. The primary inadequacy of these studies is the need for an analytical framework.
View Article and Find Full Text PDFDirac-vortex cavities have single-mode emitting, scalable mode areas, arbitrary mode degeneracies, and vector-beam vertical emission, which attract more and more researchers' attention. Here, we demonstrate the single-mode of two-dimensional transverse magnetic (TM) Dirac-vortex topological cavity modes that are not only generally available for high power topological surface-emitting lasers (TCSEL) but also are one of the excellent candidates for refractive index sensors. The principle for winding number is studied, and the scaling laws are shown with cavity mode diameters.
View Article and Find Full Text PDFActa Biomater
January 2025
Department of Industrial Engineering, Alma Mater Studiorum - University of Bologna, Via Terracini 28, 40131 Bologna, Italy. Electronic address:
Intervertebral disc (IVD) degeneration is suspected to affect the distribution of stress and strain near the vertebral endplates and in the underlying bone. This scenario is worsened by the presence of metastatic lesions on the vertebrae (primarily thoracic vertebrae (60-80 %)) which increase the risk of fracture. As such, this study aimed to evaluate the effect of IVD degeneration on the internal volumetric strains and failure modes of human metastatic vertebral bodies.
View Article and Find Full Text PDFLangmuir
January 2025
Department of Chemical and Environmental Engineering, University of Cincinnati, Cincinnati, Ohio 45220, United States.
Solvent toxicity limits -butanol fermentation titer, increasing the cost and energy consumption for subsequent separation processes and making biobased production more expensive and energy-intensive than petrochemical approaches. Amphiphilic solvents such as -butanol partition into the cell membrane of fermenting microorganisms, thinning the transverse structure, and eventually causing a loss of membrane potential and cell death. In this work, we demonstrate the deleterious effects of -butanol partitioning upon the lateral dimension of the membrane structure, called membrane domains or lipid rafts.
View Article and Find Full Text PDFMaterials (Basel)
December 2024
Department of Mechanical Engineering, North Carolina A & T State University,1601 E. Market Street, Greensboro, NC 27411, USA.
Damage in composite laminates evolves through complex interactions of different failure modes, influenced by load type, environment, and initial damage, such as from transverse impact. This paper investigates damage growth in cross-ply polymeric matrix laminates under tensile load, focusing on three primary failure modes: transverse matrix cracks, delaminations, and fiber breaks in the primary loadbearing 0-degree laminae. Acoustic emission (AE) techniques can monitor and quantify damage in real time, provided the signals from these failure modes can be distinguished.
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