We develop a model for the description of nonlinear pulse propagation in multimode optical fibers with a parabolic refractive index profile. It consists of a 1+1D generalized nonlinear Schrödinger equation with a periodic nonlinear coefficient, which can be solved in an extremely fast and efficient way. The model is able to quantitatively reproduce recently observed phenomena like geometric parametric instability and broadband dispersive wave emission. We envisage that our equation will represent a valuable tool for the study of spatiotemporal nonlinear dynamics in the growing field of multimode fiber optics.
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http://dx.doi.org/10.1364/OL.42.004004 | DOI Listing |
Adv Mater
January 2025
School of Electric Power Engineering, South China University of Technology, Guangzhou, 510641, China.
Self-adaptive dielectrics (SADs), with the characteristics of rapid charge dissipation in electric field distortion, is regarded as the future material for package insulation of advanced electronic devices. The current landscape of SADs is incapable to achieve tunable nonlinear electrical conductivity and threshold field strength due to the inherent Schottky barrier, significantly limiting the application scenarios of SADs. Here, a strategy is reported to construct a stepped Schottky barrier through virus-like structures, which are composed of subminiature metal particles and semiconductor microspheres.
View Article and Find Full Text PDFUltrasonics
January 2025
College of Aerospace Engineering, Chongqing University, Chongqing 400044, China. Electronic address:
This study delves into the feasibility of leveraging quasi-static component (QSC) generation during primary Lamb wave propagation to discern subtle alterations in the interfacial properties of a two-layered plate. Unlike the second-harmonic generation of Lamb waves, QSC generation doesn't necessitate precise phase-velocity matching but rather requires an approximate matching of group velocities to ensure the emergence of cumulative growth effects. This unique characteristic empowers the QSC-based nonlinear ultrasonic method to effectively surmount the limitations associated with inherent dispersion and multimode traits of Lamb wave propagation.
View Article and Find Full Text PDFSensors (Basel)
January 2025
Department of Electronics Engineering, Kaunas University of Technology, 51368 Kaunas, Lithuania.
The application of spread-spectrum signals (arbitrary pulse width and position (APWP) sequences) in air-coupled resonant ultrasound spectroscopy is studied. It was hypothesized that spread-spectrum signal optimization should be based on te signal to noise ratio (SNR). Six APWP signal optimization criteria were proposed for this purpose.
View Article and Find Full Text PDFNano Lett
January 2025
Department of Mechanical Engineering, the University of Texas at Dallas, Richardson, Texas 75080, United States.
Plasmonic nanomaterials are effective photoacoustic (PA) contrast agents with diverse biomedical applications. While silica coatings on gold nanoparticles (AuNPs) have been demonstrated to increase PA efficiency, the underlying mechanism remains elusive. Here, we systematically investigated the impact of silica coatings on PA generation under picosecond and nanosecond laser pulses.
View Article and Find Full Text PDFMedicine (Baltimore)
January 2025
Teaching Office, Second People's Hospital of Shenzhen (First Affiliated Hospital of Shenzhen University), Shenzhen City, China.
Previous studies have provided relatively limited evidence in examining the impact of preoperative serum albumin levels on the length of hospital stay (LOS) in patients with hip fractures. This study aimed to elucidate the association between preoperative serum albumin levels and LOS in elderly patients with hip fractures. This retrospective cohort study included 1444 elderly patients undergoing surgical treatment for hip fractures at the Second People's Hospital of Shenzhen from January 2012 to December 2021.
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