By variational approach, we analyze the characteristics of beam propagation through a cubic optical nonlinear medium using a laser beam that has a transverse elliptic Gaussian profile. The analytic solution to the normalized transmittance at the center of the far field as a function of medium position and the beam characteristics is obtained and compared with the numerical simulation, which is realized by a combination of algorithms. We also analyze the peak-valley transmittance difference as a function of medium length, ellipticity, and a stigmatism. The relationship between peak-valley normalized transmittance difference of the z-scan trace and aperture size or the slit width are obtained. Meanwhile, the comparison of z-scan characteristics with an elliptic Gaussian beam with those using a circular symmetric Gaussian beam is made.
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http://dx.doi.org/10.1364/ao.42.002219 | DOI Listing |
Materials (Basel)
January 2025
College of Mechanical Engineering, Baoji University of Arts and Sciences, Baoji 721016, China.
Accurate analyses of contact problems for rough surfaces are important but complicated. Some assumptions, namely that all asperities can be approximated by a hemisphere with the same radius and assuming a Gaussian distribution of the asperity heights, are convenient but may lead to less accurate results. The purpose of this work is to investigate these assumptions and analyze the conditions under which they are valid.
View Article and Find Full Text PDFEntropy (Basel)
December 2024
Department of Statistics and Data Science, College of Science, Southern University of Science and Technology, Shenzhen 518055, China.
This paper proposes a parametric hierarchical model for functional data with an elliptical shape, using a Gaussian process prior to capturing the data dependencies that reflect systematic errors while modeling the underlying curved shape through a von Mises-Fisher distribution. The model definition, Bayesian inference, and MCMC algorithm are discussed. The effectiveness of the model is demonstrated through the reconstruction of curved trajectories using both simulated and real-world examples.
View Article and Find Full Text PDFHeliyon
January 2024
Department of Civil Engineering, National Institute of Technology Patna, India.
Nowadays, due to the structural advantages gained by combining three different materials' properties, columns made of carbon-fiber reinforced polymer (CFRP)-confined concrete with inner steel tube have received researchers' interest. This article presents the nonlinear finite element analysis and multiple machine learning (ML) model-based study on the behavior of round corner rectangular CFRP-confined concrete short columns reinforced by the inner high-strength elliptical steel tube under the axial load. The reliability of the proposed nonlinear finite element model was verified against the existing experimental investigations.
View Article and Find Full Text PDFJ Chem Phys
December 2024
State Key Laboratory of Precision Spectroscopy, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China.
Using ion-ion coincidence measurements, we experimentally investigate the dissociative triple ionization of argon dimers in relative phase controlled elliptically polarized two-color femtosecond laser fields. By examining the kinetic energy release-dependent momentum angular distribution of the ejected ionic fragments, two distinct pathways, each associated with different intermediates, are identified. Control over the emission directions of the ionic fragments is achieved by varying the relative phase of the elliptical two-color laser fields.
View Article and Find Full Text PDFThis paper discusses the generation of a novel periodic nonlinear error in homodyne interferometers due to geometric misalignments. These misalignments arise from cumulative assembly errors among the sensor head interior, target mirror, test platform, and detector, leading to dynamic misplacement of the measurement beam on the detector's surface. A physical model was developed to explain this error, focusing on the interference field produced by Gaussian beams under conditions of beam separation and inclined interference.
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