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Multiscale and multiphysics problems need novel numerical methods in order for them to be solved correctly and predictively. To that end, we develop a wavelet based technique to solve a coupled system of nonlinear partial differential…

Numerical Analysis · Mathematics 2023-03-22 Cale Harnish , Luke Dalessandro , Karel Matous , Daniel Livescu

Directional couplers are essential components in integrated photonics. Given their widespread use, accurate characterization of directional couplers is crucial for ensuring optimal performance. However, it is challenging due to the coupling…

In this work, we discuss and compare three methods for the numerical approximation of constant- and variable-coefficient diffusion equations in both single and composite domains with possible discontinuity in the solution/flux at…

Numerical Analysis · Mathematics 2021-11-17 Gustav Ludvigsson , Kyle R. Steffen , Simon Sticko , Siyang Wang , Qing Xia , Yekaterina Epshteyn , Gunilla Kreiss

In this work, we introduce a Variational Multi-Scale (VMS) method for the numerical approximation of parabolic problems, where sub-grid scales are approximated from the eigenpairs of associated elliptic operator. The abstract method is…

Four-wave mixing has extensively been investigated for various applications such as communications, spectroscopy, metrology, quantum computing and bio-imaging. However, there is a clear desire to implement these functionalities in a small…

Guided modes of an open periodic waveguide, with a periodicity in the main propagation direction, are Bloch modes confined around the waveguide core with no radiation loss in the transverse directions. Some guided modes can have a complex…

Optics · Physics 2020-10-28 Amgad Abdrabou , Ya Yan Lu

Guided waves modes in a slab waveguide formed from the isotropic dielectric layer embedded by hyperbolic materials are investigated. Optical axis is normal to the slab plane. The dispersion relations for TE and TM waves are found. The…

Optics · Physics 2015-07-28 Ekaterina I. Lyashko , Andrey I. Maimistov

Monitoring polarization dynamics in multimode fibers is critical for a range of applications, spanning from optical communication to sensing. Although the modal behavior of multimode fibers is well understood through interferometry and…

Optics · Physics 2025-03-07 Harikumar K. Chandrasekharan , Ross Donaldson

In this work, we study two-dimensional diffusion-wave equations with variable exponent, modeling mechanical diffusive wave propagation in viscoelastic media with spatially varying properties. We first transform the diffusion-wave model into…

Numerical Analysis · Mathematics 2025-09-26 Hao Zhang , Kexin Li , Wenlin Qiu

Photonic crystals with a finite size can support surface modes when appropriately terminated. We calculate the dispersion curves of surface modes for different terminations using the plane wave expansion method. These non-radiative surface…

Waveguide characterization of dielectric materials is a convenient and broadband approach for measuring dielectric constant. In conventional microwave measurements, material samples are usually mechanically shaped to fit the waveguide…

Applied Physics · Physics 2022-04-20 Xuchen Wang , Sergei A. Tretyakov

We consider finite element methods of multiscale type to approximate solutions for two-dimensional symmetric elliptic partial differential equations with heterogeneous $L^\infty$ coefficients. The methods are of Galerkin type and follow the…

Numerical Analysis · Mathematics 2025-05-20 Alexandre L. Madureira , Marcus Sarkis

We propose a variational technique to optimize for generalized barycentric coordinates that offers additional control compared to existing models. Prior work represents barycentric coordinates using meshes or closed-form formulae, in…

Graphics · Computer Science 2023-10-09 Ana Dodik , Oded Stein , Vincent Sitzmann , Justin Solomon

We introduce a variational multiscale closure modeling strategy for the numerical stabilization of proper orthogonal decomposition reduced-order models of convection-dominated equations. As a first step, the new model is analyzed and tested…

Numerical Analysis · Mathematics 2015-03-19 Traian iliescu , Zhu Wang

The quasi-one-dimensional rhombic array of the waveguides is considered. System of equations describing coupled waves in the waveguide in the linear limit is solved exactly. The electric field distribution was found both for the…

Optics · Physics 2016-06-14 Andrey I. Maimistov , Viktor A. Patrikeev

Common techniques for measuring refractive indices, such as ellipsometry and goniometry, are ineffective for van der Waals crystal flakes because of their high anisotropy and small, micron-scale, lateral size. To address this, we employ…

Mesoscale and Nanoscale Physics · Physics 2025-07-21 Martin Nørgaard , Torgom Yezekyan , Stefan Rolfs , Christian Frydendahl , N. Asger Mortensen , Vladimir A. Zenin

We present ModMap, a natively multiview and multimodal framework for 3D anomaly detection and segmentation. Unlike existing methods that process views independently, our method draws inspiration from the crossmodal feature mapping paradigm…

Computer Vision and Pattern Recognition · Computer Science 2026-04-03 Alex Costanzino , Pierluigi Zama Ramirez , Giuseppe Lisanti , Luigi Di Stefano

In this paper we propose an algorithm for the detection of edges in images that is based on topological asymptotic analysis. Motivated from the Mumford--Shah functional, we consider a variational functional that penalizes oscillations…

Numerical Analysis · Mathematics 2013-06-12 E. Beretta , M. Grasmair , M. Muszkieta , O. Scherzer

Electroelastic waves in piezoelectric media are widely used in sensing and filtering applications. Despite extensive research, computing the guided wave dispersion remains challenging. This paper presents semi-analytical approaches based on…

Applied Physics · Physics 2025-06-18 Daniel A. Kiefer , Georg Watzl , Katharina Burgholzer , Martin Ryzy , Clemens Grünsteidl

We demonstrate that the spatial profiles of both propagating and evanescent Bloch-modes in a periodic structure can be extracted from a single measurement of electric field at the specified optical wavelength. We develop a systematic…