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We review our recent work leading to steady-state solutions of the semiclassical (Maxwell-Bloch) equations of a laser. These are coupled non-linear partial differential equations in space and time which have previously been solved either by…

We derive a sharp spectral estimate for a superlinear free boundary problem arising in plasma physics. The semilinear equation is coupled with a constraint, which forces the analysis of a non-local eigenvalue equation. Consequently the…

Analysis of PDEs · Mathematics 2026-04-03 Daniele Bartolucci , Aleks Jevnikar , Juncheng Wei , Ruijun Wu

Pinch point is a spectral discontinuity found in the neutron diffraction image of spin ice. Similar spectral singularity is commonly observed in a broad range of systems that have a close connection with flat bands. We focus on the electron…

Materials Science · Physics 2024-04-23 Masafumi Udagawa , Hiroki Nakai , Chisa Hotta

Bounding energetic growth of gyrokinetic instabilities is a complementary approach to linear instability analyses involving normal eigenmodes. Previous work has focused on upper bounds which are valid linearly and nonlinearly. However, if…

Plasma Physics · Physics 2025-05-26 P. J. Costello , G. G. Plunk

Narrowband x- and gamma-ray sources based on the inverse Compton scattering of laser pulses suffer from a limitation of the allowed laser intensity due to the onset of nonlinear effects that increase their bandwidth. It has been suggested…

Plasma Physics · Physics 2015-06-23 D. Seipt , S. G. Rykovanov , A. Surzhykov , S. Fritzsche

In this work, we predict that periodic structures without gain and loss do not exhibit an S-shaped hysteresis curve in the presence of saturable nonlinearity (SNL). Instead, the input-output characteristics of the system admit ramp-like…

Optics · Physics 2024-04-23 S. Vignesh Raja , A. Govindarajan , M. Lakshmanan

By measuring energy spectra of the electron emission from a sharp tungsten tip induced by few-cycle laser pulses, the laser-field dependence of the emission mechanism was investigated. In strong laser fields, we confirm the appearance of…

Semiclassical equations of lasing dynamics are re-derived for a lasing medium in a cavity with a spatially non-uniform dielectric constant. It is shown that the non-uniformity causes a radiative coupling between modes of the empty cavity.…

Disordered Systems and Neural Networks · Physics 2009-11-11 Lev Deych

Inspired by the idea of non-Hermitian spectral engineering and non-Hermitian skin effect, a novel design for stable emission of coupled laser arrays with tunable phase locking and strong supermode competition suppression is suggested. We…

Optics · Physics 2022-04-14 Stefano Longhi

Computer simulations with Synopsys' Sentaurus TCAD of opto-electrical characteristics of separate-confinement heterostructure laser based on AlGaAs are used as an example to study the role of the width and depth of Quantum Well (QW) active…

Materials Science · Physics 2011-12-02 Zbigniew Koziol

Guided wave modes in a symmetric slab waveguide formed by an isotropic dielectric layer with cubic nonlinear response placed in the hyperbolic surrounding medium are investigated theoretically. Optical axis of the hyperbolic medium is…

Optics · Physics 2017-03-01 Ekaterina I. Lyashko , Andrei I. Maimistov

The objective of the present study is to explore the connection between the nonlinear normal modes of an undamped and unforced nonlinear system and the isolated resonance curves that may appear in the damped response of the forced system.…

We show how calculable IR loop effects impact positivity bounds in Effective Field Theories with causal and unitary UV completions. We identify infrared singularities which appear in dispersion relations at $|t|\lesssim m^2$. In the…

High Energy Physics - Theory · Physics 2022-11-23 Brando Bellazzini , Marc Riembau , Francesco Riva

This paper describes a calculation of the spontaneous emission limited linewidth of a semiconductor laser consisting of hybrid or heterogeneously integrated, silicon and III-V intracavity components. Central to the approach are a)…

Optics · Physics 2021-12-22 Weng W. Chow , Yating Wan , John E. Bowers , Frédéric Grillot

Supersymmetric non-linear sigma-models are described by a field dependent Kaehler metric determining the kinetic terms. In general it is not guaranteed that this metric is always invertible. Our aim is to investigate the symmetry structure…

High Energy Physics - Theory · Physics 2011-10-11 T. S. Nyawelo , F. Riccioni , J. W. van Holten , S. Groot Nibbelink

We explore a new class of Distributed Feedback (DFB) structures that employ the recently-developed concept of Parity-Time (PT) symmetry in optics. We demonstrate that, based on PT-symmetric pure reflective volume gratings, vertical cavity…

Optics · Physics 2015-10-29 H. F. Jones , Mykola Kulishov

Spectra of Thomson and Compton radiation, emitted during electron scattering off an intense laser beam, are calculated using the frameworks of classical and strong-field quantum electrodynamics, respectively. Both approaches use a…

Atomic Physics · Physics 2013-11-22 M Twardy , K Krajewska , J Z Kamiński

Laser speckle is generated by the multiple interference of light through a disordered medium. Here we study the premise that the speckle pattern retains information about the polarisation state of the incident field. We analytically verify…

Optics · Physics 2020-05-13 Morgan Facchin , Graham D. Bruce , Kishan Dholakia

Nonlinearity in coherent fiber links is fundamentally driven by the temporal statistics and spectral structure of signal intensity. This paper develops a unified framework that links block-level energy statistics of shaped constellations to…

Signal Processing · Electrical Eng. & Systems 2026-03-06 Ravneel Prasad , Emanuele Viterbo

The behavior of a newly introduced overlap parameter is analyzed, measuring the correlation between intensity fluctuations of waves in random media in different physical regimes, with varying amount of disorder and non-linearity. Its…

Statistical Mechanics · Physics 2015-12-01 Fabrizio Antenucci , Andrea Crisanti , Luca Leuzzi