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Related papers: Probing dynamics of time-varying media: Beyond abr…

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During the last decade, possibilities to realize new phenomena and create new applications by varying system properties in time have gained increasing attention in many research fields, spanning a wide range from acoustics to optics. While…

Classical Physics · Physics 2022-11-24 G. Ptitcyn , M. S. Mirmoosa , A. Sotoodehfar , S. A. Tretyakov

Propagation, transmission and reflection properties of linearly polarized plane waves and arbitrarily short electromagnetic pulses in one-dimensional dispersionless dielectric media possessing an arbitrary space-time dependence of the…

When an electromagnetic (EM) wave is propagating in a medium whose properties are varied abruptly in time, the wave experiences refractions and reflections known as "time-refractions" and "time-reflections", both manifesting spectral…

Applied Physics · Physics 2023-10-05 Thomas R. Jones , Alexander V. Kildishev , Mordechai Segev , Dimitrios Peroulis

We investigate the transition radiation on a periodically deformed interface between two dielectric media. Under the assumption that the dielectric permittivities of the media are close, a formula is derived for the spectral-angular…

Optics · Physics 2016-03-16 A. R. Mkrtchyan , A. P. Potylitsyn , V. R. Kocharyan , A. A. Saharian

We derive analytical expressions to describe how light is frequency-shifted when interacting with ultrasound within scattering media, due to the modulation of the refractive index induced by the ultrasound pressure waves. The model is…

Optics · Physics 2024-10-16 Adam Kinos

We study the propagation of electromagnetic waves in tenuous plasmas, where the wave frequency, $\omega_0$, is much larger than the plasma frequency, $\omega_{\rm P}$. We show that in pair plasmas nonlinear effects are weak for $a_0 \ll…

High Energy Astrophysical Phenomena · Physics 2024-09-09 Emanuele Sobacchi , Masanori Iwamoto , Lorenzo Sironi , Tsvi Piran

We present a study of sound wave propagation in a time dependent random medium and an application to imaging. The medium is modeled by small temporal and spatial random fluctuations in the wave speed and density, and it moves due to an…

Analysis of PDEs · Mathematics 2018-06-19 Liliana Borcea , Josselin Garnier , Knut Solna

We report an experimental investigation of the statistical time dynamic of spatial Fourier modes in a fully developped turbulent jet flow. Measurements rely on an original acoustic scattering technique, allowing the direct and continuous…

Statistical Mechanics · Physics 2009-11-11 C. Poulain , N. Mazellier , Y. Gagne , C. Baudet

Time-varying optical materials have attracted recent interest for their potential to enable frequency conversion, nonreciprocal physics, photonic time-crystals, and more. However, the description of time-varying materials has been primarily…

The diffusion model is used to calculate the time-averaged flow of particles in stochastic media and the propagation of waves averaged over ensembles of disordered static configurations. For classical waves exciting static disordered…

Disordered Systems and Neural Networks · Physics 2024-01-11 Azriel Z. Genack , Yiming Huang , Asher Maor , Zhou Shi

Time-varying metamaterials and photonic time crystals offer a powerful route to wave amplification through temporal modulation of material parameters. Here, we experimentally demonstrate amplified up-conversion of free-space electromagnetic…

Space-time varying media enable unprecedented control over electromagnetic waves, yet most existing studies assume idealized, nondispersive materials and thus fail to capture the intrinsic frequency dispersion of realistic platforms. Here,…

Optics · Physics 2025-12-16 Klaas De Kinder , Christophe Caloz

Time-varying metamaterials are artificial materials whose electromagnetic properties change over time. Similar to a spatial medium discontinuity, a sudden change in time of the metamaterial refractive index induces the generation of a…

Classical Physics · Physics 2025-02-06 Davide Ramaccia , Alessandro Toscano , Filiberto Bilotti

A method is proposed for the analysis of the propagation of electromagnetic waves through a homogeneous slab of a medium with Drude-Lorentz dispersion behavior, and excited by a causal sinusoidal source. An expression of the time dependent…

Optics · Physics 2016-10-13 Mohamed Ismail , Boris Gralak

We consider photonic tunnelling through evanescent regions and obtain general analytic expressions for the transit (phase) time $\tau$ (in the opaque barrier limit) in order to study the recently proposed ``universality'' property according…

Optics · Physics 2008-12-18 S. Esposito

Forward transition radiation is considered in an ultrasonic superlattice excited in a finite thickness plate under oblique incidence of relativistic electrons. We investigate the influence of acoustic waves on both the intensity and…

Accelerator Physics · Physics 2012-03-09 A. R. Mkrtchyan , V. V. Parazian , A. A. Saharian

We investigate the influence of the temporal variations of various medium parameters on the propagation of Dirac-type waves in materials where the quasiparticles are described by a generalized version of the pseudospin-1/2 Dirac equation.…

Mesoscale and Nanoscale Physics · Physics 2023-06-21 Seulong Kim , Kihong Kim

We quantify the strength of the waves and their impact on the energy cascade in rotating turbulence by studying the wave number and frequency energy spectrum, and the time correlation functions of individual Fourier modes in numerical…

Fluid Dynamics · Physics 2015-06-17 P. Clark di Leoni , P. J. Cobelli , P. D. Mininni , P. Dmitruk , W. H. Matthaeus

The diffusion behavior of particles moving in complex heterogeneous environment is a very topical issue. We characterize particle's trajectory via an underdamped Langevin system driven by a Gaussian white noise with a time dependent…

Statistical Mechanics · Physics 2022-01-05 Yao Chen , Xudong Wang

Observations of pulsars across the radio spectrum are revealing a dependence of the characteristic scattering time ($\tau$) on frequency, which is more complex than the simple power law with a theoretically predicted power law index. In…

High Energy Astrophysical Phenomena · Physics 2021-02-04 Marisa Geyer , Aris Karastergiou