Brillouin scattering in optical fibres is a fundamental interaction between light and sound with important implications ranging from optical sensors to slow and fast light. In usual optical fibres, light both excites and feels shear and longitudinal bulk elastic waves, giving rise to forward-guided acoustic wave Brillouin scattering and backward-stimulated Brillouin scattering. In a subwaveleng...

Abstract: Since soil dynamic behaviour is nonlinear in nature therefore a nonlinear viscoelastic model for isotropic materials is proposed in this study. This model is a combination of inelasticity and nonlinear damping. In this model, the shear modulus is taken as a function of the excitation level. The viscosity is assumed to vary nonlinearly. The validity of this model is checked for low amp...

local site conditions have a strong effect on ground response during earthquakes. two important soil parameters that control the amplification effects of seismic motions by a soil column are the soil hysteretic damping ratio and shear wave velocity. this paper presents the results of in situ damping ratio measurements performed using continuous surface wave attenuation data at a site in semnan ...

The results of NDE and material characterization with mode conversion of air-coupled ultrasound into plate and surface waves in solids are reported. Singleand both-sided configurations of efficient slanted wave conversion are developed and tested for various materials. An alternative option is based on the excitation of cylindrical plate and surface waves by a focused air-coupled beam incident ...

Nonlinear differential equations are known to describe a wide variety of phenomena not only in physics, in which applications extend over magnetofluid dynamics, water surface gravity waves, electromagnetic radiation reactions, and ion acoustic waves in plasmas, just to name a few, but also in biology and chemistry. It is one of the important tasks in the study of nonlinear differential equation...

It is shown that the Maxwell's equations for surface electromagnetic TM waves, propagating along the plane boundary between two nonlinear dielectrics with arbitrary diagonal tensor of dielectric permittivity, depending on |E|, can be integrated in quadratures.

The nolinear hydrodynamic equations of the surface of a liquid drop are shown to be directly connected to Korteweg de Vries (KdV, MKdV) systems, giving traveling solutions that are cnoidal waves. They generate multiscale patterns ranging from small harmonic oscillations (linearized model), to nonlinear oscillations, up through solitary waves. These non-axis-symmetric localized shapes are also d...

We employ noncontact optical techniques to generate and measure stress waves in uncompressed, one-dimensional microscopic granular chains, and support our experiments with discrete numerical simulations. We show that the wave propagation through dry particles (150 μm radius) is highly nonlinear and it is significantly influenced by the presence of defects (e.g., surface roughness, interparticle...

Interacting surface waves, parametrically excited by two commensurate frequencies (Faraday waves), yield a rich family of nonlinear states, which result from a variety of three-wave resonant interactions. By perturbing the system with a third frequency, we selectively favor different nonlinear wave interactions. Where quadratic nonlinearities are dominant, the only observed patterns correspond ...