The propagation of temporal solitary waves, formed in the second-order nonlinear medium, is analysed in waveguide directional couplers. The influence of the thirdorder nonlinearity on the switching effect is also presented. Recently, the great effort of nonlinear guided-wave phenomena research is focused on the cascaded second-order process which can produce relatively large intensity-dependent...

The Bödewadt boundary layer flow on the stationary bottom end wall of a finite rotating cylinder is very sensitive to perturbations and noise. Axisymmetric radial waves propagating inward have been observed experimentally and numerically before the appearance of spiral three-dimensional instabilities. In this study, the sensitivity and response of the finite Bödewadt flow to a harmonic modulati...

We analyze two-component spatial optical vortex solitons supported by parametric wave mixing processes in a nonlinear bulk medium. We study two distinct cases of such localized waves, namely, parametric vortex solitons due to phase-matched second-harmonic generation in an optical medium with competing quadratic and cubic nonlinear response, and vortex solitons in the presence of third-harmonic ...

Algorithms for ground vehicle classification using acoustic measurements often use features based on the relative amplitudes of harmonic components. The average power measured at each harmonic frequency fluctuates due to scattering of the acoustic waves during propagation and additive noise at the sensor. In this paper, we use propagation models for frequencydependent scattering of acoustic sig...

Nonlinear ultrasonic waves in solids have shown good sensitivity to quasi-static stresses. The stress sensitivity of elastic waves is typically associated to finite strains (e.g. theory of acoustoelasticity). In the case of waveguides, classical nonlinear theories for guided waves are still based on the assumption of finite strains. In the case of constrained solids subjected to thermal excursi...

We analyze the effect of phase-matched third-harmonic generation on the existence and stability of (1 1 1)-dimensional bright and dark spatial solitary waves in optical media with a cubic (or Kerr) nonlinear response. We demonstrate that parametric coupling of the fundamental beam with the third harmonic leads to the existence of two-color solitary waves resembling those in a x (2) medium and t...

HARMONIC IMAGING USING A MECHANICAL SECTOR, B-MODE ULTRASOUND SYSTEM by Danna Gurari ADVISOR: Dr. William D. Richard August 2005 Saint Louis Missouri An ultrasound imaging system includes transmitting ultrasound waves into a human body, collecting the reflections, manipulating the reflections, and then displaying them on computer screen as a grayscale image. The standard approach for ultrasound...

An experiment is described that investigates certain interference effects for second-harmonic generation within a resonant cavity. By employing a noncollinear geometry, the phases of two fundamental beams from a frequencystabilized dye laser can be controlled unrestricted by the boundary conditions imposed in an optical cavity containing a KDP crystal and resonant at the second harmonic. The fu...

A number of modes of oscillations of particles and fields can exist in space plasmas. Since the early 1970s, space missions have observed noise-like plasma waves near the geomagnetic equator known as 'equatorial noise'. Several theories were suggested, but clear observational evidence supported by realistic modelling has not been provided. Here we report on observations by the Cluster mission t...