We report simultaneous generation of multiple conical second-harmonic waves in a two-dimensional nonlinear photonic structure when illuminated by two overlapping noncollinear fundamental beams. We show that this phenomenon is caused by the nonlinear Čerenkov radiation emitted due to the interaction of photons from each constituent fundamental beam as well as the virtual one propagating along th...

We describe a spontaneous symmetry-breaking phenomenon between the intensities of the ordinary and extraordinary components of the fundamental field in intracavity type II harmonic generation. It is based on a triply resonant cavity containing a type II chi(2) crystal pumped at fundamental frequency omega0. The pump beam generates a second-harmonic mode at frequency 2omega0 that acts as a pump ...

A simple method is employed to investigate the nonlinear frequency conversion in optical superlattices (OSL) with pump depletion. Four rigorous phase-matching conditions for different purposes are obtained directly from the nonlinear coupled equations, and the resulting OSL domain structures are generally aperiodic rather than periodic. With this method, not only the intensity but also the phas...

Communicated June 30, 1964 The problem of the diffraction of obliquely incident scalar waves by finite slits and strips with various boundary conditions has been considered previously.' Reference may be made to the work of other authors on the diffraction of scalar waves by finite slits.2 The problem of the diffraction of obliquely incident vector elastic waves by a clamped finite strip has als...

We examine the influence of a random flow that occurs in the convection zone on frequencies of the solar acoustic oscillations. Using a perturbative method the dispersion relation is derived in the case of a random flow that is parallel to the wave propagation. This relation is subsequently solved numerically for various parameters of the random field to find the frequencies of the random acous...

This paper is concerned with problems of scattering of time-harmonic electromagnetic and acoustic waves from an infinite penetrable medium with a finite height modeled by the Helmholtz equation. On the lower boundary of the rough layer, the Neumann or generalized impedance boundary condition is imposed. The scattered field in the unbounded homogeneous medium is required to satisfy the upward an...

24 When a high harmonic is removed from a cosine-phase harmonic complex, we hear a 25 sine tone pop out of the perception; the sine tone has the pitch of the high harmonic while the 26 tone complex has the pitch of its fundamental frequency, f0. This phenomenon is commonly 27 referred to as Duifhuis Pitch (DP). This paper describes, for the first time, the cortical 28 representation of DP obser...

This paper is concerned with the inverse problem of scattering of time-harmonic elastic waves from rigid periodic structures. We establish the factorization method to identify an unknown diffraction grating profile (periodic surface) from knowledge of the scattered compressional or shear waves measured on a line above the periodic surface. Near-field operators are factorized by selecting approp...

Solitary waves in lattices, represented by homoclinic traveling wave trajectories of discrete dynamical systems, play a crucial role in many areas of science from condensed matter theory to biophysics [1]. In integrable systems solitary waves, known as solitons or quasiparticles, are understood rather thoroughly, with Toda lattice being the most prominent example that covers the whole range of ...

In the present work, treating the arteries as a thin-walled and prestressed elastic tube with a stenosis and the blood as a Newtonian fluid with negligible viscosity, we have studied the amplitude modulation of nonlinear waves in such a composite system by use of the reductive perturbation method. The governing evolution equation was obtained as the variable coefficient nonlinear Schrödinger (N...