We demonstrate a nondestructive probing technique to investigate the inner crystal domain structure of ferroelectric crystals by analyzing the terahertz wave forms generated by optical rectification. Quantitative analysis of the domain structure has been performed for the domain width in periodically poled lithium niobate. Simulation results show that the terahertz wave form analysis reproduces...

This paper concerns a time-domain scattering problem of elastic plane wave by rigid obstacle, which is immersed in an open space filled with homogeneous and isotropic medium two dimensions. A new compressed coordinate transformation developed to reduce the into initial boundary value bounded domain over finite time interval. The well-posednesss established for reduced problem. adopts Galerkin m...

This tutorial describes mixed-domain wave-equation migration and migration velocity analysis techniques in a unified theoretical framework. I review two of the most general mixed-domain migration methods, Fourier finite-difference and generalized screen, and show how other commonly used wave-equation migration methods come about as special cases. I use the Born approximation to derive general e...

in this paper, an adaptive physics-based method is developed for solving wave motion problems in one dimension (i.e., wave propagation in strings, rods and beams). the solution of the problem includes two main parts. in the first part, after discretization of the domain, a physics-based method is developed considering the conservation of mass and the balance of momentum. in the second part, ada...

In this paper, a new algorithm for studying elastic wave propagation in the phononic crystals is presented. At first, the displacement-based forms of elastic wave equations are derived and then the forms are discretized using finite difference method. So the new algorithm is called the displacement-based finite difference time domain (DBFDTD). Three numerical examples are computed with this met...

This paper presents the preliminary results of an extensive parametric study on seismic response of two-dimensional semi-sine shaped hills to vertically propagating incident P- and SV-waves. Clear perspectives of the induced diffraction and amplification patterns are given by investigation of time-domain and frequency-domain responses. It is shown that site geometry, wave characteristics , and ...