Anomalous incident-angle and elliptical-polarization rotation of an elastically refracted P-wave

Abstract

We report a newly discovered anomalous incident-angle of an elastically refracted P-wave, arising from a P-wave impinging on an interface between two VTI media with strong anisotropy. This anomalous incident-angle is found to be located in the post-critical incident-angle region corresponding to a refracted P-wave. Invoking Snell’s law for a refracted P-wave provides two distinctive solutions before and after the anomalous incident-angle. For an inhomogeneously refracted and elliptically polarized P-wave at the anomalous incident-angle, its rotational direction experiences an acute variation, from left-hand elliptical to right-hand elliptical polarization. The new findings provide us an enhanced understanding of acoustical-wave scattering and lead potentially to widespread and novel applications.

Acoustic Waves at the Interface Between Different Types of Anisotropic-Strata

“…Now, consider an incident P-wave from VTI to TTI medium with an incident angle (θ). For the TTI medium, Bond transformation can be used to convert its tilt-angle structure to the same tensor form of the VTI structure [24][25][26][27][28][29][30][31][32][33][34]; Kelvin-Christoffel equation can be solved for the reflected and refracted coefficients;…”

“…It should be noted that the reflection and refraction coefficients are not smooth continuous at the angle of critical incidence. The polarization state of the refracted wave is also influenced by the tilting-angle and anisotropy of the refraction medium [29,31,40].…”

“…While an interface between likewise-media has a relatively simple geometric structure [24][25][26][27][28][29][30][31][32][33][34], the interface between unlike-media can be much more complicated [35].…”

Goos-Hänchen Effect: An Intriguing Phenomenon from Optics to Acoustics

“…Most of these reported works have been focused on phase shift. Two models have been reported on lateral displacement [35][36][37][38][39][40][41].…”