Uniqueness for phaseless inverse elastic scattering problem for periodic structures
Youzi He, Wei Wu, Hongyi Dang
TL;DR
The paper addresses the problem of uniqueness in phaseless inverse elastic scattering from periodic structures in two and three dimensions. It advances the theory by deriving explicit quasi-periodic/biperiodic Green's functions for the Lamé system, establishing reciprocity relations for point sources, scattered and total fields, and obtaining Rayleigh-type expansions in 3D. Using these tools, the authors prove uniqueness results for reconstructing periodic boundary surfaces from intensity-only near-field data, applicable to both 2D and 3D periodic and biperiodic geometries. The work provides novel mathematical constructs (Green's functions and Rayleigh expansions) and foundational uniqueness results that support phaseless reconstruction in periodic elastic media and can inform future algorithm development.
Abstract
This paper establishes uniqueness results of inverse elastic scattering problem with phaseless near-field data in periodic structures in $\mathbb{R}^2$ and periodic/biperiodic structures in $\mathbb{R}^3$. We use a superposition of two point sources in each periodic unit with different positions as the incident field, and measures the phaseless near-field data on a line parallel to $x_1$-axis in 2D, or on a plane parallel to $(x_1,x_2)$-plane in 3D. We first calculate the explicit formula of quasi-periodic/biperiodic Green's functions of Lamé system in $\mathbb{R}^3$. Then, to establish the uniqueness results, the reciprocity relations for point sources, scattered fields, and total fields are derived. Finally, with the help of Rayleigh's expansion, the uniqueness results are proved. The quasi-periodic/biperiodic Green's functions of Lamé system in $\mathbb{R}^3$, the reciprocity relations, and Rayleigh's expansion in $\mathbb{R}^3$ are novel results as important by-products in the proof process.
