THz Multi-Layer Imaging via Nonlinear Inverse Scattering

In this paper, we address the problem of mitigating nonlinear shadow effects in Terahertz time-domain spectroscopy (THz-TDS) multi-layer imaging. To that end, we utilize a one-dimensional (1D) nonlinear model to capture the interaction between the dielectric permittivity profile and the THz wavefield and recover the multi-layer structure by solving a 1D nonlinear inverse scattering via iterative and sequential optimization over frequencies. Numerical results confirm the effectiveness of the proposed method.