Phase Imaging Through Scattering Media Based on a THz Airy Beam

In recent years, nondiffracting beams such as Airy beams and Bessel beams have garnered widespread attention due to their unique propagation characteristics. Among them, Airy beams exhibit exceptional imaging capabilities, including enhanced resolution, increased penetration depth, and improved contrast in complicated scattering environments. While research works on amplitude imaging with Airy beams has been extensive, the potential of Airy beams in phase imaging remains largely underexplored. This article proposes an Airy-beam-based through-scattering-media phase imaging technique in the THz band, which is referred to as Airy beam phase imaging (ABPI) technique. We design dielectric lenses to generate a THz Airy beam working from 190 to 210 GHz and investigate the imaging of some printed dielectric samples. We make scattering layers by glass beads to test the ABPI technique. We perform imaging experiments and have the following findings. First, the phase images obtained by the ABPI method bear much higher quality than the amplitude images. Second, the images reconstructed using broadband information outperform the single-frequency images. Third, the thickness of the dielectric samples can be estimated with high accuracy and three-dimensional (3-D) images of the samples can be reconstructed. Furthermore, the advantages of the ABPI technique are more obvious when scattering media is present in the propagation path of the Airy beam. This work provides a novel paradigm for accurate imaging of dielectric samples involving scattering media in the THz regime and paves the way for advanced 3-D imaging applications in nondestructive examination, biomedical imaging, food inspection, and security screening.