Agour, MostafaMostafaAgourFalldorf, ClaasClaasFalldorfTaleb, FatimaFatimaTalebKoch, MartinMartinKochBergmann, Ralf B.Ralf B.BergmannCastro-Camus, EnriqueEnriqueCastro-Camus2025-05-062025-05-062022-06-231539-4794https://media.suub.uni-bremen.de/handle/elib/895110.26092/elib/3830Terahertz (THz) radiation has shown enormous potential for non-destructive inspection in many contexts. Here, we present a method for imaging defects in chocolate bars that can be extended to many other materials. Our method requires only a continuous wave (CW) monochromatic source and detector at relatively low frequencies (280 GHz) corresponding to a relatively long wavelength of 1.1 mm. These components are used to construct a common-path configuration enabling the capturing of several images of THz radiation diffracted by the test object at different axial depths. The captured diffraction-rich images are used to constrain the associated phase retrieval problem enabling full access to the wave field, i.e., real amplitude and phase distributions. This allows full-field diffraction-limited phase-contrast imaging. Thus, we experimentally demonstrate the possibility of identifying contaminant particles with dimensions comparable to the wavelength.enAlle Rechte vorbehaltenAlle Rechte vorbehaltenphase-contrast imagingTerahertz radiationPhase Retrieval600Artikel/Aufsatzurn:nbn:de:gbv:46-elib89519