Quantitative phase retrieval of the boundary diffraction wave emanated from a straight edge using a diffraction Lloyd mirror interferometer

Diffraction of light has long been of interest due to its relevance in explaining many physical phenomena. The boundary diffraction wave (BDW) approach, based on the scalar diffraction theory, provides a simplified formulation by requiring the evaluation of a line integral instead of surface integrals. Although the phase is a fundamental component of the propagated complex field, the phase behavior of the BDW has not been quantitatively investigated. This work presents a detailed quantitative experimental study of the BDW’s phase using a diffraction Lloyd’s mirror interferometer. The ability of this interferometer to generate fringes in both direct geometrical and shadow regions enables direct phase mapping of the BDW. The results reveal a continuous phase variation across both regions, demonstrating a uniform BDW behavior. The findings are further validated numerically and experimentally using a Mach–Zehnder interferometer.