Diffraction-based modeling of high-numerical-aperture in-line lensless holograms

Abstract

Conventionally, for modeling in-line lensless holograms of systems with high numerical apertures and diverging spherical illumination, the samples are considered as an ensemble of secondary point sources. On following Huygens's principle, the in-line hologram is the result of the amplitude superposition of the secondary spherical wavefronts with the wavefront originated in the point source. Albeit simple, this approach limits the shapes of the objects that can be modeled and the computation time rises with the complexity of the sample. In this work, we present a diffraction-based approach to model in-line lensless holograms. Samples with any shape or size can be modeled for in-line holographic systems with numerical apertures up to 0.57. The method is successfully applied to model objects of intricate submicrometer structures and/or multiple samples lying within a unique sample volume.