Holographic imaging of side-scattering particles

An off-axis holographic system in the side-scattering mode has been studied, and the requirements of fringe resolution and film sensitivity associated with holographic imaging of side-scattering particles analysed. By assuming the Mie scattering model, the fringe distribution about the y-axis (perpendicular to the plane of incidence of the reference light) was found to be asymmetrical, with unevenly distributed spacing, that is narrower in one x direction but greater in the side that is close to the origin. It was demonstrated that commercially available holographic film was sufficient to resolve the fringe frequency over the entire area of the holographic plate, at alpha less than or equal to 60 degrees for z=120 mm, and that images of particles as small as 20 mu m could be recorded. Astigmatism was found to occur and be responsible for the distortions of the particle images. Copyright (C) 1996 Elsevier Science Ltd.