Increased depth of focus in random-phase-free holographic projection

Michał Makowski , Tomoyoshi Shimobaba , Tomoyoshi Ito

Abstract

The recently proposed random-phase-free method enables holographic reconstructions with very low noise, which allows fine projections without time integration of sub-holograms. Here, we describe the additional advantage of this method, namely, the extended depth of sharp imaging. It can be attributed to a lower effective aperture of the hologram section forming a given image point at the projection screen. We experimentally compare the depth of focus and imaging resolution for various defocusing parameters in the cases of the random-phase method and the random-phase-free method. Moreover, we discuss the influence of the effective aperture in the presence of local obstacles in the hologram's plane.