One-dimensional optical compression and backpropagation of particle digital in-line holograms

This work explores the possibility of using cylindrical lenses in digital in-line holography to reduce particle hologram imprint and cross-interference on the camera sensor. Experimental results on sprayed and levitated droplets, together with simulations using Rayleigh-Sommerfeld integrals and <i>ABCD</i> analysis, confirm the feasibility of this compression method for spherical particles. However, it turns out that, when using a back-propagation method to reconstruct the particle field, reducing the fill rate of the camera sensor does not in itself improve the quality of the particle field reconstruction. It is the asymmetric magnification of the optical system that enables this improvement, transforming the twin particle problem into a two half-twin particle problem. The latter have a less impact on the reconstruction process, allowing the statistics to be improved. This advantage increases with the magnification factor of the optical system. The authors believe that this optical method could be even more interesting for parametric inversion methods used for full volumetric reconstruction of particle fields.