Light-in-flight holography for visualization and velocimetry in three-dimensional flows

Abstract

Flow visualization and particle image velocimetry of deep volumes are achieved by holographic recordings. Light-in-flight holography is applied to avoid noise from out-of-focus regions during interrogation of the reconstructed image by use of a ruby laser source of small coherence. The scheme permits reconstruction of thin layers in depth without disturbance by the rest of the field. The location of the layers is selected by the position of a reconstructing slit aperture on the hologram. Applications to tracer particles in water and visualization by smoke of an air flow are given.