Image plane digital holography for simultaneous measurement of temporal and spatial coherence

Abstract

In this work, we propose and validate the Image Plane Digital Holography (IPDH) with laminar illumination technique for measuring the complete coherence degree, the temporal coherence length and the spatial coherence area (transversal coherence radius), of a light source at the same time and from a single measurement. This holographic technique has been used before as a fluid velocimetry technique that allows measuring the three components of the fluid velocity in a plane. Since its performance is limited by the temporal and spatial coherence of the laser, we can take advantage of this and make IPDH with laminar illumination a means of obtaining these laser properties. The proposed method could be of interest for the optics community since it could be used for any type of light source, presenting some advantages by comparing it with other well-established techniques. It has been tested by using a high repetition rate laser commonly used in velocimetry and the results have been compared to those obtained with other standard techniques, verifying the well-functioning of the IPDH-based technique.