Extracting phase distortion from laser glints on a remote target using phase space plenoptic mapping

Abstract

Directed energy systems rely on the phase conjugation concept to focus laser beams remotely through turbulent environments. In application, a major problem exists where the beacon signal may be neither well defined upon generation nor free from speckle patterns in its vicinity. Such phenomena make it challenging to extract accurate phase information from the scene of a laser beacon and to direct a phase conjugated beam toward the target. In this work, we propose and demonstrate the use of a plenoptic sensor system that images the 4D phase space of multiple glints on a target. A phase retrieval algorithm is designed and applied to reveal the phase distortion from irregular glint patterns. The reconstruction results are verified through comparison with the phase retrieval from a well-defined beacon that alternates its on/off illumination in adjacent frames. As a result, we show that the multi-glint interference problem can be solved using the plenoptic sensor system, which further broadens the application scenarios for directed energy systems.