Artifact-free holographic light shaping through moving acousto-optic holograms

Abstract

Holographic light modulation is the most efcient method to shape laser light into well-defned patterns and is therefore the means of choice for many intensity demanding applications. During the last two decades, spatial light modulators based on liquid crystals prevailed among several technologies and became the standard tool to shape light holographically. But in the near future, this status might be challenged by acousto-optic defectors. These devices are well known for their excelling modulation rates and high optical power resilience. But only few scattered precedents exist that demonstrate their holographic capabilities, despite the many interesting properties that they provide. We implemented a holographic acousto-optic light modulation (HALM) system, that is based on displaying holograms on acousto-optic defectors. We found that this system can eliminate the ubiquitous coherent artifacts that arise in holography through the inherent motion of acoustooptic holograms. That distinguishes our approach from any other holographic modulation technique and allows to reconstruct intensity patterns of the highest fdelity. A mathematical description of this efect is presented and experimentally confrmed by reconstructing images holographically with unprecedented quality. Our results suggest that HALM promotes acousto-optic defectors from highly specialized devices to full-fedged spatial light modulators, that can compete in a multitude of applications with LC-SLMs. Especially applications that require large optical output powers, high modulation speeds or accurate gray-scale intensity patterns will proft from this technology. We foresee that HALM may play a major role in future laser projectors and displays, structured illumination microscopy, laser material processing and optical trapping.