Camera-in-the-Loop Optimization for High-Fidelity Far-Field Holography with SLMs

Abstract

Spatial light modulators (SLMs) play a central role in high-precision beam shaping for applications such as holographic projection, microscopy, and laser material processing, where optical quality critically determines system performance. Robust calibration of SLM-based systems is therefore a prerequisite for reliable operation. Camera-in-the-loop calibration provides an experimentally efficient means of characterizing the full optical system without requiring separate measurements of individual aberrations. In this work, we employ a camera-in-the-loop approach to calibrate a phase-only SLM used in a far-field holographic projection setup. The resulting digital twin accurately reproduces experimentally recorded sensor images, including fine speckle features. Calibration fidelity is validated by comparing key system parameters against independent reference measurements. Using the calibrated model, we extend the hologram design process with a speckle suppression strategy and experimentally demonstrate far-field intensity distributions with significantly reduced speckle.