Advances in Optical Metrology: High Bandwidth Digital Holography for Transparent Object Analysis

Accurate and non-invasive optical metrology of transparent objects is essential in a wide range of scientific and industrial applications, from fluid dynamics to biomedical imaging. In this work, a digital holography approach for temperature mapping is presented that leverages a double field of view (FOV) configuration combined with high spatial bandwidth utilization (SBU). By capturing a multiplexed hologram from two distinct objects in a single-shot, the system overcomes the limitations inherent to single-view holography, enabling a more comprehensive object information of temperature-induced refractive index variations. The method integrates double FOV digital holography with high SBU, allowing for the accurate surface profiling and mapping of complex optical path length changes caused by temperature gradients. The technique exhibits strong potential for applications in glass industry and microfluidic thermometry, convection analysis, and combustion diagnostics, where precise thermal field measurements are crucial. Overall, this study introduces an efficient holographic framework that advances the capabilities of non-contact measurement applications by integrating double FOV acquisition in a single-shot with enhanced spatial bandwidth exploitation. The approach sets the groundwork for real-time, volumetric thermal imaging and expanding the applicability of digital holography in both research and industrial settings.