Non-Invasive Optoacoustic Imaging for In-Depth Cultural Heritage Diagnostics

Abstract

The complex composition of cultural heritage (CH) items presents significant challenges in assessing their condition and predicting potential risks of material degradation. Typically employed diagnostic optical methods are inevitably limited by light scattering, thus restricting in-depth investigations of objects with complex structural and optical properties. To address this issue, we introduce a novel reflection-mode optoacoustic (OA) diagnostic system for non-contact and non-invasive measurements of CH, placing emphasis on the detection of ageing-related modifications in artistic media such as paints. In this direction, the sensitivity of OA measurements was proven to be up to two orders of magnitude higher than conventional absorption spectroscopy assessments. Furthermore, we have evaluated the in-depth imaging capabilities of the developed OA system, demonstrating that it can offer superior contrast levels of sketches beneath opaque paint layers compared to standard near-infrared diagnostic techniques. The current OA imaging technology may advance state-of-the-art diagnostic capabilities in CH preservation by delivering unprecedented depth-to-resolution ratios combined with exceptional optical absorption sensitivity in a non-invasive manner. These features are crucial for the early detection of material degradation and the comprehensive analysis of CH objects, facilitating the development of optimal conservation strategies to prolong their lifespan and preserve their aesthetic value.

Keywords

• optoacoustic
• photoacoustic
• cultural heritage
• diagnosis
• imaging
• degradation