Wide-field three-dimensional photoacoustic remote sensing microscopy for industrial non-destructive testing based on...

Photoacoustic remote sensing (PARS) microscopy has emerged as a promising non-contact technique for non-destructive testing (NDT). Wide-field imaging is highly desirable for comprehensive NDT analysis. However, previously reported scanning strategies have either been restricted to small imaging areas or achieved wide-field coverage at the expense of noticeable stitching artifacts. In this work, we present a PARS microscopy system incorporating a voice coil motor, capable of scanning a wide-field area of 2 × 2 cm² in under 6 minutes. To the best of our knowledge, this represents the largest field of view reported for PARS microscopy to date. The depth-resolving capability of the system is further validated by acquiring lateral scans at multiple depths, enabling three-dimensional (3D) visualization of both a 3D-printed stainless-steel sample and leaf veins. Moreover, the system is demonstrated for material differentiation by imaging a gold-coated silicon wafer and for surface roughness estimation through characterization of sandpaper of varying grit sizes, highlighting its potential for diverse NDT applications.