Abstract:To investigate the damage mechanism of carbon fiber reinforced plastics ( CFRP) and monitor its manufacturing process quality, high-resolution non-destructive testing was conducted on the impact-damaged areas of CFRP. An all-optical non-contact photoacoustic microscopy ( AONC-PAM) imaging system was constructed, utilizing a self-developed dual-contrast imaging mode combining optical absorption with backscattering, for high-resolution non-destructive testing of CFRP′s damage areas under different impact energies. Experimental results showed that the spatial resolution of the AONC-PAM system was 2. 9 ± 0. 5 μm. The dualcontrast imaging strategy enabled acquisition of images based on optical absorption and surface scattering characteristics simultaneously, as well as their overlay, at a rate of 2 seconds per frame. The AONC-PAM system revealed more imaging details compared to the conventional brightfield microscopy system, including carbon fiber distribution and other microscopic defects such as fiber breaks and delamination, missing bundles, and wrinkles, with detectable defect sizes ranging 10 ~ 20 μm, facilitating precise quantification of damaged areas.