Widefield NV-Center Quantum Sensing for Non-Destructive Materials Testing

Most non-destructive testing methods are designed for relatively large construction parts and offer a relatively poor spatial resolution. However, due to progressing miniaturization, material properties on small scales become increasingly relevant. Atomically small quantum sensors, such as the Nitrogen-vacancy center in diamond, open doors to completely new sensing approaches offering a high potential to revolutionize non-destructive testing on small scales. This work assesses the applicability of widefield Nitrogen-vacancy center magnetic imaging to non-destructive testing. Based on a thin layer of Nitrogen-vacancy centers, the approach allows for rapid quantum sensing with a large field of view and a diffraction limited spatial resolution. Clear changes of the magnetic stray field distribution could be detected after a material sample underwent cyclic loading. The technique is suited to detect early stages of fatigue damage, but also to gain a better understanding of fatigue mechanisms on small scales. Furthermore, cracks and intermetallic phases in non-magnetic materials could be successfully detected underlining the potential for various non-destructive testing applications.