A Magneto-Optic Based Flaw Imaging Technique for Underwater Applications

This was a Joint Industry Project (JIP). The purpose of this project was to demonstrate the possibility of developing a magneto-optic technique for direct visualization of flaws in ferrous materials in a marine environment. The technique is based on the property of certain magneto-optic garnel films to rotate the plane of polarization of an incident, linearly polarized light wave. This technique can be used in a hand-held device or operated by an automated submersible for the inspection of offshore structures. Because such a device can observe the magnetic anomalies of flaws through considerable thickness of biofouling, the technique does not require full clearing of surfaces before inspection.