US Patent 11397158 Reconfigurable laser stimulated lock-in thermography for micro-crack detection

Systems and methods for laser stimulated lock-in thermography (LLT) crack detection are provided. The system includes a spatial light modulator and a controller. The spatial light modulator reflects a laser beam to focus the laser beam onto a sample for detection of a crack, hole or scratch. The controller is coupled to the spatial light modulator and controls operation of the spatial light modulator to switch focus of the laser beam onto the sample between a plurality of LLT focus configurations for detection of the crack, hole or scratch on the sample. The method includes using a first one of the plurality of LLT configurations for coarse scanning of the sample to detect a crack, hole or scratch on the sample and, when a crack, hole or scratch is detected on the sample, switching to a second one of the plurality of LLT configurations for fine scanning of the crack, hole or scratch on the sample to determine one or more parameters of the crack, hole or scratch on the sample.