Spatial frequency modulation imaging for laser processing applications

Single element detection, spatial frequency modulation imaging (SPIFI) is deployed in a laser processing environment. SPIFI images are used to monitor a laser melting process, like that encountered during additive manufacturing, with an exposure time of $120\mu s$, which enables real-time, in-situ monitoring of melt track formation coaxial with the processing laser. SPIFI images from a single photodiode are shown to be comparable to or better than white light camera images taken at the same numerical aperture. SPIFI deployed in this manner represents a disruptive new sensor metrology system that, when coupled with developing process models, can ultimately be used to validate statistically significant process parameter-signature-quality relationships with quantified uncertainty.