Laser Speckle Photometry (LSP) - optical sensor system for monitoring of material condition and processing

The Fraunhofer IKTS at Dresden-Klotzsche develops innovative methods and testing systems for characterization of material properties and system components, product quality control and monitoring of manufacturing processes. The IKTS own the extensive know-how of laser-based measurement and testing methods, such as Raman, Fluorescence, Interferometry, Ellipsometry and the Laser Speckle Photometry (LSP). LSP was developed by the Fraunhofer-Gesellschaft completely and it has been successful tested in laboratory. Currently this optical method will be transferred to industrial applications. The Laser Speckle Photometry is a noncontact nondestructive testing method which bases on detection and analysis of thermal, mechanical or manufacturing process activated characteristic speckle dynamics. The determination of the material conditions state bases on understanding of structural changes on different scaling levels during the excitation of the frequency analysis of time resolved speckle fluctuation. The LSP determined rapid relevant material quality characteristics and detect defects. It allowing a complete online monitoring of production processes. In this work, the principle and first results for several materials, objects and applications will be shown. In addition we perform the LSP to obtain the speckle time response of ceramic material for microcrack detection. Even, it will be present the results of the development of a sensing system for determination of gold content of contacts manufactured by overlaying welding with the lateral dimensions <100 microns.