Non-destructive characterization of transparent armor layups

We have developed a material identification instrument, based on measuring the group refractive index dispersion curve using a low-coherence interferometer. Non-destructive product verification testing is critical for multilayer structures used in commercial or military applications. The ability to identify the number of layers in multilayer structures, the material composition of each layer, as well as the thickness of each layer non-destructively is important to ensure product quality in many fields, such as aerospace, defense, automotive and semiconductor. Low-coherence interferometry offers a quick and reliable way of obtaining material dispersion properties by measuring the spectral dependence of the optical thickness of the material. Latest advancements in the supercontinuum light generation have opened new opportunities for these highly accurate spectroscopic measurements. We have successfully applied the developed system to several known and unknown transparent layups.