Detection of Defects in Multilayer Dielectric Coatings Using Ultraviolet Fluorescence Microscopy

The inset shows a dielectric material monolayer and a network of absorbing defect structures formed inside the layer.  The image was captured using the ultraviolet fluorescence microscope developed in-house by Research Engineer Brittany Hoffman and Distinguished Scientist & Optical Materials Technology Group Leader, Stavros Demos. Such absorbing structures are believed to lower the laser-induced–damage performance of optical components (such as mirrors) used in high-power laser systems including the OMEGA and OMEGA EP lasers at LLE. Understanding the defects’ distributions and how to control them is critical for the developing optical components that exhibit higher resistance to laser damage and, ultimately, increase the power output of such systems.