Application of fluorescence microscopy for noninvasive detection of surface contamination and precursors to laser-induced damage.

We present an experimental investigation to evaluate fluorescence microscopy as a tool to detect surface contamination as well as reveal surface damage precursors on optical components for large-aperture laser systems. We performed fluorescence imaging experiments using 351-nm laser excitation, whereas in situ damage testing was performed at laser fluences well below the dielectric breakdown threshold of the pure material. The experimental results demonstrated the potential of this technique to address both aforementioned technical issues.