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Investigations to highlight the first stage of UV-fatigue effect in silica

The fatigue effect under multiple UV-laser irradiations can be attributed in many materials to a local material modification induced by the subsequent nanosecond laser pulses. Non-destructive investigations before breakdown are essential tools to study the mechanisms involved in the material modification process. In this work, we discuss the possibility to highlight the first stage of the material changes in UV-irradiated silica. Laser-induced material “defects” are studied by local in situ fluorescence measurements.