Caveats and pitfalls of high energy UV laser operation on ground

Kurzfassung

During the Aeolus laser and instrument transmitter development it was shown that atmosphere quality was one major limiting factor for high energy UV laser operation at ambient pressure. As already proven in literature operation can only be safely obtained in the presence of oxygen ([1] to [6]). Furthermore, air quality has to be adequately controlled and monitored to ensure that no catastrophic event occurs. On-line qualitative (no/no-go discriminator) can be obtained using fluorescence monitoring of the laser beam, while GC-MS remains the technique of choice to quantitatively evaluate suitability of air supply a priori. LIC testing is in the process of being adapted to trace contaminant evaluation. Finally, the formation of laser generated absorbing features is described, during air irradiation. The potential root causes of these absorbing dot-like features are explored, using optical measurements, microscopic inspections and chemical analysis. Current results indicate organic deposits associated with metallic particles and a presence of phosphates