Funktionale Grenzflächen

We present short time measurements to determine the distribution of fluorine dopant in extended fused silica samples. These measurements are based on pulsed Raman spectroscopy. Our investigations are starting point for a further development of a nondestructive optical in situ method of fluorine detection. A KrF excimer laser (248 nm) of narrow bandwidth was used to excite the vibrational transitions of Si–F (940 cm−1) and Si–O groups (809 cm−1). The fluorine concentration at a reference sample was determined by WDX-analysis to calibrate the intensity ratio of the Si–F and the Si–O vibrational bands. We investigated extended dry fused silica samples with a known fluorine concentration ≤10000 wt ppm. The detection limit amounts to 2000 wt ppm.