The impurity study of MRF processed fused silica surface

Abstract

MRF (magnetorheological finishing) will leave impurities and affect the LIDT (laser induced damage threshold) performance of fused silica components. This manuscript first measured the impurity distribution after MRF. Then three-dimensional FDTD (finite-difference time-domain) simulation was employed to study the light field distribution of impurities under laser irradiation and the relationship between the dielectric constant, the size of the impurities and LIEF (light intensity enhancement factor). At last the HF etching was verified to remove the impurities. Studies have shown that carbonyl iron and cerium oxide impurities exist after MRF. FDTD simulation showed for impurities of the same size, the LIEF value first decreases and then increases with the dielectric constant; while for impurities of the same dielectric constant, the LIEF value increases as the size increases. Finally, HF etching can effectively remove impurities on MRF processed fused silica components.