Irradiation Effects of Swift Heavy Ions Detected by Refractive Index Depth Profiling

Abstract

Evolution of depth profiles of the refractive index in Y3Al5O12 (YAG) crystals were studied under 200 MeV 136Xe14+ ion irradiation, since the index can be related with the stress change and/or the defect formation by the irradiation. Using the prism-coupling and the end-surface coupling methods, various waveguide (WG) modes were detected. Then, the index depth profiles were determined by reproducing the observed WG modes. The index changes were observed at three different depth regions; (i) a sharp dip at 13 μm in depth, which is attributed to the nuclear stopping Sn peak, (ii) a plateau near the surface between 0 and 3 μm in depth, which can be ascribed to the electronic stopping Se, since Se has a very broad peak at the surface, and (iii) a broad peak at 6 μm in depth. Since the last peak is ascribed to neither of Se nor Sn peak, it could be attributed to the synergy effect of Se and Sn.