Pile irradiation induced 4.4-eV photoluminescence in fused silica

In pile irradiated type-I fused silica, strong photoluminescence (PL) was o bserved at similar to 4.4eV. The PL band was successfully decomposed into t wo Gaussian spectra due to the pile-induced B-2 alpha band at 4.46 eV and d ue to the intrinsic B-2 beta band at 4.42 eV, respectively. In addition, st rong optical absorption (OA) was observed above similar to 4eV in these sam ples. The OA band was also decomposed into six Gaussian OA bands at 6.5, 5. 85, 5.53, 5.17, 5.06, and 4.86 eV. Besides, the PL band at 1.9 eV due to th e NBOHC was observed. The above results indicated that pile irradiation ind uced the B-2 alpha band by recoiling an oxygen atom, and the NBOHC and the E' center by the fission of the Si-O-Si bond.