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Laser-Induced Damage in Optical Materials
(Brückner1997; Cannas et al. 2004). Other defect centers common for a-SiO
2
, for exam-
ple, a free valance at a silicon atom (E′-center) or nonbridging oxygen holes (NBOH),
have not been found.
In contrast to a-SiO
2
, UV/DUV laser–induced defect generation is not expected in
pure α-quartz because of the large binding energy of ideal Si–O bonds in the crystal
network and the lack of distorted, low-energy Si–O bonds responsible for laser-induced
absorption degradation in a-SiO
2
. erefore, it is assumed that the main origin for UV/
DUV absorption in α-quartz under laser irradiation is related to trace impur ...