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Laser-Induced Damage in Optical Materials
pumped by Nd:YAG lasers. However, its use in high optical power devices is limited due
to a photorefractive eect causing strong beam distortions at relatively weak intensi-
ties (150 W/cm
2
at 532nm [115]). A large number of articles can be found concerning
the photorefractive eect in LN (oen named “optical damage,” although the eect is
usually reversible).
In lithium niobate crystals, this phenomenon is mainly due to Fe impurities and Nb
Li
intrinsic defects (i.e., Nb
5+
in Li
+
sites, also called antisites) [24,40]. erefore, the pho-
torefractive threshold can be improved by decreasing the Fe co ...