PULSED-LASER-INDUCED DARK TRACES IN LINBO3-ZN AND LINBO3-MG

Laser-induced dark traces in LiNbO3:Zn (7.5 mol.%) and LiNbO3:Mg (6.5 mol.%) crystals have been studied with the crystals as the component f or 1064-532-nm second-harmonic generation of Nd:YAG radiation operatin g in a pulsed mode. The results show that, at high input power density , both crystals suffer from dark traces, which reduce the second-harmo nic-generation efficiency. The dark traces are induced by the 532-nm r adiation and can be recovered after the laser beam is shut off. The tr ansmission loss spectra show a broad absorption peak near 400 nm.