Photoinduced birefringence photoelectronic-transport measurementsin congruent LiNbO3:Hf single crystals with different Hf concentration are presented The crystalline quality of the crystals is determined using microRaman spectroscopy Hf doping induces a progressive decrease of photoreftactive (PR) damage up to a threshold concentration of about 4 mol% Direct measurements of dark current, photoconductivity (PhC) and photovoltaic current demonstrate how such a decrease in PR-damage is correlated to a corresponding increase in PhC. Heating effects attributed to nonlinear absorption processes ate taken into account to interpretate results Hf-doping seems at least as effective as usual Mg-doping in reducing photoieftaction, requiring a lower dopant concentration The obtained results are relevant also because, among the known optical-damage-resistant impurities, Hafnium oxide is, up to now, the only additive used to create periodically-poled LN crystals by a direct-growth Czochtalski technique.
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