Photoconductive and electro-optical Properties of Hf-doped Lithium Niobate Crystals

The optical and electrical properties of a set of Hf doped Lithium Niobate crystals with doping level from 2 to 8 mol % are reported. The photoconductivity is found to increase remarkably for Hf concentration equal and above 4 mol %. In contrast, the electro-optical coefficients keep almost constant with the crystal structural properties preserved. The conclusion is drawn that the decrease of the photorefractive response in Hf doped Lithium Niobate recently observed by other authors is mainly related to the increased photoconductivity

The structure of defects and its link with photorefractive properties in doped LiNbO3

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Photorefractivity of Hafnium-doped congruent lithium-niobate crystals

Transient and steady-state measurements of photoinduced birefringence in Hf-doped congruent lithium–niobate crystals are presented. Through a systematic investigation of crystals with different dopant concentrations, we find that Hf doping induces a progressive decrease of photorefraction up to a threshold concentration of about 4 mol %. Such a decrease is correlated to a corresponding increase in photoconductivity. The interpretation of measurements has to take into account heating effects that may be attributed to nonlinear absorption processes

Linear and nonlinear optical properties of Hafnium-doped lithium-niobate crystals

Abstract: Measurements of birefringence, second-harmonic phase-matching conditions, and nonlinear coefficient d(31) are performed for a set of Hafnium-doped congruent lithium niobate ( Hf:cLN) crystals as functions of dopant concentration. The data highlight that the threshold concentration, above which there is a change in the Hf incorporation mechanism, is slightly above 2mol% and that, up to this value of concentration, the efficiency of nonlinear processes is not affected by the dopant insertion. Combining these results with those already present in literature, Hf: cLN crystals appear to be very promising candidates for the development of photorefractivity-free wavelength converters working at room temperature