Abstract

The Sr_xBa_1−xNb₂O₆ (SBN, with x=0.6 in our case) is a ferroelectric crystal with a transition temperature near to room temperature and widely used as photorrefractive material. These two characteristics allow to easily develop periodic ferroelectric domain patterns, which can be used to generate laser harmonic radiation by quasi-phase matching (QPM). It has been previously reported that QPM also takes place in as grown crystals [1], due to the appearance of needlelike ferroelectric domains parallel to the c axis. Due to their natural origin, a relatively large distribution of domain sizes, around 3 µm in diameter, takes place, allowing for second harmonic generation in a wide range of wavelengths (1000-1175 nm). When SBN crystals are doped with Nd³⁺ ions, laser action is obtained with relatively low thresholds (50 mW in a simple end pumped semispherical laser cavity) under Ti:Sapphire pumping [2]. The saturation intensity factor is ~4-10²³ cm⁻²s⁻¹.

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