Transparent and inclusion-free RE1−xLaxVO4 (RE=Gd, Y) single crystal fibers grown by LHPG technique

We describe in this work the growth of pure and Nd-doped transparent fibers of RE1−xLaxVO4 (RE=Gd, Y and x=0.2, 0.4 and 1.0) by the laser heated pedestal growth technique. The fibers obtained were in the range of 400-700 μm in diameter and up to 40 mm in length. Our crystalline fibers were free of black phases and microscopic inclusions. Temperature measurements on the molten zone surface showed that the liquid temperature suddenly dropped approximately 200 °C. This decrease in the liquid temperature is here associated with an self-adjustment of the melt composition during the fiber growth. Crystallographic data shows that the obtained fibers (x=0.2 and 0.4) belong to the I41/amd symmetry, with the exception of LaVO4 (x=1.0), which crystallized with P21/n symmetry. Optical absorption and lifetime measurements on Nd-doped fibers showed the same good optical properties as the Nd:YVO4 bulk crystals, with larger spectral linewidths which are desired for diode laser pumping.