Crystal Growth and Spectroscopic Investigation of Yb,Er:$YCa_4O{(BO_3)}_3$ for 1.55$\mu m$ Laser

Single crystals of Yttrium Calcium Oxyborate (YCOB) doped with different concentrations of Er3+ and Yb3+ ions were growth by Czochralski method. High qualities of crystals in morphology and transparency were obtained . Analysis on crystal structure and lattice parameters were performed by X-ray diffraction method. It was found that congruent melting composition is YCA4.2O1.2(BO3)3. Absorption and fluorescence properties of grown crystals were also reported.