Growth and characterization of (Tm,Y)Al3(BO3)4 and (Yb,Y)Al3(BO3)4 crystals

New data relating to flux growth, composition, homogeneity and physical characteristics of (R,Y)Al3(BO3)4 (R=Tm or Yb) crystals are discussed. Single crystals have been obtained using K2Mo3O10-based fluxes by spontaneous nucleation as well as by the top-seeded solution growth at cooling rates of 4.8-12 °C/day and 0.2-5 °C/day, respectively, in the temperature range from 1120 to 900 °C. It is found that the average Tm and Yb segregation coefficients are close to unity, and vary from 0.80 to 1.02, as a consequence of minor difference in the sizes between Y3+ and R3+ cations. Two morphological types of (Tm,Y)Al3(BO3)4 crystals have been revealed. The average thermal expansion coefficients of Yb:YAB along a- and c-axis are measured as 2×10−6/K and 9.7×10−6/K, respectively, in the temperature range of 298-573 K. The specific heat of the Yb:YAB crystal at room temperature is found to be 0.76 J/g K, implying that this material can exhibit significant resistance to laser damage. Over 1.1 W of green emission has been obtained from a diode pumped 3×3×3 mm3 Yb:YAB crystal. The conversion efficiency of diode to green is 10%. High beam quality of green and IR emission can be easily attained due to the good crystal quality and lack of thermal effects.