Nd: Bi4Ge3O12 crystal growth by czochralski method

Nd-doped Bi4Ge3O12 (Nd:BGO) crystals were successfully grown in the auto-diameter control system equipped with a frequency weighing sensor with the Czochralski method. The Nd3+ ion doping level was varied from 0.25 to 2.5 at.%. The crystals were transparent and of light purple color, with a typical size of about 20 mm in diameter and 50 mm in length. The effective distribution coefficient (keff) of Nd3+ ion was about 0.957 irrespective of concentration, and the Nd3+ ions were distributed homogeneously throughout the crystal. The doping concentration (pi) of active ion in Nd:BGO crystal was 2.54x1020 ions/cm3, which is higher than that in the Nd:YAG crystal. Therefore, the Nd:BGO crystal was judged to be more suitable for the laser diode pumping microchip laser material where size reduction was desirable.