Growth and characterization of a LaCa4O(BO3)3 crystal

The non-linear optical (NLO) crystal LaCa4 O(BO3)3 (LaCOB ) has been grown by the Czochralski method. X-ray diffraction experiments show that LaCOB crystal possesses the space group Cm, and its unit cell constants have been measured to be a=0.8168(3) nm,b=1.6081(7) nm and c=0.3630(6) nm, with an angle β=101.39°. The thermal properties of LaCOB have been studied; the specific heat of the crystal is 321.9 J/mol K at 330 K, and the three principal coefficients of thermal expansion of the principal axes have been calculated from the measured data to be 5.61×10-6 K-1, 7.21×10-6 K-1 and 11.01×10-6 K-1, respectively. The transmission spectrum shows that LaCOB crystal has a wide transparency wavelength range, and may be used as a NLO crystal.