Overview of the laser and non-linear optical properties of calcium-gadolinium-oxo-borate Ca4GdO(BO3)3

Ca4GdO(BO3)(3) (GdCOB) is a new non-linear optical (NLO) material which presents a congruent melting and can be grown from the melt in large size crystals (phi=50 mm, L=120 mm) using the Czochralski pulling method. This paper describes the crystal growth and NLO properties of GdCOB which compare favorably with those of commercial berates like BBO or LBO. Particular emphasis will be put on SHG of the Nd:YAG 1.064 mu m laser emission. Large amounts of Nd or Yb ions can be substituted for Gd in this material and Ln:GdCOB with Ln=Nd, Yb exhibits interesting laser properties, especially in the case of diode pumped Yb activated crystals. Finally by combining the NLO properties of the GdCOB matrix and the laser emission associated with the active ion, a green self frequency-doubling laser is obtained. In this field, Nd:GdCOB appears the most promising material for practical applications, able to generate visible green laser light with only one single crystal instead of two, as usually. To date an Nd:GdCOB crystal yields 114 mW at 530.5 nm (for 1250 mW of absorbed pump power), when pumped with a 2 TY high brightness laser diode. (C) 2000 Published by Elsevier Science S.A. All rights reserved.