Abstract

Gadolinium scandium gallium garnet codoped with Nd and Or (GSGG:Nd,Cr) is the laser material with the highest measured efficiency. Thus it has great promise for use in laser systems where efficiency, power, and beam quality are desired. As part of a program on developing slab lasers with multikilowatt outputs, we are growing 5-in. diam GSGG:Nd,Cr boules, from which we will cut 10- × 20- × 1-cm³ slabs. Our efforts have focused on using the Czochralski growth technique, which has proved successful in growing commercially large GGG. We constructed a station that we modified to incorporate a 9-in. diam by 9-in. deep iridium crucible. The melt charge is 50 kg and we pull ~35-40% of the melt. In this system we have pulled 5-in. diam undoped GGG, undoped GSGG, and codoped GSGG. In the course of this effort we have solved a spiral growth morphological problem by using calcium additions to the melt. However, to prevent forming Cr⁴⁺, which is a 1-μm absorber, we are employing the Ce³⁺-Ce⁴⁺ couple to compensate for the Ca% We present data on boule quality: birefringence, wavefront distortion, and absorption losses

© 1986 Optical Society of America