NEODYMIUM-ACTIVATED CA4GDB3O10 (ND-GDCOB) - A MULTIFUNCTIONAL MATERIAL EXHIBITING BOTH LASER AND NONLINEAR-OPTICAL PROPERTIES

Gadolinium calcium oxoborate GdCOB is a new nonlinear optical crystal that melts congruently and can be grown from the melt. Large-sized sin gle crystals phi similar to 25 mm, length similar to 100 mm with good optical quality are obtained using the Czochralski technique. GdCOB ap pears particularly interesting for second harmonic generation of the N d :YAG laser beam at 1.06 mu m. In such a process, efficiency higher t han 50% is obtained. Partial substitution of Gd3+ ions by Nd3+ leads t o the laser material Nd : GdCOB. Neodymium ions do not affect the crys tal quality and cw laser action is observed along the three crystallop hysic axes. A laser slope efficiency of 45% is obtained with the pump beam (Ti : sapphire laser tuned to 811 nm) along the Y crystallophysic axis. Self-frequency doubling of the Nd3+ laser emission is observed when the laser beam occurs in a direction perpendicular to Z and at 46 degrees from X. In preliminary experiments, 17 mW of green (530.5 nm) coherent beam are obtained for 800 mW of incident power. This corresp onds to an efficiency of 2.1%.