Spectroscopic properties and laser performances of Yb : YCOB and potentialof the Yb : LaCOB material

In order to increase the compacity of the Yb-doped lasers, YCOB (Ca4Y(BO3)( 3)) materials with high ytterbium concentration have been characterized. La rge 15 at.% and 35 at.% ytterbium-doped single crystals were grown by the C zochralski pulling method. Spectroscopic and laser properties have been inv estigated and laser tests performed under titanium sapphire and diode pumpi ng at 976 nm, Low thresholds under Ti:Sa pumping (50 mW) and high slope eff iciency under diode pumping (66%) have been obtained. The optical quality a nd the distribution of Yb3+ dopant through the highly doped crystals is dis cussed. First results on the Yb:LaCOB crystals grown by the Czochralski pro cess, containing 46Yb(3+) at.%, are also presented. (C) 2001 Published by E lsevier Science B.V.