PERFORMANCE OF A TM3-M((G)DVO(4) MICROCHIP LASER AT 1.9 MU)

GdVO4 as a host for thulium has several advantages for diode pumping. The absorption cross section of thulium in GdVO4 is considerably stron ger and broader than in YAG and YLF, and the spectrum is shifted close r to the emission wavelength of commercially available AlGaAs laser di odes. In our paper we compare the 2 mu m transition in Tm:GdVO4 with t he one in Tm:Ho:GdVO4. The population dynamics in the two crystals is discussed. Furthermore, we report on the optimisation of a Tm3+ (6.9 a t.%):GdVO4 microchip laser with respect to high efficiency. CW Iasing is established at room temperature in a wavelength range around 1.95 m u m. The lowest threshold achieved is 310 mW and the highest slope eff iciency is 21%. (C) 1998 Elsevier Science B.V. All rights reserved.