A diode-pumped 1.4-W Tm/sup 3+/:GdVO/sub 4/ microchip laser at 1.9 /spl mu/m

GdVO/sub 4/ as a host for thulium has several advantages for diode pumping in comparison with other crystals. The absorption cross section of thulium in GdVO/sub 4/ is considerably stronger and broader than in YAG and YLF, and the spectrum is shifted closer to the emission wavelength of commercially available AlGaAs laser diodes. In our paper, we report on a diode-pumped monolithic Tm/sup 3+/(6.9 at.%):GdVO/sub 4/ microchip laser at 1.9 /spl mu/m. A maximum output power of 1.4 W is achieved. Two different arrangements for cooling the crystal are discussed. Furthermore, the input-output curves under Ti:sapphire pumping are compared for different pump wavelengths. Slope efficiencies of 58%, clearly exceeding the Stokes limit of 41%, are achieved.