[摘要]:Laser experiments were performed on buried, ridge-type channel waveguides in an 8 at.% thulium-doped, yttrium-gadolinium-lutetium codoped monoclinic double tungstate. A maximum slope efficiency of 70% and output powers up to 300 mW about 2.0 mu m were obtained in a mirrorless laser resonator, by pumping with a Ti:sapphire laser near 800 nm. To the best of our knowledge, this result represents the most efficient 2 mu m channel waveguide laser to date. Lasing is obtained at various wavelengths between 1810 nm and 2037 nm. (C) 2012 Optical Society of America