LASER OPERATION AND SPECTROSCOPY OF TM-HO-GDVO4

Laser operation on the Ho 5I7-5I8 2 mum transition in Tm:Ho:GdVO4 is d escribed, to our knowledge for the first time. This material has very strong and broad absorption bands, alpha = 19.1 cm-1 at 797 nm with a fwhm of 7 nm, which is very desirable for diode pumping. The fluoresce nce spectrum is continuous from 1.9 to 2.07 mum with two closely space d peaks at 2.04 and 2.05 mum. A 0.7 mm long Tm:Ho:GdVO4 sample was pum ped by a titanium sapphire laser using the active mirror geometry to a chieve 90% pump absorption efficiency. Room temperature lasing was ach ieved at 2.049 mum.