Effect Of Tm Concentration On The Tunability Of The Ylf Laser In The 1.9 Mu M Region

We describe the continuous-wave (cw) operation of a LiYF4 laser based on crystals doped with different concentrations of Tm3+. We observed the fluorescence spectra from the upper laser level when the crystal is placed inside the laser resonator, in the same optical environment of the coherent emission. We measured the laser intensity as a function of pump power and obtained a 24% slope efficiency by selecting a suitable orientation of the crystal. Using all this information, we were able to demonstrate laser tunability at 1.9 mu m in a 50 cm(-1) wide interval