Tunable continuous wave and femtosecond mode-locked Yb3+ laser operation in NaLu(WO4)2

7 pages, 13 figures, 3 tables.-- PACS: 42.55.Rz; 42.60.By; 42.60.FcContinuous wave and femtosecond mode-locked laser operation of Yb3+ in the tetragonal NaLu(WO4)2 crystal host is demonstrated by pumping with a Ti:sapphire laser. Pumping with 1.8 W at 974 nm, a maximum output power of 650 mW was achieved at 1029.6 nm. The slope efficiency was in excess of 60%. The laser performance was similar for the two polarizations. By inserting a birefringent filter the output wavelength was tunable from 1010 to 1055 nm. Pulses as short as 90 fs with an average power of 50 mW were generated by passive mode locking at a repetition rate of 95 MHz. These attractive laser properties of NaLu1−xYbx(WO4)2 are related to the inhomogeneous broadening of the Yb3+ spectral features resulting from the local disorder of the host crystal. We report the spectroscopic properties of Yb3+ in the 5–300 K temperature range and the optical properties of the host at room temperature.This work was supported by Projects Nos. NMP3-CT- 2003-505580 (EU), MAT2004-21113E, and MAT2005-6354- C03-01 (Spain). A.G. (FPU2003-018), X.H. (JC12006-4015-2459) and X.M. (EX2004-1294) are supported by grants from the Spanish government. X.M. additionally acknowledges support from the European Science Foundation.Peer reviewe

Tunable continuous wave and femtosecond mode-locked Yb3+ laser operation in NaLu(WO4)2

7 pages, 13 figures, 3 tables.-- PACS: 42.55.Rz; 42.60.By; 42.60.FcContinuous wave and femtosecond mode-locked laser operation of Yb3+ in the tetragonal NaLu(WO4)2 crystal host is demonstrated by pumping with a Ti:sapphire laser. Pumping with 1.8 W at 974 nm, a maximum output power of 650 mW was achieved at 1029.6 nm. The slope efficiency was in excess of 60%. The laser performance was similar for the two polarizations. By inserting a birefringent filter the output wavelength was tunable from 1010 to 1055 nm. Pulses as short as 90 fs with an average power of 50 mW were generated by passive mode locking at a repetition rate of 95 MHz. These attractive laser properties of NaLu1−xYbx(WO4)2 are related to the inhomogeneous broadening of the Yb3+ spectral features resulting from the local disorder of the host crystal. We report the spectroscopic properties of Yb3+ in the 5–300 K temperature range and the optical properties of the host at room temperature.This work was supported by Projects Nos. NMP3-CT- 2003-505580 (EU), MAT2004-21113E, and MAT2005-6354- C03-01 (Spain). A.G. (FPU2003-018), X.H. (JC12006-4015-2459) and X.M. (EX2004-1294) are supported by grants from the Spanish government. X.M. additionally acknowledges support from the European Science Foundation.Peer reviewe

Spectroscopy and efficient laser operation near 1.95 μm of Tm3+ in disordered NaLu(WO4)2

Continuous wave and tunable laser operation at room temperature is demonstrated with single crystals of Tm-doped NaLu(WO4)2. Under Ti:sapphire laser pumping and tuning by an intracavity Lyot filter, the Tm3+ emission extended from 1799 to 2026 nm. The maximum output power exceeded 0.5 W and the maximum slope efficiency with respect to the absorbed power was above 58%. These good laser properties are related to the locally disordered tetragonal (I-4) structure of the crystalline host. Using low temperature spectroscopy and energy level simulation methods, the energy levels and spectroscopic properties of Tm3+ have been shown to be compatible with the S4 site symmetry. This allowed the reliable determination of the emission cross sections related to the laser transitions.This work was supported by Project No. MAT2005-6354-C03-01 (Spain). J. M. Cano-Torres, X. Han, and M. Rico were supported by the Spanish Science and Education Ministry through I3P-BPD2005, Juan de la Cierva, and Ramón y Cajal grants, respectively.Peer reviewe