María Dolores Serrano

Tunable laser operation of ytterbium in disordered single crystals of Yb:NaGd(WO4)2.

Lasing of Yb3+ in a disordered single crystal host, NaGd(WO4)2, is reported. Pump efficiencies as high as 20% and slope efficiencies as high as 30% are achieved for both sigma- and pi-polarizations with Ti:sapphire laser pumping. The emission of Yb:NaGd(WO4)2 is centered near 1030 nm. Tunability between 1016 and 1049 nm is obtained with a Lyot filter.

Continuous-wave laser operation of Tm and Ho co-doped NaY(WO 4 ) 2 and NaLu(WO 4 ) 2 crystals

Tetragonal single crystals of NaT(WO(4))(2) (T = Y or Lu) co-doped with Tm(3+) and Ho(3+) ions have been employed for broadly tunable and efficient room-temperature laser operation at around 2 mum. With Ti:sapphire laser pumping at 795 nm, a slope efficiency and a maximum output power as high as 48% and 265 mW, respectively, have been achieved at 2050 nm from a Tm,Ho:NaY(WO(4))(2) crystal. Tuning from 1830 nm to 2080 nm has also been obtained using an intracavity Lyot filter.

Sub-80 fs pulses from a mode-locked Yb:NaGd(WO/sub 4/)/sub 2/ laser

In the paper passive mode-locking of the disordered laser crystal Yb:NaGdW using a semiconductor saturable absorber mirror (SAM), is demonstrated. The pulse durations as short as 75 fs were achieved in an initial experiment on mode-locking of disordered Yb:NaGdW.

Thermal Characterization, Crystal Field Analysis and In-Band Pumped Laser Performance of Er Doped NaY(WO4)2 Disordered Laser Crystals

Undoped and Er-doped NaY(WO4)2 disordered single crystals have been grown by the Czochralski technique. The specific heat and thermal conductivity (κ) of these crystals have been characterized from Tu200a=u200a4 K to 700 K and 360 K, respectively. It is shown that κ exhibits anisotropy characteristic of single crystals as well as a κ(T) behavior observed in glasses, with a saturation mean free phonon path of 3.6 Å and 4.5 Å for propagation along a and c crystal axes, respectively. The relative energy positions and irreducible representations of Stark Er3+ levels up to 4G7/2 multiplet have been determined by the combination of experimental low (<10 K) temperature optical absorption and photoluminescence measurements and simulations with a single-electron Hamiltonian including both free-ion and crystal field interactions. Absorption, emission and gain cross sections of the 4I13/2↔4I15/2 laser related transition have been determined at 77 K. The 4I13/2 Er3+ lifetime (τ) was measured in the temperature range of 77–300 K, and was found to change from τ (77K) ≈ 4.5 ms to τ (300K) ≈ 3.5 ms. Laser operation is demonstrated at 77 K and 300 K by resonantly pumping the 4I13/2 multiplet at λ≈1500 nm with a broadband (FWHM≈20 nm) diode laser source perfectly matching the 77 K crystal 4I15/2 → 4I13/2 absorption profile. At 77 K as much as 5.5 W of output power were obtained in π-polarized configuration with a slope efficiency versus absorbed pump power of 57%, the free running laser wavelength in air was λ≈1611 nm with the laser output bandwidth of 3.5 nm. The laser emission was tunable over 30.7 nm, from 1590.7 nm to 1621.4 nm, for the same π-polarized configuration.

Tunable, Continuous-Wave near 2-μm Laser Operation of Tm 3+ in NaY(WO 4 ) 2 Single Crystal

Broadly tunable (1847-2069 nm) continuous-wave laser operation of 4.68 at % Tm-doped NaY(WO4)2disordered crystals is demonstrated. The maximum output power obtained without cooling the sample was 406 mW at a slope efficiency of 39%.

Tunable laser operation of Yb:NaY(MoO 4 ) 2

CW laser operation of Tm³⁺ in Czochralski-grown disordered NaY(WO₄)₂ crystals is demonstrated. The tunability extends from 1847 to 2069 nm. The maximum slope efficiency and output power amount to ap43% and ap400 mW, respectively.

Yb:NaGd(WO/sub 4/)/sub 2/ tunable solid-state laser operation with Ti:sapphire and diode laser pumping

Room temperature laser operation near 1030 nm of Yb³⁺ in the disordered crystal NaGd(WO₄)₂ with slope efficiencies exceeding 30%, output powers more than 300 mW, and tuning from 1016 to 1049 nm are demonstrated

Recent advances in the development of scheelite-like MT1-xLnx(WO4)2 lasers

Tetragonal NaT(WO4)2, T= trivalent Y, La, Gd and Lu, single crystals doped with Yb3+ or Tm3+ have shown efficient room temperature laser operation at λ≈1.05 μm and λ≈1.95 μm, respectively. The broad bandwidth of the optical transitions of these lanthanides is of particular interest for diode-laser-pumped tunable and mode-locked femtosecond lasers. The present knowledge about these crystals and their applications as solid state lasers is overviewed. Results of new material preparation directions to produce epilayers and nano-, micro-particles of these compounds are described.

NaLa(WO 4 ) 2 and NaY(WO 4 ) 2 Raman Converters for Picosecond Pulses

Quasi-steady state SRS with 1.7 ps pulses is investigated in tetragonal NaY(WO₄)₂ and NaLa(WO₄)₂ crystals in the regimes of collinear and noncollinear SRS-assisted four-wave-mixing. Single-pass conversion efficiency of 31% is reported.

Laser Operation of Tm Near 2-µm in the Disordered Double Tungstate Host NaGd(WO 4 ) 2

Lasing with an output power up to 300 mW is reported for Tm:NaGd(WO4)2, both with Ti-sapphire and diode laser pumping. This disordered crystal grown by the Czochralski method allowed tuning from 1813 to 2025 nm.