5 at% Tm-doped NaGd(MoO<sub>4</sub>)<sub>2</sub> laser crystal operated in CW conditions provided up to 641 mW of output power at λ ≈ 1910 nm with a slope efficiency of 50.8% and a pump power laser threshold of 166 mW. 10 at% Tm-doped
Li<sub>3</sub>Ba<sub>2</sub>Lu<sub>3</sub>(MoO<sub>4</sub>)<sub>8</sub> laser operated in quasi-CW conditions provided up to 510 mW of output power at λ ≈ 1950 nm with a
slope efficiency of 71.4% and a pump power laser threshold of 125 mW. Both crystals were grown by the Top Seeded
Solution Growth method at about two hundreds degrees below their melting points. The structural disorder of these
crystals confers inhomogenous broadening to the Tm<sup>3+</sup> electronic transitions. Slightly broader laser tuning range and
laser emission bandwidths are observed in the
Li<sub>3</sub>Ba<sub>2</sub>Lu<sub>3</sub>(MoO<sub>4</sub>)<sub>8</sub> crystal despite of the lower expected degree of
crystalline disorder. The crystals are promising for the development of mode locked ultrafast (fs) lasers with emission
close to λ = 2 μm.
Tetragonal NaT(WO<sub>4</sub>)<sub>2</sub>, T= trivalent Y, La, Gd and Lu, single crystals doped with Yb<sup>3+</sup> or Tm<sup>3+</sup> 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.
The characterization of the coefficient of the nonlinear optical Kerr effect, the nonlinear refractive index (<i>n</i><sub>2</sub>), of several femtosecond laser crystals with compositions derived by total or partial replacement of D<sup>2+</sup> in DXO<sub>4,</sub> X = Mo or W, is presented. Tetragonal (space group <i>I</i>4) Na-based double tungstates NaT(WO<sub>4</sub>)<sub>2</sub> (T = Y, La, Gd, Lu and Bi) and double molybdate NaY(MoO<sub>4</sub>)<sub>2</sub>, as well as the monoclinic (space group C2/c) Li<sub>3</sub>Gd<sub>3</sub>Ba<sub>2</sub>(MoO<sub>4</sub>)<sub>8</sub> crystals, have been measured by the <i>z</i>-scan technique. All these crystals present structural local disorder, and among them the tetragonal ones exhibit significant <i>n</i><sub>2</sub> values, which should allow their efficient laser pulsed operation by Kerr-lens mode locking, especially NaBi(WO<sub>4</sub>)<sub>2,</sub> 68x10<sup>-16</sup> cm<sup>2</sup>/W (for σ light), which is about twice than for the others. This feature is attributed to the high polarizability associated to the lone electron pair of Bi<sup>3+</sup>.
We studied diode pumping of the locally disordered Yb-doped NaY(WO<sub>4</sub>)<sub>2</sub> crystal. An <i>a</i>-cut 1.514-mm thick sample
(6.9 at % Yb doping or 4.52×10<sup>20</sup> cm<sup>-3</sup>) was placed under Brewster angle in a z-shaped astigmatically compensated
cavity, without any active cooling. It was oriented for pumping and emission in π-polarization (E//c). Laser experiments
were performed applying a high brightness laser diode as a pump source. The laser diode delivered up to 2.1 W of input
power and the emission wavelength was selected in the broad absorption peak of Yb:NaY(WO<sub>4</sub>)<sub>2</sub> around 961nm.
Continuous-wave operation in the 1-μm range was obtained for output coupler transmission between 1% and 10%. A
maximum output power of ≈180 mW and slope efficiencies up to 30%, related to the absorbed power, were achieved.
For femtosecond mode-locked operation, a semiconductor saturable absorber mirror as well as two SF10 prisms were
included in the cavity. Aligning the cavity for shortest pulses, we obtained stable passive mode-locking with pulse
durations as short as 97 fs directly from the oscillator. Applying external compression, the pulse duration could be
further reduced to 90 fs with a corresponding time-bandwidth-product of 0.321. The average output power amounted to
59 mW at a repetition rate of 90 MHz and the corresponding output spectrum was centered at 1044 nm.
We report a solution processed blue stilbenoid dendrimer based on a 1, 3, 5 - benzene core and endowed with a periphery
of electron donating and solubilizing alkoxy chains. Raman analysis it is revealed as a helpful tool to investigate changes
from the pristine material to the material in the OLED structure, explaining the differences between the dendrimer single
layer thin film photoluminescence (PL) and the electroluminescence (EL) dendrimer active layer emission in the device.
We report a blue EL emission (439 nm) and a very promising effective mobility value of 2.55 × 10<sup>-5</sup> cm<sup>2</sup>/(V•s)
suggesting good transport properties for non doped blue OLEDs that use air stable Al as the cathode.
A first attempt to growth thin films of Nb doped PZT with 96% of Zr by pulsed laser deposition (PLD) has been done on Pt-sputtered Si (100) single crystal substrates. The target [1.5% Nb doped Pb(Zr<SUB>0.965</SUB>Ti<SUB>0.035</SUB>)O<SUB>3</SUB>] has been ablated in oxygen atmosphere with a focused KrF excimer laser beam. By changing the laser repetition rate and the deposition time, the thickness of the films was selected in the 150-400 nm range. The lead deficiency of the film was reduced by using an oxygen pressure of 75 mTorr as well as by holding the substrates at temperatures not higher than 500 degree(s)C. The results of the characterization show that a first (150-180 nm) layer is the main responsible of the lead deficiency, the low resistivity and the lack of ferroelectric response of the films grown.