V. V. Maltsev

Highly efficient continuous-wave diode-pumped Er, Yb:GdAl3(BO3)4 laser

We report the highly efficient continuous-wave diode-pumped laser operation of Er, Yb:GdAl3(BO3)4 crystal. Absorption and stimulated emission spectra, emission lifetimes, and efficiencies of energy transfer from Yb3+ to Er3+ ions were determined. A maximal output power of 780 mW was obtained at 1531 nm at absorbed pump power of 4 W with slope efficiency of 26%.

Passively Q-switched microchip Er, Yb:YAl3(BO3)4 diode-pumped laser.

We report, for the first time to our knowledge, a diode-pumped cw and passively Q-switched microchip Er, Yb:YAl(3)(BO(3))(4) laser. A maximal output power of 800 mW at 1602 nm in the cw regime was obtained at an absorbed pump power of 7.7 W. By using Co(2+):MgAl(2)O(4) as a saturable absorber, a TEM(00)-mode Q-switched average output power of 315 mW was demonstrated at 1522 nm, with pulse duration of 5 ns and pulse energy of 5.25 μJ at a repetition rate of 60 kHz.

Eye-safe 1.55 μm passively Q-switched Er,Yb:GdAl3(BO3)4 diode-pumped laser.

We report for the first time, to the best of our knowledge, on a diode-pumped passively Q-switched Er,Yb:GdAl3(BO3)4 laser. By using a Co2+:MgAl2O4 crystal as a saturable absorber, Q-switched laser pulses with a duration of 12 ns and a maximum energy of 18.7 μJ at a repetition rate of 32 kHz corresponding to an average output power of 0.6 W were obtained at 1550 nm under continuous-wave pumping. In the burst mode of operation, Q-switched laser pulses with the highest energy up to 44 μJ were realized with a pulse repetition rate of 6.5 kHz.

Dispersion and temperature dependence of the refractive indices of pure and Yb 3+ -doped crystals of YAl 3 (BO 3 ) 4

The dispersion of the refractive indices of nominally pure crystals of yttrium orthoborate and of yttrium orthoborate crystals doped with 7at.%Yb3+ has been measured in the visible region. The introduction of 7at.%Yb3+ produces an appreciable increase (in the third place after the decimal) of the refractive indices of the crystal and increases its anisotropy. The temperature dependences of the principal refractive indices have been measured in the range 293–633K, and the first- and second-order temperature coefficients have been found. The refractive index of the extraordinary ray increases with temperature more rapidly by a factor of 1.5–3 (depending on the wavelength) than the refractive index of the ordinary ray.

Liquid-phase epitaxy of single-crystal erbium-ytterbium codoped YAl3(BO3)4 layers as key components of planar waveguides

YAl3(BO3)4 (YAB) crystals 10 × 10 × 8 mm in dimensions were grown on point seeds from a potassium-trimolybdate-based high-temperature solution. The crystals were used as substrates for liquid-phase epitaxy of (Er,Yb):YAB single-crystal films 50 to 100 μm in thickness. The hexagonal cell parameters of nominally undoped and erbium-ytterbium codoped YAB were determined as functions of temperature by high-temperature X-ray diffraction and were used to evaluate the thermal expansion coefficients of the materials. We have demonstrated waveguiding and measured the optical loss in the films.

Flux growth and laser-related spectroscopic properties of (Er,Yb):LuAl3(BO3)4 crystals

Phase relationships in the Er:YbxLu1−xAl3(BO3)4–K2Mo3O10–B2O3–(Lu,Er,Yb)2O3 (x = 0–0.2, Er = 1 at%) system have been studied in the temperature range from 1150 to 900 °C. Multicomponent Li2WO4–B2O3 and K2Mo3O10–B2O3–Lu2O3 melts were used as reasonable fluxes for the high-temperature solution growth of LuAl3(BO3)4 (LuAB) single crystals. The LuAB solubility in the complex flux composition has been found at 25 wt% with decreasing temperature in the temperature interval of 1130–900 °C. (Er,Yb):LuAB single crystals were grown on dipped “point” seeds. The absorption spectra of (Er,Yb):LuAB crystals were measured at room temperature. The emission spectrum and lifetime of the 4I13/2 energy level were determined.

Vibrational spectroscopy of GdCr3(BO3)4: quantitative separation of crystalline phases

This work is devoted to the investigation of GdCr3(BO3)4 crystals by the method of infrared spectroscopy. Incongruently melting borate GdCr3(BO3)4 was obtained as a result of spontaneous crystallization. Crystal structures were identified by the method of infrared spectroscopy. Ab initio calculations in the frame of density functional theory enabled us to separate modes belonging to the R32 and C2/c phases and to estimate the ratio of these phases in GdCr3(BO3)4 crystals. We have found that the content of the rhombohedral R32 (non- centrosymmetric) modification is about 85%.

Laser Performance of Er,Yb:YAl3(BO3)4 Crystals with Different Erbium Concentrations

The effect of erbium concentration on the laser performance of Er,Yb:YAl3(BO3)4 crystals was investigated. A maximal output power of 1.6 W in CW and 2.7 W in QCW regimes was obtained at 1522 nm.

Er,Yb:YAB laser with high output power

In this work we present spectroscopy, continuous-wave (cw) and Q-switched laser operation of Er,Yb-codoped YAl3(BO3)4 (Er,Yb:YAB) crystal under diode pumping. Single crystal of Er(1 at.%),Yb(11 at.%):YAB with dimensions of 15times15times20 mm was grown by the TSSG method using K2Mo3O10 based fluxes. The concentration of the dopants was measured by microprobe analysis. In conclusion, spectroscopic properties and CW and passively Q-switched diode-pumped laser performance of Er,Yb-codoped YAB crystals have been characterized. The results of laser experiments with more powerful diode pumping and cw output power exceeding 300 mW will be presented at the conference. Laser experiments were performed with a nearly hemispherical cavity consisting of 50-mm radius-of-curvature output coupler and plane high reflector.

Structural minals and generic relationship between complex copper-containing oxides

Abstract The structures of complex Cu-containing oxides are analyzed in the fragment approximation. The difference between intrinsic oxides and cuprates is emphasized. The characteristic structural modules, minals, are distinguished according which cuprates are divided into separate groups. The generic relationship between various cuprates is revealed and discussed.