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A high quality Er 3+ /Yb 3+ :Lu 0.5 Gd 0.5 VO 4 crystal with dimensions of 20 × 24 × 28 mm 3 has been grown successfully by the Czochralski method. The concentrations of Er 3+ and Yb 3+ in the Er 3+ /Yb 3+ : Lu 0.5 Gd 0.5 VO 4 crystal were calculated to be about 0.95 mol% and 1.68 mol%, respectively. The XRD pattern of the crystal confirmed that it is isostructural with pure GdVO 4 and LuVO 4 single crystals. The thermal properties of the crystal were studied by analyzing specific heat, thermal expansion coefficients and thermal diffusivity. The spectroscopic characterizations of the crystal, including the polarized absorption spectra and fluorescence spectra were recorded at room temperature. Spectral parameters such as the intensity parameters ( Ω 2 , Ω 4 and Ω 6 ), oscillator strengths, radiative transition probability and radiative lifetime of Er 3+ were calculated by Judd-Ofelt theory. All the results suggest that Er 3+ /Yb 3+ : Lu 0.5 Gd 0.5 VO 4 crystals can be an excellent candidate laser material.

Large sized Fresnoite Ba 2 TiSi 2 O 8 single crystals were grown by the Czochralski method. Using coordinate transformation methods, the relative dielectric, piezoelectric and elastic constants of Fresnoite Ba 2 TiSi 2 O 8 as a function of orientation were investigated, and their two- and three-dimensional spatial distributions are presented. From them, the maximum values of the piezoelectric coefficients and the corresponding rotation angle can be obtained. The maximum values of coefficients d 22 ∗ , d 23 ∗ , d 24 , ∗ d 32 ∗ , d 33 ∗ and d 34 ∗ were achieved for rotation angles of 40°, 32°, 0°, 58°, 50° and 90°, respectively, and are on the order of 8.7, −4.7, 17.5, 4.7, 8.7 and 17.5 pC/N, respectively. Furthermore, the validity of the electromechanical properties investigation as a function of orientation was verified. The relative dielectric permittivity, elastic constant and piezoelectric coefficient of a ZXl50 o cut rod were calculated and found to be 14.1, 8.7 pC/N and 11.2 pm 2 /N, respectively, in good agreement with the experimental values of 12.7, 9.1 pC/N and 11.7 pm 2 /N. This investigation is important in providing direction for theoretical research and device design of piezoelectric Ba 2 TiSi 2 O 8 crystals.

Copper doped KTN crystals with different doping concentrations were grown by the Czochralski method. The XRD patterns show that all of the crystals are in cubic phase at room temperature. The influences of the CuO doping concentrations on dielectric properties of the crystals were measured. Cu: KTN crystals exhibited color changes depending on the doping concentrations. It was found that the inhomogeneous composition property can be used to form gradient refractivity effect in the case of ion doping. The refractive index gradient reaches 33×10−3/mm for the grown Cu: KTNN crystals. Base on the interaction between the quadratic electro-optic effect and the gradient refractivity effect, the deflection and the intensity of a Cu: KTa0.62Nb0.38O3 sample were modulated in different orientations of the crystal. The deflection efficiency and the half-wave voltage of the modulation are 45 mrad/kV and 75 V, respectively.

A millimeter-sized LiNd(MoO 4 ) 2 crystal has been grown using the flux method. LiNd(MoO 4 ) 2 crystallizes in the scheelite-type structure with space group I4 1 /a, lattice parameters: a =5.26090(10) A, c =11.5395(3) A, V =319.379(15) A 3 , and Z =2. The full-matrix, least-squares refinement with R =1.64 % and R w =4.34 % shows that the Li and Nd atoms are completely disordered at jointly occupied sites. The theoretical growth morphology with indexed ( hkl ) planes was developed from the Bravais–Friedel–Donnay–Harker (BFDH) theory and it is in good agreement with the morphology of the as-grown crystals. The chemical composition was analyzed using an inductively coupled plasma emission spectrometer. The full set of thermal properties, including specific heat, thermal expansion, thermal diffusivity, and thermal conductivity of LiNd(MoO 4 ) 2 are reported. The UV–visible diffuse reflectance spectrum contains many strong and broad Nd 3+ absorption lines over the spectral range from 300 to 1000 nm. Three transition emission bands located at 890, 1064 and 1335 nm are observed in the fluorescence spectrum. The fluorescence lifetime is measured to be 2 μs at room temperature. LiNd(MoO 4 ) 2 possesses a large absorption cross section of 1.04×10 −20 cm 2 at 804 nm and an emission cross section of 4.8×10 −20 cm 2 at 1064 nm.

We succeeded in growing gray-track-resistant KTP single crystals in a KTP–K 6 P 4 O 13 (K 6 )–PbO system using TSSG (top-seeded solution growth) and have explored the mechanism of gray track formation using combined characterization technologies. The optical and laser properties of the crystals were estimated. To obtain a better understanding of the gray track effect, in situ X-ray absorption near-edge structure (XANES) measurements using the total electron yield (TEY) method in the region of gray track formation was performed. Electron paramagnetic resonance (EPR) was used to further confirm the existence of Ti 3+ . The results indicate that the formation of the gray track is related to Ti 3+ centers.

A 0.25 at% Nd doped La 0.05 Lu 0.95 VO 4 mixed crystal was grown by the Czochralski method. The thermal properties including thermal expansion, specific heat, thermal diffusion, and thermal conductivity were systematically studied. Meanwhile the reasons for cracking of this mixed crystal were also discussed. The refractive index at wavelengths of 633 nm and 1539 nm were obtained with the prism coupling method. The polarized absorption and fluorescence spectra of the crystal were also measured at room temperature. It was found that the fluorescence lifetime of 4 F 3/2 manifold for Nd 3+ in Nd:La 0.05 Lu 0.95 VO 4 is about 90 μs. Diode-pumped continuous-wave (CW) laser operations at 1.06 μm with a - and c -cut crystals were demonstrated. For the a -cut crystal a maximum output power of 5.41 W was obtained at an incident pump power of 12.9 W. Different from the a -cut crystal, the laser spectrum of the c -cut crystal was found to be dual-wavelength.

A Li3Ba2Nd3(MoO4)8 crystal has been grown by the flux method for the first time. The crystal structure has been refined at room temperature using single crystal X-ray diffraction data. X-ray investigations showed that the newly synthesized compound crystallizes in a monoclinic structure, space group C2/c with the following unit-cell dimensions: a=5.281301 A°, b=12.8725(2) A°, c=19.2549(2) A°, V=1308.83 A°3, Z=2 and ρ=5.095 g cm−3. The absorption and emission spectra of Li3Ba2Nd3(MoO4)8 crystal at room temperature have also been studied. The heat capacity was measured from 25 to 300 °C. These results show that Li3Ba2Nd3(MoO4)8 crystal is a potential laser crystal.

A high-quality Nd 3+ :Sr 3 Y 2 (BO 3 ) 4 laser crystal has been grown by the Czochralski method. The phase purity and accurate unit cell parameters were determined using X-ray powder diffraction; the unit cell parameters are calculated to be a =7.3933 (1) A, b =15.9461 (2) A, c =8.6967 (1) A, and V =1025.29 (5) A 3 . Effective segregation coefficients were measured and the optical homogeneity was further characterized by interferometry. A series of possible growth faces ( hkl ) were also deduced and compared with the as-grown crystal boules using the Bravais–Friedel–Donnay–Harker (BFDH) theory. A full set of thermal properties, including the thermal expansion, thermal diffusivity, specific heat, and thermal conductivity, were measured as a function of temperature. The average linear thermal expansion coefficients along different crystallographic directions were measured to be α 11 =7.04×10 −6 K −1 , α 22 =15.32×10 −6 K −1 and α 33 =14.35×10 −6 K −1 over the temperature range 303.15–770.15 K. The specific heat was measured to be 0.573 J g −1 K −1 (92.64 cal mol −1 K −1 ) at 330 K. The thermal conductivity at room temperature was calculated to be 0.74 W m −1 K −1 , 1.00 W m −1 K −1 , and 0.67 W m −1 K −1 along the a- , b- and c- axis, respectively. It was found that thermal conductivity increases with increasing temperature, which indicates a glass-like behavior.

Hexagonal prism-like and plate-like wurtzite zinc oxide (ZnO) single crystals have been grown in a molten hydrous alkali solution using the spontaneous nucleation method. It has been found that the growth habit of the crystals depends strongly on the basicity of the solution. In molten hydrous KOH solution, the highest growth rate of the crystal is along the + c -axis and slender hexagonal prisms were obtained. In molten hydrous KOH+LiOH or NaOH+LiOH solutions, the growth rate of the + c face slows down as more LiOH is introduced to the solution, resulting in the formation of thin hexagonal plates. This was confirmed by XRD analysis of the single crystals. We conclude that the growth habit of ZnO crystals can be successfully controlled by adjusting the basicity of the solution. It is proposed that there are two individual growth units, [Zn(OH) 3 (H 2 O)] − and [Zn(OH) 4 ] 2− , in the solution. The growth habit can be explained by the polar structure of the ZnO single crystal and the character of the growth units.

Crack-free SrMoO 4 single crystals with high optical quality and large dimensions (O40 x 45 mm 2 ) were successfully grown along a- and c-axis by the Czochralski method. X-ray powder diffraction results show that the as-grown SrMoO 4 crystal belongs to the tetragonal system in the scheelite structure. The result of the rocking curve shows that the symmetry of the diffraction peak is fairly favorable and the full width at half-maximum value was measured to be 94.68". The density of the as-grown crystal was measured to be 4.683 g cm ―3 agreeing well with the theoretical one. Their transmission spectra was measured at room temperature over the wavelength range of 300-3000 nm and the results indicate that the transmittance of SrMoO 4 single crystal is more than 80%, which suggests that the SrMoO 4 crystal has good quality. All the results mean that this crystal should be an excellent Raman material suitable to be used in the operation of stimulated Raman lasers.

The continuous-wave (CW) and passively Q-switched laser performance of a Nd:Gd 0.63 Y 0.37 VO 4 microchip laser are reported. To the best of our knowledge, this is the first time that a mixed vanadate crystal is used as the gain medium in an LD-pumped microchip laser. When the incident pump power was 6.16 W, the CW laser output was 2.09 W, corresponding to an optical conversion efficiency of 33.9% and a slope efficiency of 37.9%. Using a Cr 4+ :YAG crystal as the saturable absorber as well as the output coupler, the pulse width, pulse energy, and peak power were 1.17 ns, 39.5 μJ, and 33.8 kW, respectively.

Trigallium phosphate single crystals, Ga3PO7, have been grown for the first time by a spontaneous nucleation method using Li2CO3-3MoO3 as a flux. The crystal structure was determined by using a four circle X-ray diffractometer. The trigonal unit cell parameters are a = b = 7.897(3) A, c = 6.757(6) A, and Z = 3 with space group R3m. The crystal has a Mohs hardness of 6.5 and a density of 4.874 g/cm3 as determined by using Archimedes’ method. Analysis of differential scanning calorimetry (DSC) and thermogravimetric (TG) shows that the crystal is stable over the temperature range of 25 to 1364.8 °C with no mass change. It has a wide transmission range from 250 to 4300 nm from UV through the IR region. The useful piezoelectric properties have been characterized, and the results show that it is a promising candidate for high temperature piezoelectric applications.

A scandium orthovanadate (ScVO4) single crystal doped with Nd at a concentration of 0.5 at% with dimensions of ϕ8×35 mm2 has to our knowledge for the first time been successfully grown by the floating zone method. The absorption spectrum was measured at room temperature, showing that the transition from 4I9/2 to 4F5/2+2H9/2 is centered at 810 nm with FWHM 6.9 nm. Laser performance of the Nd:ScVO4 crystal at 1068 nm was demonstrated. A maximum average output power of 240 mW was achieved under a pump power of 5.19 W.

Single crystal of Yb:LuAl 3 (BO 3 ) 4 (Yb:LuAB) was grown by the flux method for the first time. The cell parameters of the grown crystal were estimated by X-ray diffraction analysis. The result indicates the symmetry of trigonal space group R32, with lattice parameters a = b =9.26372 A, c =7.21405 A, V =536.14 A 3 , and Z =4. The absorption and emission spectra of Yb:LuAB crystal at room temperature has also been studied. The fluorescence lifetime for Yb:LuAB crystal is about 1.48 ms. The heat capacity was measured from 25 to 500 °C. Its second harmonic generation efficiency in LuAl 3 (BO 3 ) 4 crystal is 3–4 times that of KDP crystal. These results show that Yb:LuAB crystal would be a potential self-frequency-doubling laser crystal.

Ga 3 PO 7 crystal with size 18×15×12 mm 3 and good optical quality has been grown by the top-seeded solution growth (TSSG) slow-cooling method from a Li 2 O–3MoO 3 flux system. The Vickers microhardness and optical properties of the as-grown Ga 3 PO 7 crystal have been carefully studied. The results show that the Ga 3 PO 7 crystal belongs to the harder materials, and Meyer's index numbers for (1 1 0) and (0 0 1) planes were about 1.45 and 1.60, respectively. The Ga 3 PO 7 crystal has a wide transmission range from 215 to 4300 nm. The smaller difference between the refractive indices values of n o and n e indicated that the Ga 3 PO 7 crystal is an optically uniaxial negative crystal.

A new series Nd:Lu x Gd 1− x VO 4 ( x =0.14, 0.32, 0.50, 0.61, 0.70 and 0.80) mixed laser crystals have been successfully grown by the Czochralski method. The X-ray powder diffraction (XRPD) analysis shows that the as-grown mixed crystals possess the ZrSiO 4 structure. The cell parameters are found to decrease with an increase of x . The optical absorption spectra of the mixed crystals have been measured at room temperature, and five strong-absorption bands centered at the wavelengths of 531, 594, 752, 807 and 880 nm have been revealed in all crystals. They are assigned to the different spin- and electric-dipole-allowed transition from the ground state to the 2 K 13/2 + 4 G 7/2 + 4 G 9/2 , 4 G 5/2 + 2 G 7/2 , 4 F 7/2 + 4 S 3/2 , 4 F 5/2 + 2 H 9/2 and 4 F 3/2 energy levels, respectively. A continuous-wave (CW) laser output has been achieved with the mixed crystals at 1.06 μm under laser diode pumping. The maximum CW output power of 377.4 mW has been obtained with the pump power of 2 W, and the corresponding optical conversion efficiency is 18.8%.

Cubic KTa 1− x Nb x O 3 (KTN) single crystals with different compositions have been grown by the Czochralski technique in a KTaO 3 –KNbO 3 solid-solution system. The growth habit, morphological features, and other basic properties of the KTN crystal are discussed. The composition of the crystals was measured by electron probe microanalysis. The Nb composition of the crystals is x (Nb) =0.14, 0.19 and 0.33, corresponding to three different raw materials ratios: Ta 2 O 5 :Nb 2 O 5 (mol)=0.65:0.35, 0.55:0.45 and 0.35:0.65, respectively. The corresponding segregation coefficients are α Nb =0.400, 0.402, and 0.508, respectively. X-ray diffraction results show that the crystals belong to the cubic phase, with lattice parameters a =4.00289, 4.00251 and3.99279 A, corresponding to compositions x (Nb)=0.14, 0.19, 0.33, respectively. The transmittance spectra of the crystals show that they have a broad transparent wavelength range from 385 to 3200 nm, except for an absorption band near 2865 nm. The electro-optical coefficient of the crystals was measured by using a Mach–Zehnder interferometer.

Self-seeded growth of aluminum nitride single crystals in BN crucible was conducted by sublimation method. It was found that the growth temperature played a critical role in the determination of the crystal morphologies and the appearance crystalline planes. The (0 0 0 1) and pseudo ( 1 1 2 ¯ 0 ) planes were often present at low and high temperature, respectively. The self-seeded crystals possess high structural quality which were assessed by high resolution X-ray diffractometry with a full-width at half-maximum of 35.76 arcsec. Step flow mechanism for the growth of AlN similar to SiC growth was confirmed with the aid of atomic force microscopy.

Single crystal of Yb, Tm:KLu(WO4)2 (Yb, Tm:KLuW) with the size of 47×32×15 mm3 has been grown by the top-seeded solution growth (TSSG) method. The absorption spectrum was measured at room temperature. The measured specific heat is lower than that of KGd(WO4)2 (0.502 J/g K) at 100 °C, but it is similar to that of Yb:KLuW (0.365 J/g K) at 90 °C. The measured mean linear coefficients of thermal expansion are αc=16.61×10−6 K−1, αc*=15.04×10−6 K−1, αa=11.91×10−6 K−1, αa*=11.50×10−6 K−1, αb=5.91×10−6 K−1. The thermal conductivity coefficients are 2.71, 2.60, 2.22, 3.32 and 3.14 W/mK at 30 °C along the a, a*, b, c* and c directions, respectively. The results indicate that the crystal has a large anisotropy. The large anisotropy indicated that we should heat or cool the crystal with the temperature changing at a lower speed.

La3Ga5.5Nb0.5O14 (LGN) crystal was grown using the Czochralski method. The as-grown crystal is transparent, free inclusions and has no cracks. Specific heat, thermal expansion, dielectric constants and transmission spectrum of LGN crystal have been measured, and the results show these properties are similar to those of La3Ga5SiO14 (LGS) and La3Ga5.5Ta0.5O14 (LGT) crystal. Therefore, an experiment to research the Q-switch properties of LGN was performed. The electro-optical (EO) coefficients were measured and the results show LGN possesses smaller EO coefficients than does LGS and may not be an ideal material for use as an EO Q-switch.

An improved growth technology (the arc-fusion method) has been successfully employed to grow large magnesium oxide (MgO) single crystals with an average size of 4–6 cm. Three adjustable graphite electrodes with different electric currents ( I A > I B > I C ) are applied, which technology is different from the conventional technology (using a uniform current). In addition, a proper control for the efficient use of different currents reduces the number of bubbles in the growth system, which allows us to obtain optically transparent high-purity MgO single crystals. Our present work shows that control of the temperature-gradient field in the whole process is the key to growing high-purity and large MgO single crystals.

Tungstate crystals including potassium rare earth metal double tungstates KRE(WO 4 ) 2 and barium tungstate BaWO 4 are reliable and efficient Raman active crystals. In this paper, we report on the growth, physical properties and laser performance of these crystals. The pump threshold of Nd: KLu(WO 4 ) 2 pumped by a laser diode (LD) is 24 mW, and up to 188.3 mW of cw output at 1.073 μm is obtained with 746 mW pump power. The optical conversion efficiency is 25.3%, and the slope efficiency of the laser is 26.1%. The cw output for Yb:KLu(WO 4 ) 2 at 1.03 μm is 3.4 W pumped by an LD. Below 0.25 mJ pump energy, we obtained 0.07 mJ Raman laser output in the yellow (the first Stokes line at 559.7 nm) and the orange (the second Stokes line at 590.3 nm) with a 30-mm-long c -axis-oriented BaWO 4 crystal. The conversion efficiency of the Raman laser is about 28%.

KLu(WO4)2 (KLuW) crystals with sizes up to 42×32×12 mm3 have been grown from the K2W2O7 solvent system by the top-seeded solution growth (TSSG) slow-cooling method. The crystal structure of monoclinic KLuW crystals has been refined in space group C2/c at room temperature by using single-crystal X-ray diffraction data and the KLuW morphology was studied from the Hartman–Perdok theory. Crystal shapes vary greatly with the seed orientations, whereas {1 1 0}, {1¯ 1 1}, {0 2 0} and {3 1 0} faces are more developed than the others.

SiC polycrystalline was grown by a spontaneous nucleation sublimation method. The microstructures of SiC polycrystalline were observed by transmission electron microscopy. It was found that SiC polycrystalline has highly preferential orientation with the (0 0 0 1) plane lying on the growth surface and there are only small misorientations among different grains. A great number of stacking faults were observed in the SiC polycrystalline film. These stacking faults were tilted to the film surface with different angles. Based on the extinction rule, the properties of the stacking faults were determined.

Calcium barium niobate Ca0.28Ba0.72Nb2O6 (CBN-28) crystals were grown by the Czochralski method. The effective segregation coefficients of Ca, Ba, Na elements in CBN-28 crystal growth were measured, and the rocking curve from 0 0 2 reflection of CBN-28 wafer was also measured by the high-resolution X-ray diffractometer D5005, and the full-width at half-maximum value was measured to be 70.6″. The measured dependence of dielectric constants on temperature showed the Curie temperature of the CBN-28 crystals is between 246.8 and 260 °C. Typical polarization–electric field (P–E) hysteresis loops were measured at room temperature. Ferroelectric 180° domains were observed by scanning electron microscopy (SEM) on the etched (0 0 1) surface of the CBN-28 crystals. The transmittance of [0 0 1]-oriented CBN-28 crystals was measured and the result shows that optical properties of CBN-28 crystal are almost the same as those of SBN for wavelengths between 2500 and 7500 nm.

The crystal of Dy 3+ -doped YAl 3 (BO 3 ) 4 (Dy:YAB) has been grown by top-seeded solution growth method. The dispersion parameters of the refractive indices are measured and fitted by the least-squares method. Optical absorption and emission intensities of Dy 3+ ions in YAB are investigated. Based on the Judd–Ofelt theory, the spectral parameters: intensity parameters Ω t , radiative transition probabilities A J,J ′ , oscillator strengths f J,J ′ and the radiative lifetime of selected levels, have been obtained. The value of integrated emission cross section was also calculated. The results indicate that Dy:YAB may be considered as laser active materials operating near 2.7, 1.7, and 0.6 μm, respectively.

The YbVO 4 polycrystalline materials were synthesized by liquid-phase method. New Yb stoichiometric YbVO 4 single crystals with excellent quality have been grown by Czochralski technique using a - and c -direction seeds. The X-ray powder diffraction experimental results show that the YbVO 4 polycrystalline material and as-grown YbVO 4 crystal all possess the structure of ZrSiO 4 . The rocking curves from (4 0 0) and (0 0 4) diffraction planes of as-grown YbVO 4 single crystal were measured on the High-Resolution X-ray Diffractometer D5005, and the full-width at half-maximum values were found to be 55.08″ for (4 0 0) face and 40.87″ for (0 0 4) face, respectively. The transmittance spectra of YbVO 4 crystal were measured with a - and c -cut crystal samples at room temperature from 200 to 3000 nm, and there is very strong absorption peak near 970 nm. Some properties of YbVO 4 crystal are compared with those of other crystals.

High optical-quality Nd 3 + -doped KLu(WO 4 ) 2 crystal with sizes up to 55 mm × 27 mm × 15 mm has been successfully grown by top-seeded solution growth method. Continuous wave (CW) laser output up to 188.3 mW of Nd 3 + -doped KLu(WO 4 ) 2 crystals at 1.073 μ m (in the F 3 / 2 4 → I 11 / 2 4 channel) has been achieved with a 1 mm Nd:KLuW crystal under pumping by a 2 W laser-diode (LD) at room temperature. The optical conversion efficiency is 25.3%, which is superior to the former results because 20% optical conversion efficiency was achieved with a 10 mm Nd:KLuW crystal by Kaminskii.

The 0.5 and 1 at% Co 2+ -doped lanthanum magnesium hexaluminates (LaMgAl 11 O 19 , LMA) polycrystalline material was synthesized with high-purity (99.99%) La 2 O 3 , MgO, Al 2 O 3 and analytical purity Co(CH 3 COO) 2 ·4H 2 O by the solid-state reaction technique. The blue Co 2+ :LMA single crystal up to Φ 40×50 mm was successfully grown by the Czochralski method. X-ray powder diffraction (XRPD) results show that the as-grown Co:LMA crystal belongs to the hexagonal system and P6 3 /mmc space group. X-ray fluorescence (XRF) analysis indicates that the effective segregation coefficient of Co 2+ ions in the Co:LMA crystal is k eff ( Co ) = 0.7487 . The high crystalline quality of the as-grown Co:LMA crystals was confirmed by High-resolution X-ray diffraction (HRXRD), which showed the full-width half-maximum (FWHM) of the rocking curves to be less than 20 arcsec on the (0 0 8) and (2 0 0) diffraction planes of the 0.5 at% Co:LMA crystal. The average linear thermal expansion coefficients are α 1 = 9.9720 × 1 0 - 6 / K , α 2 = 11.4451 × 1 0 - 6 / K and α 3 = 16.4328 × 1 0 - 6 / K for the 0.5 at% Co:LMA crystal and α 1 = 9.8753 × 1 0 - 6 / K , α 2 = 10.7768 × 1 0 - 6 / K and α 3 = 15.8901 × 1 0 - 6 / K for the 1 at% Co:LMA crystal in the temperature range from 300.15 to 1133.15 K along the three respective crystallophysical axes. The specific heat of the as-grown Co:LMA crystal increases from 565.36 to 825.12 J K −1 mol −1 when the temperature increases from 323.15 to 1163.15 K. The density of the as-grown Co:LMA crystals is measured by the buoyancy method at 22 °C and the results were 4.236 and 4.243 g cm −3 for 0.5 at% and 1 at% Co:LMA crystal, respectively. The thermal diffusion coefficient of the 0.5 at% Co:LMA crystal was measured in the temperature range of 298.15 to 563.15 K. The calculated thermal conductivity is 4.758 (3.238) W m −1 K −1 along the X 2 ( X 3 ) crystallophysical direction at 328.15 K. These thermal properties show Co:LMA crystal may be used in high-power laser system.

The undoped rubidium gadolinium bis(tungstate) crystals, RbGd(WO 4 ) 2 (RGW), have been grown by the spontaneous nucleation from high-temperature solutions. The crystal structure has been refined at room temperature by using single-crystal X-ray diffraction data. The unit-cell parameters are a =10.6953(12) A, b =10.5017(11) A, c =7.6064(11) A, β =130.504(7)°, with Z = 4 in space group C2/c, which is a little difference with KGd(WO 4 ) 2 . Crystal habits were predicted by the attachment energy model of Hartman and Perdok and we compared predictions to experimentally grown crystal shapes.

Nd-doped gadolinium vanadate (Nd:GdVO4) films have been grown on La3Ga5SiO14 (LGS) and sapphire substrates by pulsed laser deposition for the purpose of fabricating diode-pumped waveguide lasers. Films were grown over a range of temperatures from 600 to 700 °C in the presence of an oxygen pressure between 2 and 20 Pa. Films were characterized by X-ray diffraction, atomic force microscopy, and prism coupling method. Nd:GdVO4 films on different substrates show preferential growth along (2 0 0) with smooth surface. However, films fabricated on sapphire substrates have better crystallization quality compared with that on La3Ga5SiO14 (LGS) substrates according to the X-ray analysis. Films with sharper dips were observed on sapphire substrates in comparison with that on LGS substrates, which means a good confinement of the light in the corresponding mode.

Magnesium oxide (MgO) single crystals with an average size of 6 cm have been grown by an arc-fusion method. X-ray powder diffraction and ultraviolet transmittance spectra are used to characterize properties of the obtained MgO single crystals. In addition, an efficient method for the proper use of three electrodes is applied to reduce the number of bubbles in the obtained MgO sample, which allows us to gain optically transparent high-purity MgO single crystals. Our present work shows that the control of the temperature field of the whole system is crucial to grow high-purity MgO single crystals with large and super-large sizes.

High-quality Nd:LuVO4 single crystal was successfully grown by Czochralski method. The assessment of the crystalline quality by the chemical etching method and Conoscope image was reported. The absorption spectra from 300 to 1000 nm and emission spectra from 960 to 1450 nm of Nd: LuVO4 were measured. Laser performance was achieved with Nd:LUVO4 crystal for the transition of F-4(3/2) -> I-4(11/2) (corresponding wavelength 1065.8 nm) in an actively Q-switched operation, and the average output power reached 5.42 W at a pulse repetition frequency (PRF) of 40 kHz under pump power of 18 W, giving an optical conversion efficiency of 30.1%. The pulse energy and peak power reached 138 mu J and 16.2 kW at PRF of 25 kHz under pump power of 14.2 W, and the pulse duration was 8.5 ns. (c) 2005 Elsevier B.V. All rights reserved.

High-quality Nd-doped gadolinium vanadate thin films on silica glass substrates were fabricated successfully by using a pulsed laser deposition technique. The properties of the samples were characterized by using X-ray diffraction, Rutherford backscattering, atomic force microscopy (AFM), and prism-coupling measurements. The RBS shows no obvious evidence for interdiffusion between the film and the substrate. The ratio of Gd/V in the film is 0.995. X-ray diffraction results show that the as-deposited Nd:GdVO 4 film is basically oriented polycrystalline, and strong (2 0 0) peak was revealed. The refractive indices of the films determined with dark-mode prism coupling measurements are slightly smaller than that of the bulk crystal.

High-quality Nd-doped lutecium vanadate thin films on sapphire substrates have been deposited by pulsed laser deposition (KrF excimer laser). The substrate temperature during the deposition was in the range 600–700 °C under different oxygen pressure between 2 and 20 Pa. The quality of films and crystallographic relationships were assessed by X-ray diffraction, atomic force microscopy (AFM), and prism-coupling measurements. The refractive indices of the films have been inferred from dark-mode prism coupling measurements and are slightly smaller than that of the bulk crystal.

In this paper, barium tungstate single crystal grown by the Czochralski method was reported. The structure of BaWO 4 crystal was characterized by X-ray powder diffraction (XRPD) and the result shows that BaWO 4 crystal belongs to the scheelite structure. Subsequently, its thermal and optical properties were studied by measuring the thermal expansion, specific heat and transparence spectra. These results show that BaWO 4 crystal possesses large anisotropic thermal expansion and its thermal expansion coefficients are α a = 4.8 × 1 0 - 6 / K , α b = 5.1 × 1 0 - 6 / K and α c = 2.3 × 1 0 - 5 / K from 298.15 to 573.15 K, respectively. The reason for large anisotropic thermal expansion coefficients along different crystallographic axes was discussed according to the structure of BaWO 4 crystal. The measured specific heat value is 0.31–0.36 Jg −1 K −1 in the temperature range of 336.15–573.15 K, and the result is in consistent with the value calculated according to Dulong–Petit law of specific heat. The impact of large anisotropic thermal expansion on crystal growth and processing was also discussed. The cutoff wavelength of BaWO 4 crystal is 255 nm and the optical transparency range is 255–3700 nm at room temperature.

Low Nd-doped 0.3 at% Nd:GdVO 4 crystal with excellent crystal quality was grown by the Czochralski method. The maximum CW output power of 8.23 W was obtained when the 0.3 at% Nd:GdVO 4 crystal was pumped by a laser diode with power 27.9 W, giving the corresponding optical conversion efficiency of 29.5% and the average slope efficiency of 30.2%. The fracture-limited pump powers of different Nd-doped crystals were estimated.

Nonlinear optical crystal BiB 3 O 6 grown by using seed crystals with different orientations resulted in different morphologies, dimensions and qualities. In order to find out the optimal seed orientation, thermal expansion property of BIBO crystal was investigated. By analyzing the thermal expansion ellipsoid, the optimal seed orientation seems to be [ 1 ¯ 0 1 ] . High-quality BIBO crystals with dimensions up to 30×30×40 mm 3 and weight of 120 g have been grown using [ 1 ¯ 0 1 ] seed under an appropriate growth conditions.

ZnO films with preferred orientation along the (0 0 2) plane were fabricated by the sol–gel method using a spin-coating technique. The effects of annealing process on the microstructure, transparent properties, and morphology of ZnO films were studied. The films which were dried at 300 °C and then postheated at 600 °C showed the preferred (0 0 2) orientation of ZnO and high transmittance above 80% in the visible range. Also, SEM images of the films showed microstructure consisting of many round shaped particles for the films heated at 400 °C and 500 °C and hexagonal particles as the temperature increased to 600 °C.

Yttrium aluminum garnet (YAG) powder was synthesized by a mixed solvothermal method under moderate conditions ( 260 – 290 ∘ C , 2–4 h) with inexpensive aluminum and yttrium hydroxides as the precursors, and a low-cost ethanol–water solution (the volume ratio of ethanol to water ⩾ 2 : 1 ) as the solvent. The presence of ethanol in mixed solvent is beneficial to the formation of YAG. The synthesized powder consists of well-dispersed and nearly spherical fine grains (80 nm on average) with a relatively narrow grain size distribution. The powder form is the most desirable for the compacting and sintering of YAG ceramics.

Bi 2 Se 3 nanobelts with a typical width of 20–80 nm, thickness of 8–10 nm and length of several micrometers have been successfully synthesized. Synthesis was carried out using a simple co-reduction method under ultrasonic irradiation for 15 h at room temperature. The product was characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), electron diffraction (ED), and high-resolution transmission electron microscopy (HRTEM). The results indicate that the Bi 2 Se 3 nanobelts are well-crystallized nanocrystals and grow along the (0 0 1) direction. The morphology and size of the nanostructures vary with synthesis temperature. A possible formation mechanism of Bi 2 Se 3 nanobelts is proposed.

In this paper, polycrystalline materials of BaWO 4 were synthesized by solid-state phase method, and a single crystal of BaWO 4 was successfully grown along a and c -axis direction by using the Czochralski method. Up to 20×22×80 mm 3 BaWO 4 crystal was obtained, and X-ray powder diffraction results show that the as-grown BaWO 4 crystal belongs to the scheelite structure. The effective segregation coefficients of Ba and W of the BaWO 4 crystal were measured by the X-ray fluorescence method, and the effective segregation coefficients of Ba and W were near 1. The rocking curve from (2 0 0) diffraction plane of as-grown BaWO 4 single crystal was measured on the High-resolution X-ray diffractometer D5005, and the full-width at half-maximum value was found to be 26.64′′ The density and hardness of the BaWO 4 crystal was measured, the measured density was in agreement with the calculated result, and the Mohs hardness was about 4.

Cesium doped KTP crystals with high optical quality have been grown using a flux growth method in various cesium content starting materials. The transmission curve showed a high transmission near UV absorption edge. The conductivity in z direction of these crystals is one order lower in magnitude than that of KTP. The phase-matching (PM) curves for SHG, SFG of Ce:KTP were determined. An effective blue coherent laser was obtained through SFG process using Ce:KTP crystal.

Sm:YAl 3 (BO 3 ) 4 crystal of good optical quality has been grown by the fluxed method. X-ray diffraction experiment show that the crystal has the same structure as that of YAl 3 (BO 3 ) 4 crystal and its unit cell constants have been measured to be a =9.28954 A, c =7.24132 A, vol=541.17 A 3 . The thermal properties of Sm:YAl 3 (BO 3 ) 4 crystal have been studied for the first time. The average thermal expansion coefficients are determined to be 2×10 −6 /°C, 9.5×10 −6 /°C along a - and c -direction. The specific heat of the crystal has been measured to be 0.71 J/g °C at room temperature.

Single crystal of holmium, ytterbium-codoped yttrium aluminum tetraborate Ho,Yb:YAl3(BO3)4(Ho,Yb:YAB) has been grown by the flux method. The crystal structure still belongs to the space group R32. The absorption spectra in the visible and NIR regions have been measured at room temperature; and fluorescence spectrum of Ho,Yb:YAl3(BO3)4 crystal are also measured at room temperature excited by 976 nm laser. Not only the strong NIR emission peaks located at 1966 nm was observed, but also the visible upconversion luminescence has been found. The most strong upconversion luminescence of the Ho,Yb:YAl3(BO3)4 crystal is 5S5→5I8 transition (570 nm), and that of 5F5→5I8 transition (652 nm) of Ho3+ ion is 1.3 times smaller relatively. The mechanism of upconversion luminescence was discussed.

In this paper, the polycrystalline materials of LuVO 4 and NdVO 4 have been synthesized by liquid-phase method, and the new laser crystal Nd:LuVO 4 has been successfully grown by the Czochralski method. The X-ray experimental results show that the polycrystalline materials of LuVO 4 and NdVO 4 , and the as-grown Nd:LuVO 4 crystal all possess the structure of ZrSiO 4 . The laser output of Nd:LuVO 4 crystal is performed when it is pumped by a laser diode.

Sr 3 TaGa 3 Si 2 O 14 (STGS) crystal boules were grown by the Czochralski method using Z -, Y - and X -axis seed, respectively. Crystal growth experimental results show that a perfect crystal could be grown by using the X -axis seed, and the as-grown crystal boule is transparent with free inclusion and no crack. The X-ray powder diffraction (XRPD) analysis shows that the structure of STGS crystal is the same as that of La 3 Ga 5 SiO 14 (LGS) crystal. The XRPD pattern was calculated and indexed by using the program TREOR. The segregation coefficients of Sr 3+ , Ta 5+ , Ga 3+ and Si 4+ ions in crystal growth were measured by using the X-ray fluorescent analysis method, and the results show that the chemical compositions of the as-grown STGS crystals are consistent with their raw materials. The special heat, the thermal expansion and the transmission spectrum of STGS have been measured too, and the results show STGS possesses better thermal properties and transmittance than LGS. The test result on the Q-switch properties indicates STGS has poor electrooptic effect and may not be used as a Q-switch.

La 3 Ga 5 SiO 14 (langasite, LGS) was successfully grown by the Czochralski method. The transparency range, specific heat, thermal expansion, resistivity, dielectric constants, optical damage threshold and electrooptic (EO) coefficients of langasite crystal, have been determined. The transmission spectrum showed that the UV absorption edge of the colorless crystal is about 240 nm. The EO coefficients γ 11 and γ 41 are measured by the interferometric method and are 2.3 and 1.8 pm/V, respectively. A new EO Q-switch was successfully designed and fabricated by using the LGS crystal. The experimental results show that the new EO Q-switch made of langasite works properly. This is the first time that an EO Q-switch has been successfully operated with LGS as an EO crystal.

Single crystal of dysprosium-doped yttrium aluminum tetraborate Dy:YAl 3 (BO 3 ) 4 (Dy:YAB) has been grown by the flux method. The crystal structure is still belongs to the space group R 32 . The absorption spectrum and fluorescence spectrum of Dy 3+ :YAl 3 (BO 3 ) 4 crystal are measured at room temperature. There are four emission transitions occurred at 482, 572, 660 and 754 nm, but the yellow emission transitions ( 4 F 9/2 → 6 H 13/2 ) at 572 nm is more intense than other transitions.