Growth, Thermal and Polarized Spectral Properties of Nd3+-Doped Gd1-xLaxCa4O(BO3)3 (x ) 0.16 and 0.33) Crystals Bo Wei,†,‡ Zhoubin Lin,† Lizhen Zhang,† and Guofu Wang*,† Fujian Institute of Research on the Structure of Matter, State Key Laboratory of Structural Chemistry, Chinese Academy of Sciences, Fuzhou, Fujian 350002, China, and Department of Chemistry and Material Engineering, Changshu Institute of Technology, Changshu, Jiangsu 215500, China
CRYSTAL GROWTH & DESIGN 2008 VOL. 8, NO. 1 186–191
ReceiVed September 5, 2006; ReVised Manuscript ReceiVed October 8, 2007
ABSTRACT: Nd3+:Gd1-xLaxCa4O(BO3)3 crystals (where x ) 0.16 and 0.33) have been grown successfully by the Czochralski method. The grown Nd3+:Gd1-xLaxCa4O(BO3)3 crystals were characterized by X-ray diffraction, thermal analysis, and spectral analysis. The investigation shows that when the La3+ were partly substituted for the Gd3+ in Nd3+:GdCOB crystals to form Nd3+: Gd1-xLaxCa4O(BO3)3 crystals, the La3+ ion did not affect the basic physical properties of the crystals, but improved the thermal and spectroscopic properties of the crystals, which is helpful to improve the laser performance of Nd3+:GdCOB crystals. Introduction During the last 10 years, calcium gadolinium oxoborate [GdCa4O(BO3)3, GdCOB] crystals, which is a member of the ReCa4O(BO3)3 family (where Re ) Y, La, Gd) with space group Cm,1–3 has been widely investigated. The GdCOB crystal is an efficient nonlinear optical material with a large transparent range, high damage threshold, and nonhygroscopic properties. 4–8 In addition, since Gd in GdCOB crystals can be replaced by the active ion Nd3+ or Yb3+, Nd3+- or Yb3+-doped GdCOB crystals were regarded as potential self-frequency doubling laser crystals. 9–20 When the Gd ion in GdCOB crystals was partially substituted by other rare-earth ions, such as Y3+, Lu3+, and Sc3+ ions, some of its physical properties were improved. 21–24 For example, by changing the compositional concentration x in Gd1-xLuxCa4O(BO3)3 crystals, the optical birefringence can be controlled, and the noncritical phase matching (NCPA) wavelength for second-harmonic generation (SHG) could be tuned to the range from 792 to 824 nm along the Y-axis and 922–963 nm along the Z-axis.24 Then, if the La3+ ions, which have the largest radii among the rare-earth ions, are partly substituted for the Gd3+ ions in GdCOB to form the solid solution state Gd1-xLaxCa4O(BO3)3 based on the GdCOB crystal, it may have a great influence on the properties of the crystal. Therefore, this paper reports the growth, thermal, and spectroscopic properties of Nd3+:Gd1-xLaxCa4O(BO3)3 crystals (where x ) 0.16 or 0.33). Experimental Section Crystal Growth. Since GdCOB crystals melt congruently, Nd3+: Gd1-xLaxCa4O(BO3)3 (Nd3+:GdLCOB) can be grown by the Czochralski method.25 The chemicals used were CaCO3, H3BO3, Gd2O3, La2O3, and Nd2O3 with 99.99% purity. The raw materials of Nd3+:GLCOB were synthesized by the solid-state reaction method according to the following chemical reaction equation: yNd2O3 + (1 - x)Gd2O3 + xLa2O3 + 8CaCO3 + 6H3BO3) 2Ndy(Gd1-xLax)1-yCa4(BO3)3 + 8CO2 v + 9H2O v 3+
(1)
3+
where y is Nd -doping concentration, x is La concentration (where x ) 0.16 or 0.33). The excess of 3 wt% H3BO3 was added to compensate for the evaporation of B2O3 during growth. Before the solid* Corresponding author. Tel.: +86-591-83713636; fax: +86-591-83714636; e-mail:
[email protected]. † Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences. ‡ Changshu Institute of Technology.
Figure 1. Grown crystals of (a) Nd3+:GdL0.16COB and (b) Nd3+:GdL0.33 COB. Table 1. Concentration Analysis of the Nd3+:G1-xLxCOB Crystals crystal
La (at %)
Nd (at %)
Nd3+:GdLa0.16Ca4O(BO3)3 Nd3+:GdLa0.33Ca4O(BO3)3
16.00 32.62
2.06 2.50
state reaction, the samples were mixed and extruded to form pieces. Then the samples were placed in the crucible and held at 1200 °C for 24 h to prepare the polycrystalline materials. Nd3+:GdLCOB crystals were grown by the Czochralski method in a 2 kHz frequency furnace heating an iridium crucible in N2 atmosphere. The synthesized raw materials were molt in an iridium crucible with 45 mm diameter and 40 mm height. The melt was held at 1550 °C for 2 h to evacuate the bubbles out of the melt. A seed of GdCOB with [010] orientation was applied to grow Nd3+:GdLCOB crystals. After the seed was repeated and the heating power of the furnace was adjusted, Nd3+:GdLCOB crystals were grown at a pulling rate of 0.5–2 mm/h and a rotating rate of 10–20 rpm. Because the crystal tended to j in the annealing process, a slow cleave along faces (010) and (201) cooling rate of 10-20 K/h was applied in the annealing process to relax the thermal stress in the crystal. As a result, Nd3+:GdLCOB crystals with dimensions φ20 × 25 mm3 and φ15 × 35 mm3 were obtained, respectively, as shown in Figure 1. The samples cut from the top, middle, and bottom of each crystal were used to measure the Nd3+ and La3+ concentrations in both crystals using inductively coupled plasma and atomic emission spectrometry (ICP-AES) techniques. The Nd3+ and La3+ average concentrations in both crystals are listed in Table 1. The compositions of both grown crystals are Nd0.02Gd0.82La0.16Ca4O(BO3)3 (Nd3+:GdL0.16COB) and Nd0.03Gd0.64La0.33Ca4O(BO3)3 (Nd3+:GdL0.33COB), respectively. The hardness of the both crystals was measured using a 401MVA Vickers-microhardometer. The hardness is 771.1 VDH for the Nd3+: GdL0.16COB crystal and 748.0 VDH for the Nd3+:GdL0.33COB crystal,
10.1021/cg0605887 CCC: $40.75 2008 American Chemical Society Published on Web 11/27/2007
Nd3+-Doped Gd1-xLaxCa4O(BO3)3 Crystals
Crystal Growth & Design, Vol. 8, No. 1, 2008 187
Figure 3. The orientation coordinates of the optical indicatrix axes (X, Y, Z) relative to the crystallographic axes (a, b, c) for Nd3+:GdL0.16COB and Nd3+:GdL0.33COB crystals.
Figure 2. XRD patterns of Nd3+:GdL0.33COB crystal. which is about 6.42 and 6.35 on the Mohs’ scale, respectively. The hardness of the both crystals is close to the GdCOB crystal, which is 6.5 on the Mohs’ scale.5,13 X-ray Diffraction (XRD). The lattice parameters of the both crystals were determined by an R3m/E X-ray four-circle diffractometer to be a ) 8.086 Å, b ) 15.988 Å, c ) 3.566 Å and β ) 101.17° for Nd3+: GdL0.16COB and a ) 8.114 Å, b ) 16.001 Å, c ) 3.577 Å and β ) 101.52° for Nd3+:GdL0.33COB. According to the measured lattice parameters, the X-ray diffraction data of the both crystals can be indexed. Figure 2 shows the XRD patterns of the Nd3+:GdL0.33COB crystal. Comparing the lattice parameters of the GdCOB crystal and the XRD data of GdCOB,5,26 it confirms that the grown crystals have been formed in the solid solution state Gd1-xLaxCa4O(BO3)3 based on the GdCOB crystal. The lattice parameters of the both crystals are slightly larger than that of the GdCOB crystal because large La3+ ions (1.032 Å) were partly substituted for the smaller Gd3+ ions (0.938 Å). Crystal orientation is the basis of the crystal physical and optical measurements, which were determined by means of an X-ray diffraction crystal direction finder and a polarized microscopy based on the angular relationship between the crystallographic and optical axes. As Nd3+: Gd1-xLaxCOB is a negative biaxial crystal, there are two sets of axes: the optical indicatrix axes (X, Y, Z) and the intrinsic crystallographic axes (a, b, c). The former axes, which are most commonly used as an orientation reference for laser and nonlinear phase-matching work, are mutually orthogonal and equal to refractive indices (nx, ny, nz). In the monoclinic system, only the b-axis is collinear with the Y-axis. The nonorthogonal a- and c-axis are coplanar but position at certain angles with respect to X- and Z-axis. By means of a YX-2 type X-ray crystal direction finder and a polarized microscopy, and using the standard j and (010), the relationship between the optical axes and faces (201) the crystallographic axes of Nd3+:Gd1-xLaxCOB were determined as b//Y, (a, Z) ) 26.8°, (c, X) ) 15.5° for Nd3+:GdL0.16COB and Nd3+: GdL0.33COB crystals, which is close to that of GdCOB previously reported.5,20 The cross section of a b-axis grown crystal and the axes are shown in Figure 3. Thermal Properties. The specific heat is one of the important thermal factors in laser crystals. Generally, the higher the specific heat is, the larger the laser damage threshold is. The specific heat of the both crystals was measured by a NETZSCH STA 449C Simultaneous Thermal analyzer in a range of 320–550 K. The thermal expansions were measured using a DIL 402PC thermal dilatometer instrument in the range of 350–1050 K along the a-, b-, and c-axes, respectively. Figure 4 shows the dependence of the specific heat of both crystals on the temperature. The specific heat increases almost linearly with the temperature. The specific heats of both crystals at 330 K are listed in Table 2, which are slightly larger than that of GdCOB.17 In comparison with Nd3+:YVO427 (24.6 cal/mol K at 330 K) and Nd3+:GdVO428 (32.6 cal/mol K at 330 K) crystals, Nd3+:Gd1-xLxCOB crystals have a relative
Figure 4. The dependence of the specific heat of Nd3+:Gd1-xLxCOB crystals on the temperature. Table 2. In Comparison of Nd3+:Gd0.16COB and Nd3+:Gd0.33COB with Nd3+:LnCOB Crystal
crystal Nd3+:Gd0.16COB Nd3+:Gd0.33COB Nd3+:GdCOB17,31 Nd3+:YCOB17,32 Nd3+:LaCOB33
Cp(cal/ mol K) at 330 K
Ra (K-1)
94.9 94.7 14.8 × 10-6 80.9 10.2 × 10-6 82.4 9.9 × 10-6 73.7 (300 K)
Rb (K-1)
Rc (K-1)
13.7 × 10-6 8.3 × 10-6 8.2 × 10-6 7.21 × 10-6
17.6 × 10-6 14.3 × 10-6 12.8 × 10-6 10.98 × 10-6
large specific heat. This indicates that Nd3+:Gd1-xLxCOB crystals have a high laser damage threshold. The thermal expansion coefficient is another important thermal factor for crystal growth and applications.29,30 Since Nd3+:Gd1-xLxCOB crystals belong to the monoclinic system, the thermal expansion coefficients of Nd3+:Gd1-xLxCOB crystals are anisotropic. The thermal expansion curves of Nd3+:GdL0.33COB crystal are shown in Figure 5. The average thermal expansion coefficients were calculated from the slopes of the expansion curves, which are listed in Table 2. Spectroscopic Properties. The samples were cut from both as-grown crystals along the x-, y-, and z-axes, respectively, and applied to the spectral measurements. The polarized absorption spectra in the range of 200-1000 nm were measured on a Perkin-Elmer UV–vis-NIR spectrometer (Lambda-900) at room temperature. The polarized fluorescence spectra and fluorescence lifetime were recorded in a range of 850-1400 nm at room temperature using an Edinburgh Analytical Instruments FLS92 spectrometer with excited 810 nm radiation. The polarized absorption spectra of Nd3+:GdL0.16COB and Nd3+: GdL0.33COB crystals are shown in Figures 6 and 7, respectively. The absorption spectra show strong polarized dependence. The interesting
188 Crystal Growth & Design, Vol. 8, No. 1, 2008
Wei et al.
Figure 5. Thermal expansions of the Nd3+:GdL0.33COB crystal along the a-, b-, and c-axes.
Figure 7. Polarized absorption spectra of Nd3+:GdL0.33COB crystal at room temperature. Table 3. Absorption Cross Sections and the fwhm (E//Z) of Nd3+:Gd1-xLxCOB and Comparison with those of 4.0 at% Nd3+:GdCOB and 4.7 atom % Nd3+:YCOB at 812 nm σY σZ FWHM σX (10-20 cm2) (10-20 cm2) (10-20 cm2) (E//Z) (nm)
crystal Nd3+:Gd0.16COB Nd3+:Gd0.33COB 4.0 at% Nd3+: GdCOB13 4.7 at% Nd3+: YCOB34
Figure 6. Polarized absorption spectra of Nd3+:GdL0.16COB crystal at room temperature. features of these spectra, relative to the potential application in the diode pumped lasers, are the strong absorption bands at 812 nm wavelengths that closes to the laser output of AlGaAs diode laser. The absorption cross section σa was determined using σa ) R/Nc
(2)
where R is the absorption coefficient, and Nc is concentration of Nd3+ ions in crystals. Thus, the absorption cross sections are 9.11 × 1019 cm-3 for Nd3+:GdL0.16COB and 1.10 × 1020 cm-3 for Nd3+: GdL0.33COB at 812 nm, respectively. These results are listed in Table 3. On the basis of the Judd-Ofelt35,36 theory, which has become a standard tool for calculating the parity-forbidden electric-dipole radiative transition rates among the various levels of rare earth ions in both glass and crystalline hosts, the absorption spectra data can be used to predict the radiative lifetime of 4F3/2 excited J manifold and transition probability to the lower-lying 4Ij manifold. The calculating procedure involves first the experimental oscillator strength Smea of the transition between the ground state 4I9/2 and the excited J manifold. The experimental oscillator strength Smea can be calculated using the following formula37 Smea q (J f J′) )
3ch(2J + 1) 8π3e2λabsNc
∫R (n + 2) 9nq
2 q
2
abs q (λ)
dλ
(3)
1.78 1.76 1.86
1.59 1.63 1.57
1.86 1.85 2.23
1.5
1.2
2
19 17
where c is the velocity of light, h is Planck’s constant, e is the electron charge, λabs is the mean wavelength of the absorption band, Rqabs is the absorption coefficient at wavelength λ, the subscript q indicates the electric field polarization along the optical indicatrix (X, Y, or Z) of the crystal, and n is the refractive index. For each crystal, the refractive indices along X, Y, Z polarization at 589.6 nm were measured using a refractometer with an Na lamp (λ ) 589.6 nm). The results are very close to those obtained from the Sellmeier equation established for GdCOB,5 and the error is less than 0.005. Therefore, in the subsequent calculation, the refractive indices of different wavelengths are computed from the Sellmeier equation of GdCOB5 0.02347 - 0.00356λ2 λ2 - 0.01300 0.02402 nY2 ) 2.8957 + 2 - 0.01039λ2 λ - 0.01395 0.02471 nZ2 ) 2.9222 + 2 (4) - 0.00820λ2 λ - 0.01279 According to the Judd-Ofelt theory, the line strength of an electricdipole transition between the initial state |〈(S,L)J〉 and terminal state |〈(S′, L′)J′〉 is expressed as follows nX2 ) 2.8065 +
Scal q (J f J′) )
∑ Ω |〈(S, L)J|U
(t)
tq
|(S′, L′)J′〉|2
(5)
t)2,4,6
where U(t) (t ) 2, 4, 6) are the doubly reduced unit tensor operators, which were calculated by Carnall38 for Nd3+, since the reduced matrix elements exhibit only small variations with host lattice.39 By a least-
Nd3+-Doped Gd1-xLaxCa4O(BO3)3 Crystals
Crystal Growth & Design, Vol. 8, No. 1, 2008 189
Table 4. Judd-Oflet Intensity Parameters of Nd3+:Gd1-xLxCOB and Comparison with Other Nd3+:LnCOB Crystal Ω (10-20 cm2)
crystal Nd3+:Gd0.16COB Nd3+:Gd0.33COB Nd3+:YCOB34 Nd3+:GdCOB13 Nd3+:LaCOB23 a
E//X
Ω2 Ω4 Ω6 Ω2 Ω4 Ω6 Ωeffa Ωeff Ωeff
E//Y
E//Z
effective
3.67 2.01 0.18 1.47 2 4.96 1.55 1.17 1.98 3.13 0.21 0.22 1.55 1.2 4.69 1.58 1.31 1.59 Ω2 ) 0.27, Ω4 ) 0.91, Ω6 Ω2 ) 0.36, Ω4 ) 0.88, Ω6 Ω2 ) 1.98, Ω4 ) 2.39, Ω6
1.95 2.81 1.56 1.19 2.48 1.49 ) 0.68 ) 0.51 ) 1.38
Ωeff ) (Ωx + Ωy + Ωz)/3.
Table 5. Polarized Spontaneous Emission Probabilities and Fluorescence Branching Ratios for the 4F3/2f 4I′J Transitions of Nd3+:Gd1-xLxCOB Crystals E//X crystal Nd3+: Gd0.16COB
transition 4
E//Y
A A (s-1) β (%) (s-1) β (%)
E//Z A (s-1)
β (%)
F3/2f 4I9/2 492.4 42.68 641.1 51.16 1550.3 56.14
4
F3/2f4I11/2 552.3 47.87 525.9 41.96 1062.5 38.47 F3/2f4I13/2 103.9 9.01 82.2 6.56 141.8 5.14 4 5.1 0.44 4 0.32 7 0.25 F3/2f4I15/2 4 F3/2f 4I9/2 515.6 43.09 425.8 42.24 1447.4 58.11 4
Nd3+: Gd0.33COB
4
F3/2f4I11/2 569.4 47.58 485.8 48.19 4 F3/2f4I13/2 106.4 8.89 91.9 9.12 4 5.2 0.44 4.5 0.45 F3/2f4I15/2
923.9 37.09 113.8 4.57 5.6 0.22
Figure 8. Polarized emission spectra of Nd3+:GdL0.16COB crystal at room temperature.
root-means-square fitting between eqs 4 and 5, the three intensity parameters Ω2,4,6 for each optical indicatrix were obtained and are listed in Table 4. The spontaneous emission probability of the electric-dipole transition from the initial manifold 4F3/2 (J ) 3/2) to a lower J′-manifold 4I′J can be calculated by the following expression: Aq(J f J′) )
64π4e2 3 3h(2J + 1)λem
nq(n2q + 2)2 Ωtq|〈4F3⁄2 | Ut | 4IJ′〉|2 × 9 t)2,4,6
∑
(6) where λem is the mean wavelength of emission band and the deduced emission transition matrix elements 〈|U(t)|〉 are given by W. F. Crupke.40 Then, the fluorescence branching ratio of each of the transitions is given as βq )
Aq(J f J′)
(7)
∑ A (J f J′) q
J′
The calculated values of Aq and βq with three polarized directions of the two crystals are tabulated in Table 5. The radiative lifetime can be obtained by the reciprocal of the total spontaneous emission probabilities: Figure 9. Polarized emission spectra of Nd3+:GdL0.33COB crystal at room temperature.
∑ ∑ A (J f J′) q
τr-1 ) Atotal )
q
J′
(8)
3 4
3+
3+
Therefore, the radiative lifetimes of the F3/2 for the Nd in Nd : GdL0.16COB and Nd3+:GdL0.33COB crystals are estimated to be 580 and 639 µs for Nd3+:GdL0.16COB and Nd3+:GdL0.33COB crystals, respectively. The fluorescence lifetimes were measured to be 93.9 and 93.2 µs, respectively. The fluorescence quantum efficiencies can be obtained using the following formula: η)
τf × 100% τr
(9)
Thus, the fluorescence quantum efficiencies were calculated to be 16.2 and 14.6% for Nd3+:GdL0.16COB and Nd3+:GdL0.33COB crystals, respectively. The results are similar to the 15% of Nd3+: GdCOB.13 The room temperature polarized fluorescence spectra of Nd3+: GdL0.16COB and Nd3+:GdL0.33COB crystals are shown in Figures 8 and 9, respectively. Three emission bands correspond to the 4F3/2 f 4I9/2, 4F3/2 f 4I11/2 and 4F3/2 f 4I13/2 transitions of Nd3+ ions. The most interesting is the strong sharp emission band corresponding to the 4F3/2 f 4I9/2 transition at 890 nm. The emission intensity of 4 F3/2 f 4I9/2 transition is stronger than that of 4F3/2 f 4I11/2 transition at 1.06 µm for E//Y and E//Z. Therefore, both crystals may be
190 Crystal Growth & Design, Vol. 8, No. 1, 2008
Wei et al.
Table 6. Stimulated Emission Cross Sections at Peak Fluorescence Wavelength for Nd3+:Gd1-xLxCOB Crystals and Comparison with Nd3+:YCOB and Nd3+:GdCOB at 1060 nma E//X
E//Y
E//Z
crystal
λem
σem
λem
σem
λem
σem
Nd3+:Gd0.16COB
890.3 1063.5 1334.4 890.7 1064.0 1334.9 1060 1060
1.40 7.22 2.71 2.78 7.02 2.41 2 1.15
890.3 1063.5 1334.9 890.7 1064.0 1334.9 1060 1060
3.99 7.13 2.09 2.12 5.82 2.03 2.1 1.7
890.3 1063.5 1334.9 890.3 1063.5 1335.3 1060 1060
8.48 13.36 3.56 7.92 10.94 2.49 4.21 2.1
Nd3+:Gd0.33COB Nd3+:GdCOB13,42 Nd3+:YCOB34 a
λem: nm, σem: 10-20 cm2.
possible to achieve laser action at about 890nm. Considering Gd1-xLxCOB crystal is a nonlinear crystal, the blue light at 445 nm can be generated by the frequency conversion. Using the obtained spontaneous emission probability Aq, the stimulated emission cross sections for different polarized directions could be estimated from the room temperature polarized fluorescence spectra by the following formula41 σem q )
Aqλe2 4π2n2q∆νq
(10)
where λe is the emission wavelength, and ∆νq is the frequency full width at half-maximum. The values for different polarized directions are listed in Table 6. It is obvious that the stimulated emission cross sections of the both crystals have no evident difference, but in comparison with the stimulated emission cross section Nd3+:GdCOB at 1060 nm,13,42 both are much larger than the stimulated emission cross section of Nd3+:GdCOB.
Results and Discussion Nd3+:Gd1-xLaxCa4O(BO3)3 crystals (where x ) 0.16 and 0.33) with dimensions φ20 × 25 mm3 and φ15 × 35 mm3 have been successfully grown by the Czochralski method. The crystal orientation was determined by means of XRD crystal direction finder and polarized microscopy based on the angular relationship between the crystallographic and optical axes. The hardness of the both crystals is close to GdCOB crystal, and this result shows that when La3+ ions are substituted for some Gd3+ ions in the GdCOB crystal, it does not affect the basic physical properties of GdCOB crystal. The investigation of the thermal properties shows that the specific heat of both crystals are slightly larger than that of GdCOB, which signifies that both crystals have a high laser damage threshold. On the basis of the Judd-Ofelt theory, the spectroscopic parameters of both crystals were calculated. Comparison with spectroscopic parametersandemissioncrosssectionsofNd3+:GdCOBcrystal,13,20,42 both crystals are larger than that of Nd3+:GdCOB crystal, which is helpful to improve the laser performance. Conclusion When the La3+ were partly substituted for the Gd3+ in Nd3+: GdCOB crystal to form Nd3+:GdL0.16COB and Nd3+: GdL0.33COB crystals, the La3+ ion did not affect the basic physical property of the crystals but improved the thermal and spectroscopic properties of the crystal, which is helpful to improve the laser performance of Nd3+:GdCOB crystals. Acknowledgment. This work is supported by the National Natural Science Foundation of China (No. 60578009) and Key
Project of Science and Technology of Fujian Province (2001F004), respectively.
References (1) Khamaganova, T. N.; Trupov, V. K.; Dzhurinskii, B. F. Russ. J. Inorg. Chem. 1991, 36, 855. (2) Norrestam, R.; Nygren, M.; Bovin, J. O. Chem. Mater. 1992, 4, 737. (3) Ilyukhin, A. B.; Dzhurinskii, B. F. Russ. J. Inorg. Chem. 1993, 38, 917. (4) Aka, G.; Kahn-Harari, A.; Vivien, D.; Benitez, J. M.; Salin, F.; Godard, J. Eur. J. Solid State Inorg. Chem. 1996, 33, 727. (5) Aka, G.; Kahn-Harari, A.; Vivien, D.; Mougel, F.; Salin, F.; Coquelin, P.; Colin, P.; Pelenc, D.; Damelet, J. P. J. Opt. Soc. Am. B 1997, 14, 2238. (6) Iwai, M.; Kobayashi, T.; Furuya, H.; Mori, Y.; Sasaki, T. Jpn. J. Appl. Phys. 1997, 36, 276. (7) Aka, G.; Mougel, F.; Auge, F.; Kahn-Harari, A.; Vivien, D.; Benitez, J. M.; Salin, F.; Pelenc, D.; Balembois, F.; Georges, P.; Brun, A.; Le Nain, N.; jacquet, M. J. Alloys Compd. 2000, 401, 303. (8) Vivien, D.; Aka, G.; Kahn-Harari, A.; Aron, A.; Mougel, F.; Benitez, J. M.; Ferrand, B.; Klein, R.; Kugel, G.; Le Nain, N.; Jacquet, M. J. Cryst. Growth 2002, 237, 621. (9) Vivien, D.; Mougel, F.; Auge, F.; Aka, G.; Kahn-Harari, A.; Valembois, F.; Lucas-Leclin, G.; Georages, P.; Brun, A.; Aschehoug, P.; Benitez, J. M.; Le Nain, N.; Jacquet, M. Opt. Mater. 2001, 16, 213. (10) Druon, F.; Auge, F.; Balembois, F.; Georges, P.; Brun, A. J. Opt. Soc. Am. B 2000, 17, 18. (11) Xia, H. R.; Zheng, W. Q.; Zhang, S. J.; Cheng, Z. X.; Cheng, X. F.; Yang, Z. H. J. Appl. Phys. 2002, 92, 5060. (12) Mougle, F.; Dardenne, K.; Aka, G.; Kahn-Harari, A.; Vivien, D. J. Opt. Soc. Am. B 1999, 16, 164. (13) Mougel, F.; Aka, G.; Kahn-Harari, A.; Hubert, H.; Benitez, J. M.; Vivien, D. Opt. Mater. 1997, 8, 161. (14) Mougel, F.; Auge, E.; Aka, G.; Kahn-Harari, A.; Vivien, D.; Balembois, F.; Georges, P.; Brun, A. Appl. Phys. B: Laser Opt. 1998, 67, 533. (15) Vivien, D.; Mougel, F.; Aka, G.; Kahn-Harari, A.; Pelenc, D. Laser Phys. 1998, 8, 759. (16) Lupei, A.; Antic-Fidancev, E.; Aka, G.; Vivien, D.; Aschehoug, P.; Goldner; Pelle, F. Phys. ReV. B 2002, 65, 224518. (17) Wang, C. Q.; Zhang, H. J.; Meng, X. L.; Zhu, L.; Chow, Y. T.; Liu, X. S.; Cheng, R. P.; Yang, Z. H.; Zhang, S. J.; Sun, L. K. J. Cryst. Growth 2000, 220, 114. (18) Jiang, H. D.; Wang, J. Y.; Zhang, H. J.; Hu, X. B.; Teng, B.; Zhang, C. Q.; Wang, P. Chem. Phys. Lett. 2002, 357, 15. (19) Zhang, H. J.; Meng, X. L.; Wang, P.; Li, Z.; Liu, X. S.; Yang, Y. Y.; Wang, R. H.; Dawes, J.; Piper, J.; Zhang, S. J.; Sun, L. K. J. Cryst. Growth 2001, 222, 209. (20) Zhang, S. J.; Cheng, Z. X.; Han, J. R.; Zhou, G. Y.; Shao, Z. S.; Wang, C. Q.; Chow, Y. T.; Chen, H. C. J. Cryst. Growth 1999, 206, 197. (21) Zhang, H. J.; Meng, X. L.; Wang, C. Q.; Zhu, L; Liu, X. S.; Dong, C. M.; Cheng, R. P.; Liu, X. M.; Wang, R. H.; Zhang, S. J.; Chow, Y. T.; Sun, L. K. J. Cryst. Growth 2000, 210, 815. (22) Zhang, Y.; Hu, Z. S.; Lin, Z. B.; Wang, G. F. J. Cryst. Growth 2005, 390, 194. (23) Zhang, Y.; Lin, Z. B.; Hu, Z. S.; Wang, G. F. Mater. Res. InnoVations 2005, 9, 401. (24) Gheorghe, L.; Loiseau, P.; Aka, G.; Taira, T.; Lupei, V. Proc. SPIEInt. Soc. Opt. Eng. 2006, 6190, 61900Z. (25) Crystal Growth; Pamplin, B. R., Ed.; Pergamon Press: Elmsford, NY,1979, p 497. (26) Mougel, F.; Kahn-Harari, A.; Aka, G.; Pelenc, D. J. Mater. Chem. 1998, 8, 1619. (27) Zhang, H. J.; Zhu, L.; Meng, X. L.; Yang, Z. H.; Wang, C. Q.; Yu, W. T.; Chow, Y. T.; Lu, M. K. Cryst. Res. Technol. 1999, 34, 1011. (28) Zhang, H. J.; Meng, X. L.; Zhu, L.; Yang, Z. H. Mater. Res. Bull. 1999, 34, 1589. (29) Dhanaraj, G.; Srinivasan, M. R.; Bhat, H. L.; Jayanna, H. S.; Subramanyam, S. V. J. Appl. Phys. 1992, 72, 3464. (30) Zhang, H. J.; Meng, X. L.; Zhu, L.; Wang, P.; Liu, X. S.; Yang, Z. H.; Dawes, J.; Dakker, P. Phys. Status Solidi A 1999, 175, 705. (31) Mougel, F.; Kahn-Harari, A.; Aka, G.; Pelenc, D. J. Mater. Chem. 1998, 8, 1619. (32) Luo, J.; Fan, S. J.; Xiao, H. Q.; Qian, S. X.; Zhong, Z. W.; Qian, G. X.; Sun, R. Y.; Xu, J. Y. Cryst. Res. Technol. 2001, 36, 1215.
Nd3+-Doped Gd1-xLaxCa4O(BO3)3 Crystals (33) Jiang, H. D.; Li, D. W.; Zhang, K. Q.; Liu, H.; Wang, J. Y. Chem. Phys. Lett. 2003, 372, 788. (34) Hammons, D. A.; Richardson, M.; Chai, B. H. T.; Chin, A. K.; Jollay, R. IEEE J. Quantum Electron. 2000, 36, 991. (35) Judd, B. R. Phys. ReV. 1963, 127, 750. (36) Ofelt, G. S. J. Chem. Phys. 1962, 37, 511. (37) Fowler, W. B.; Dexter, D. L. Phys. ReV. 1962, 128, 2154.
Crystal Growth & Design, Vol. 8, No. 1, 2008 191 (38) (39) (40) (41) (42)
Carnall, W. T.; Fields, P. R.; Rajnak, K. J. Chem. Phys. 1968, 49, 4424. Gashurov, G.; Sovers, O. J. J. Chem. Phys. 1969, 50, 429. Krupke, W. F. IEEE J. Quantum Electron. 1974, 10, 450. Weber, M. J.; Varitimo, T. E. J. Appl. Phys. 1971, 42, 4996. Brenier, A. J. Nonlinear Opt. Phys. Mater. 2003, 12, 349.
CG0605887
