Nd:YVO4(掺钕钒酸钇)

Nd:YVO4(掺钕钒酸钇)


Nd:YVO4(掺钕钒酸钇)晶体是一种性能优良的激光晶体,适于制造激光二极管泵浦特别是中低功率的激光器。与Nd:YAG相比Nd:YVO4对泵浦光有较高的吸收系数和更大的受激发射截面。激光二极管泵浦的Nd:YVO4晶体与LBO,BBO,KTP等高非线性系数的晶体配合使用,能够达到较好的倍频转换效率,可以制成输出近红外、绿色、蓝色到紫外线等类型的全固态激光器。

基本特性

Crystal Structure: Zircon Tetragonal, space group D4h-I4/amd
Cell Parameter:  a=b=7.1193 Å, c=6.2892 Å
Density: 4.22g/cm3
Atomic Density: 1.26x1020 atoms/cm3 (Nd 1.0%)
Mohs Hardness: 4-5 (Glass-like)
Thermal Expansion Coefficient (300K): aa=4.43x10-6/K
ac=11.37x10-6/K
Thermal Conductivity Coefficient (300K): //C: 0.0523W/cm/K
^C: 0.0510W/cm/×K
Lasing wavelength: 1064nm, 1342nm
Thermal optical coefficient (300K): dno/dT=8.5´10-6/K
dne/dT=2.9´10-6/K
Stimulated emission cross-section: 25´10-19cm2 @1064nm
Fluorescent lifetime: 90ms(1% Nd doping)
Absorption coefficient: 31.4cm-1 @810nm
Intrinsic loss: 0.02cm-1 @1064nm
Gain bandwidth: 0.96nm @1064nm
Polarized laser emission: π polarization; parallel to optic axis(c-axis)
Diode pumped optical to optical efficiency:  >60%
Sellmeier equations no2=3.77834+0.069736/(λ2-0.04724)-0.010813λ2
ne2=4.59905 +0.110534/(λ2-0.04813)-0.012676λ2

Nd:YVO4的激光特性

1. One most attractive character of Nd:YVO4 is, compared with Nd:YAG, its 5 times larger absorption coefficient in a broader absorption bandwidth around the 808 nm peak pump wavelength, which just matches the standard of high power laser diodes currently available. This means a smaller crystal that could be used for the laser, leading to a more compact laser system. For a given output power, this also means a lower power level at which the laser diode operates, thus extending the lifetime of the expensive laser diode. The broader absorption bandwidth of Nd:YVO4 which may reaches 2.4 to 6.3 times that of Nd:YAG. Besides more efficient pumping, it also means a broader range of selection of diode specifications. This will be helpful to laser system makers for wider tolerance for lower cost choice.

2. Nd:YVO4 crystal has larger stimulated emission cross-sections, both at 1064nm and 1342nm. When a-axis cut Nd:YVO4 crystal lasing at 1064m, it is about 4 times higher than that of Nd:YAG, while at 1340nm the stimulated cross-section is 18 times larger, which leads to a CW operation completely outperforming Nd:YAG at 1320nm. These make Nd:YVO4 laser be easy to maintain a strong single line emission at the two wavelengths.

3. Another important character of Nd:YVO4 lasers is, because it is an uniaxial rather than a high symmetry of cubic as Nd:YAG, it only emits a linearly polarized laser, thus avoiding undesired birefringent effects on the frequency conversion. Although the lifetime of Nd:YVO4 is about 2.7 times shorter than that of Nd:YAG, its slope efficiency can be still quite high for a proper design of laser cavity, because of its high pump quantum efficiency.
The major laser properties of Nd:YVO4 vs Nd:YAG are listed in Table below, including stimulated emission cross-sections (σ),Absorption Coefficient (α) Fluorescent lifetime (τ), Absorption Length (La), threshold Power (Pth) and Pump Quantum Efficiency (η).
 

Nd:YVO4 和Nd:YAG的比较

LASER CRYSTAL DOPING σ α τ La PTH ηs
(atm%) (x10-19 CM2) (cm-1) (μs) (mm) (mw) (%)
Nd:YVO4(a-cut) 1 25 31.2 90 0.32 30 52
2 25 72.4 50 0.14 78 48.6
Nd:YVO4(c-cut) 1.1 7 9.2 90   231 45.5
Nd:YAG 0.85 6 7.1 230 1.41 115 38.6

Typical Results

Diode pumped Nd:YVO4 laser output comparing with diode pumped Nd:YAG laser.

 

Crystals Size (mm3) Pump Power Output (at 1064nm)
Nd:YVO4 3x3x1 850mW 350mW
Nd:YVO4 3x3x5 15W 6W
Nd:YAG 3x3x2 850mW 34mW

Diode pumped Nd:YVO4+KTP green laser.
8W green laser was generated from a 15W LD pumped 0.5%Nd:YVO4 with
intracavity KTP.
200mW green outputs are generated from 1 W LD pumped 2%Nd:YVO4 lasers by using LaserStates 2x2x5mm KTP and 3x3x1mm Nd:YVO4.
2-5mw green outputs are generated from 180mw LD pumped 3%Nd:YVO4 and KTP glued crystals. For more details, please refer to Glued Crystals.
 

镀膜
 

◇ Both ends AR/AR-1064/808nm, R<0.2%@1064nm,R<2%@808nm
◇ S1:HR@1064&532 nm,HT808 nm, R>99.8%@1064&532nm,T>90%@808nm
S2:AR@1064&532 nm, R<0.2%@1064nm,R<0.5%@532nm
◇ S1:HR@1064,HT808, R>99.8%@1064nm,T>95%@808nm
S2:AR@1064, R<0.1%@1064nm.
◇ S1,S2 AR-coated, S3:gold/chrome plated.
◇ Both ends AR/AR-1064 nm; S3:AR-808 nm
◇ Other coatings are available upon request.
 

加工能力
 

Common Specification
尺寸公差 (W±0.1mm)x(H±0.1mm)x(L+0.5/-0.1mm) (L≥2.5mm)
(W±0.1mm)x(H±0.1mm)x(L+0.2/-0.1mm) (L<2.5mm)
通光孔径 central 90% of the diameter
面形
≤ Lambda/8 @ 632.8nm (L≥2.5mm)
≤ Lambda/4 @ 632.8nm (L<2.5mm)
波前畸变 ≤ Lambda/4 @ 632.8nm
倒边 ≤0.2mm@45°
崩边 ≤0.1mm
表面光洁度 S/D 10-5
平行度 ≤ 20 arc seconds
垂直度 ≤ 5 arc minutes
角度公差 ≤ 0.5°
损伤阈值[GW/cm ]:  >1 for 1064nm, TEM00, 10ns, 10Hz (AR-coated)
保质期 One year under proper use