Neodymium Doped Yttrium Orthovanadate (Nd:YVO4) Nd:YVO4's advantages over Nd:YAG
l As high as about five times larger absorption efficient over a wide pumping bandwidth around 808 nm (therefore, the dependency on pumping wavelength is much lower and a strong tendency to the single mode soutput)
l As large as three times larger stimulated emission cross-section at the lasing wavelength of 1064nm
l Lower lasing threshold and higher slope efficiency
l As a uniaxial crystal with a large birefringence, the emission is only a linearly polarized.
Kaston Provides:
l Various doping concentration from 0.1% to 3%
l Various size bulk and finished high quality Nd:YVO4 crystals up to Φ35x50mm3 and Φ20x20mm3, respectively;
l 10,000 pcs of Nd:YVO4 devices per month in sizes 3x3x0.5 to 4x4x8 mm
l With quick delivery
l With competitive price
Basic Properties:
| Atomic Density: |
1.26x1020 atoms/cm3 (Nd1.0%) |
| Crystal Structure: |
Zircon Tetragonal, space group D4h-I4/amd
a=b=7.1193A,c=6.2892A |
| Density; |
4.22g/cm3 |
| Mohs Hardness: |
4-5(Glass-like) |
| Thermal Expansion Coefficient(300K): |
αa=4.43x10-6/K
αc=11.37x10-6/K |
| Thermal Conductivity Coefficient(300K): |
//C:0.0523W/cm/K
⊥C:0.0510W/cm/K |
Optical Properties:
| 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: |
90μs |
| 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% |
| Sellemeier equations |
n02=3.77834+0.069736/(λ2-0.04724)-0.010813λ2
ne2=4.59905+0.110534/(λ2-0.04813)-0.012676λ2 |
Laser Properties of Nd:YVO4
1. One of the most attractive character of Nd:YVO4 is, compared with Nd:YAG, it has 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, is also valuable. 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 and 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, what it emits is only a linearly polarized, 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).
Laser Properties of Nd:YVO4 vs Nd:YAG
| LASER CRYSTAL |
DOPING(ATM%) |
σ
(x10-19CM2) |
α
(CM-1) |
τ
(MS) |
Lα
(MM) |
PTH
(MW) |
ηs
(%) |
| Nd:YVO4(a-cut) |
1.0
2.0 |
25
25 |
31.2
72.4 |
90
50 |
0.32
0.14 |
30
78 |
52
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 |
Warranty on Nd:YVO4 Specifications from Kaston:
• Transmitting wavefront distortion:less than λ/4 @ 633nm
• Dimension tolerance:(W±0.1mm)x(H±0.1mm)x(L+0.2mm/-0.1)
• Clear aperture:>90% central area
• Flatness: λ/8 @ 633 nm, and λ/4 @ 633nm for thickness less than 2mm
• Scratch/Dig code: 10/5 to MIL-O-13830A
• Parallelism:better than 20 arc seconds
• Perpendicularity: 5 arc minutes
• Angle tolerance:<±0.5°
• AR coating:R<0.2% at 1064nm
• Quality Warranty Period:one year under proper use
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