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Nd: YVO4
Nd:YVO4 is the most efficient laser crystal for diode-pumped solid-state lasers. Its good physical, optical, and mechanical properties make it an excellent crystal for high power, stable, and cost-effective diode-pumped solid-state lasers. |
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If we compare the Nd:YVO4 with the Nd:YAG, we find that the Nd:YVO4 possess:
- Lower lasing threshold and higher slope efficiency
- Large Stimulated emission cross-section at lasing wavelength
- High absorption over a wide pumping wavelength bandwidth
- Low dependency on pumping wavelength and tend to single mode output
- Optically uniaxial and large birefringence emit strongly-polarized laser
Basic Properties
Atomic Density: 1.26x1020 atoms/cm3 (Nd 1.0%)
Crystal Structure: Zircon Tetragonal, space group D4h-I4/amd
a = b = 7.1193, c = 6.2892
Density: 4.22g/cm3
Mohs Hardness: 4-5
Thermal Expansion Coefficient (300K): aa = 4.43x10-6/K, ac = 11.37x10-6/K
Thermal Conductivity Coefficient (300K): up C: 0.0523W/cm/K, deg C: 0.0510W/cm/K
Optical Properties: (for 1.1 atm% Nd:YVO4, a-cut)
Lasing Wavelength: 1064nm, 1342nm
Thermal Optical Coefficient (300K): dno/dT = 8.5x10-6/K, dne/dT = 2.9x10-6/K
Stimulated Emission Cross-Section: 25x10-19cm2 @ 1.064m
Fluorescent Lifetime: 90ms
Absorption Coefficient: 31.4cm-1 @ 810nm
Intrinsic Loss: 0.02cm-1 @ 1064nm
Gain Bandwidth: 0.96nm @ 1064nm
Polarized Laser Emission: p polarization; parallel to optic axis (c-axis)
Diode Pumped Optical to Optical Efficiency: > 60%
Sellmeir Equations for Pure YVO4 Crystal:
no2 = 3.77834 + 0.069736 / (λ2 - 0.04724) - 0.0108133λ2
ne2 = 4.59905 + 0.110534 / (λ2 - 0.04813) - 0.0122676λ2
Laser Properties:
The Nd:YVO4 crystal has large stimulated emission cross-sections at both 1064nm and 1342nm. The stimulated emission cross-section of an a-axis cut at 1064nm is about 4 times higher than that of the Nd:YAG crystal. However the lifetime of Nd:YVO4 is about 2.7 times shorter than that of Nd:YAG. Because of its high pump quantum efficiency, the slope efficiency of Nd:YVO4 can be very high if the laser cavity is properly designed. The table below lists the major laser properties of Nd:YVO4 in comparison to the properties of Nd:YAG.
Laser Crystal |
Doping (atm%) |
s (x10-19cm2) |
a (cmx10-1) |
T (ms) |
L (mm) |
Pth (mW) |
hs (%) |
Nd:YVO4 (a-cut) |
1.0 |
25 |
31.2 |
90 |
0.32 |
30 |
52 |
2.0 |
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 and KTP Green Laser |
Nd:YVO4 (mm3) |
KTP (mm3) |
Pump Power |
Output (TEM00 at 532nm) |
3x3x1
|
3x3x5 |
890mW |
76mW |
3x3x1 |
3x3x5 |
50mW |
2.5mW |
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A threshold of 78mW and a slope efficiency of 48.5% at 1.064mm was obtained by using an a-cut 3mm long Nd:YVO4 crystal with output coupler R = 96%. Under the same conditions, a 5mm long Nd:YAG crystal has a threshold of 115mW and a slope efficiency of 28.6%
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Recently, over 30W of TEM00 output power was achieved by using an a-cut Nd:YVO4 and pumped by 60W fiber coupled diode lasers. The optical conversion efficiency exceeds 50%. High power and stable infrared output @ 1064nm and 1342nm has been achieved with diode pumped Nd:YVO4 lasers.
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Single-longitudinal-mode oscillation of a Nd:YVO4 microchip laser has been achieved with high power and high slope efficiency. Such a single mode source has been developed for the use of a master oscillator for injection locking of Nd laser systems.
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Because of its large stimulated emission cross section at 1.34mm, Nd:YVO4 is also an efficient laser crystal for diode laser-pumped 1.3mm laser. By using 1mm long Nd:YVO4 crystal and being pumped by an 850mW diode laser at 808nm, a 50mW output at 1.34mm has been observed. Compared to the 34mW output from a 2mm long Nd:YAG
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Nd:YVO4 Specifications
- Transmitting Wavefront Distortion: < 1/4 @ 633nm
- Dimension Tolerance: W-0.1mm x H-0.1mm x L +0.2mm/-0.1
- Clear Aperture: > 90% central area
- Flatness: 1/8 @ 633nm, and 1/4 @ 633nm for thickness < 2mm
- Scratch/Dig code: 10/5 to MIL-O-13830A
- Parallelism: Better than 5 arc minutes
- Perpendicularity: 5 arc minutes
- AR Coating: R < 0.2% @ 1064nm
- HR Coating: R > 99.8% @ 1064nm, T > 95% @ 808nm
- Quality Warranty Period: One year under proper use
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