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Related link: Nd: YVO4 Crystal Components 
Nd:YVO4 Crystal 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) |
|
ThermalExpansion 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 |
Nd:YVO4 Crystal 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(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% |
|
Sellemeier equations (λ in um) |
n02=3.77834+0.069736/(λ2-0.04724)-0.010813λ2 ne2=4.59905+0.110534/(λ2-0.04813)-0.012676λ2 |
Nd:YVO4 Crystal Laser Properties:
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 Nd:YVO4 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, Nd:YVO4 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 (ηs).
|
Laser Crystal |
Doping (atm%) |
σ |
α |
τ |
Lα |
Pth |
ηs |
|
(x10-19cm2) |
(cm-1) |
(μs) |
(mm) |
(mW) |
(%) |
||
|
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 |
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 1W LD pumped 2% Nd:YVO4 lasers by using the 2x2x5mm KTP and 3x3x1mm Nd:YVO4.