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 (ηs).
Laser Properties of Nd:YVO4 vs Nd:YAG
|
LASER CRYSTAL |
DOPING(atm%) |
σ
(x10-19cm2) |
α
(cm-1) |
τ
(μs) |
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 |
• 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 LaserMa’s 2x2x5mm KTP and 3x3x1mm Nd:YVO4
LASERMA provides the following coatings
- 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.
LASERMA Warranty on Nd:YVO4 Specifications:
• Dimension tolerance:(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)
• Transmitting wavefront distortion:less than λ/4 @ 633nm
• Clear aperture:>90% central area
• Chamfer: ≤0.2mm@45
• Chip: ≤0.1mm
• Flatness: λ/8 @ 633 nm (L≥2.5mm), λ/4 @ 633nm (L<2.5mm)
• Scratch/Dig code: 10/5 to MIL-PRF-13830B
• Parallelism:better than 20 arc seconds
• Perpendicularity: ≤5 arc minutes
• Angle tolerance:≤0.5°
• Damage threshold[GW/cm2 ]: >1 for 1064nm, TEM00, 10ns, 10Hz (AR-coated)
• Quality Warranty Period:one year under proper use. |
