Description:
- Nd:YVO4(Neodymium Doped Yttrium Orthovanadate)Nd:YVO4 is the most efficient laser crytal for diode pumping among the current laser crystals, especially, for low to middle power, mainly for its absorption and emission features surpassing Nd:YAG.
Introduction
Neodymium Doped Yttrium Orthovanadate (Nd:YVO4) is the most efficient laser host crystal for diode pumping among the current commercial laser crystals, especially, for low to middle power density. This is mainly for its absorption and emission features surpassing Nd:YAG. Pumped by laser diodes, Nd:YVO4 crystal has been incorporated with high NLO coefficient crystals (LBO, BBO, or KTP) to frequency-shift the output from the near infrared to green, blue, or even UV. This incorporation to construct all solid state lasers is an ideal laser tool that can cover the most widespread applications of lasers, including machining, material processing, spectroscopy, wafer inspection, light displays, medical diagnostics, laser printing, and data storage, etc. It has been shown that Nd:YVO4 based diode pumped solid state lasers are rapidly occupying the markets traditionally dominated by water-cooled ion lasers and lamp-pumped lasers, especially when compact design and single-longitudinal-mode output are required.
Nd:YVO4‘s advantages over Nd:YAG
- 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 output)
- As large as three times larger stimulated emission cross-section at the lasing wavelength of 1064 nm.
- Lower lasing threshold and higher slope efficiency.
- As a uniaxial crystal with large birefringence, the emission is only linearly polarized.
Physical properties:
| Atomic Density: | 1.26×1020 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=4.43×10-6/K αc=11.37×10-6/K |
| Thermal Conductivity Coefficient(300K): | //C:0.0523W/cm/K ⊥C:0.0510W/cm/K |
Optical properties:
| Lasing wavelength: | 1064nm,1342nm,914nm |
| 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: | ≥50% |
| 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 |
Laser properties:
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.
| Laser crystal | Doping (atm%) |
σ (x10-19cm2) |
α (cm-1) |
τ (µs) |
Lα (mm) | Pth (mW) |
Effi. (%) |
| Nd:YVO4 (a-cut) |
1.0 2.0 |
25 25 |
23 46 |
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 |
specifications:
| Dimension Tolerance | (W ± 0.1 mm) × (H ± 0.1 mm) × (L + 0.5/-0.1 mm) × (L≧2.5 mm)
(W ± 0.1 mm) × (H ± 0. 1 mm) × (L + 0.1/-0.1 mm) × (L＜ 2.5mm) |
| Orientation | A-cut/C-cut +/-0.5deg. |
| Flatness | λ/8 @ 632.8nm |
| Wavefront distortion | λ/4@ 632.8nm |
| Surface Quality | 10/5 per MIL-PRF-13830B |
| Parallelism | 20 arc sec |
| Perpendicularity | 15 arc min |
| Bevel/Chamfer | <0.2mm@45deg. |
| Chips | <0.1mm |
| Clear Aperture | >90% |
| Coating | AR/HR/PR (IAD, EB, IBS) coating upon customer’s request |
| Quality Warranty Period | One year under proper use |
AOST provides the following coatings
- Both ends AR/AR-1064/808 nm, R<0.2% @1064 nm, R<0.5% @808 nm, or R<0.1% @1064 nm, R<3% @808 nm
- S1: HR-1064/532 nm, HT-808 nm, R>99.8% @1064/532 nm, T>90% @808 nm
- S2: AR-1064/532 nm, R<0.2% @1064 nm, R<0.5% @532 nm
- S1: HR-1064 nm, HT-808 nm, R>99.8% @1064 nm, T>95% @808 nm
- S2: AR-1064 nm, R<0.1% @1064 nm
- S1, S2 AR-coated, S3: gold/chrome plated
- Both ends AR/AR-1064 nm; S3: AR-808 nm
- Other coatings are available upon request
