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.

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: 1.26×10²⁰ atoms/cm³ (Nd 1.0%)
Crystal Structure: Zircon Tetragonal, space group D_4h-I₄/amd
a = b = 7.1193, c = 6.2892
Density: 4.22g/cm³
Mohs Hardness: 4-5
Thermal Expansion Coefficient (300K): a_a = 4.43×10^-6/K, a_c = 11.37×10^-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): dn_o/dT = 8.5×10^-6/K, dn_e/dT = 2.9×10^-6/K
Stimulated Emission Cross-Section: 25×10^-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:
n_o² = 3.77834 + 0.069736 / (λ² – 0.04724) – 0.0108133λ²
n_e² = 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.

Typical Results

 

Diode Pumped Nd:YVO₄ Laser Output Comparing with Diode Pumped Nd:YAG Laser

 

Diode Pumped Nd:YVO₄ and KTP Green Laser

 

1. 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%
    
2. 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.
    
3. 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.
    
4. 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

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