Neodymium-doped yttrium orthovanadate

Neodymium-doped yttrium orthovanadate (Nd:YVO₄) is a crystalline material formed by adding neodymium ions to yttrium orthovanadate. It is commonly used as an active laser medium for diode-pumped solid-state lasers. It comes as a transparent blue-tinted material, which varies to purplish depending on lighting, similar to alexandrite. It is birefringent, therefore rods made of it are usually rectangular.

As in all neodymium-doped laser crystals, the lasing action of Nd:YVO₄ is due to its content of neodymium ions, which may be excited by visible or infrared light, and undergo an electronic transition resulting in emission of coherent infrared light at a lower frequency, usually at 1064 nm (other transitions in Nd are available, and can be selected for by external optics).

Basic properties

• Atomic density: ~1.37×10²⁰ atoms/cm³
• Crystal structure:
• zircon tetragonal (tetragonal bipyramidal)
• space group D_4h
• a=b=7.12, c=6.29
• Density: 4.22 g/cm³
• Mohs hardness: Glass-like, ~5
• Thermal expansion coefficient:
• α_a=4.43×10^{−6}/K
• α_c=11.37×10^{−6}/K
• Thermal conductivity:
• parallel to C-axis: 5.23 W·m^{−1}·K^{−1}
• perpendicular to C-axis: 5.10 W·m^{−1}·K^{−1}

Optical properties

• Lasing wavelengths: 914 nm, 1064 nm, 1342 nm
• Crystal class: positive uniaxial, n_o=n_a=n_b, n_e=n_c,
• n_o=1.9573, n_e=2.1652, at 1064 nm
• n_o=1.9721, n_e=2.1858, at 808 nm
• n_o=2.0210, n_e=2.2560, at 532 nm
• Fluorescence lifetime (spontaneous emission lifetime) as a function of Nd ions concentration:

• Absorption cross-section at 808 nm: 5.5×10^{−20} cm²
• Emission cross-section at 1064 nm: 30×10^{−19} cm² (Reference: JOSA 66, 1405-1414 (1976).)
• Polarized laser emission: π-polarization; parallel to optic axis (c-axis) (for a-cut crystal)
• Gain-bandwidth: 0.96 nm (257 GHz) at 1064 nm (for 1.1 atm% Nd doped)
• Absorption coefficients at 808 nm for different doping concentrations:

See also

• Yttrium aluminium garnet (YAG)

References