Neodymium-doped yttrium orthovanadate (Nd:YVO<sub>4</sub>) 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:YVO<sub>4</sub> 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&nbsp;nm (other transitions in Nd are available, and can be selected for by external optics).

Basic properties

  • Atomic density: ~1.37×10<sup>20</sup> atoms/cm<sup>3</sup>
  • Crystal structure:
  • zircon tetragonal (tetragonal bipyramidal)
  • space group D<sub>4h</sub>
  • a=b=7.12, c=6.29
  • Density: 4.22 g/cm<sup>3</sup>
  • Mohs hardness: Glass-like, ~5
  • Thermal expansion coefficient:
  • α<sub>a</sub>=4.43×10<sup>−6</sup>/K
  • α<sub>c</sub>=11.37×10<sup>−6</sup>/K
  • Thermal conductivity:
  • parallel to C-axis: 5.23 W·m<sup>−1</sup>·K<sup>−1</sup>
  • perpendicular to C-axis: 5.10 W·m<sup>−1</sup>·K<sup>−1</sup>

Optical properties

  • Lasing wavelengths: 914&nbsp;nm, 1064&nbsp;nm, 1342&nbsp;nm
  • Crystal class: positive uniaxial, n<sub>o</sub>=n<sub>a</sub>=n<sub>b</sub>, n<sub>e</sub>=n<sub>c</sub>,
  • n<sub>o</sub>=1.9573, n<sub>e</sub>=2.1652, at 1064&nbsp;nm
  • n<sub>o</sub>=1.9721, n<sub>e</sub>=2.1858, at 808&nbsp;nm
  • n<sub>o</sub>=2.0210, n<sub>e</sub>=2.2560, at 532&nbsp;nm
  • Fluorescence lifetime (spontaneous emission lifetime) as a function of Nd ions concentration:

{|

|Nd concentration (atom %)||Fluorescence lifetime (μs)@ 1064&nbsp;nm||Reference

|-

|0.4||110||J. Appl. Phys. 49, 5517-5522 (1978).

|-

|1.0||100||Castech web site

|-

|1.1||90||Casix web site

|-

|2.0||50||Casix web site

|}

  • Absorption cross-section at 808&nbsp;nm: 5.5×10<sup>−20</sup> cm<sup>2</sup>
  • Emission cross-section at 1064&nbsp;nm: 30×10<sup>−19</sup> cm<sup>2</sup> (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&nbsp;nm (257&nbsp;GHz) at 1064&nbsp;nm (for 1.1 atm% Nd doped)
  • Absorption coefficients at 808&nbsp;nm for different doping concentrations:

See also

  • Yttrium aluminium garnet (YAG)

References