Some knowledge about excellent Nd: YVO4 crystal
Nd: YVO4 crystal belongs to the tetragonal system, positive uniaxial crystal. Nd: YVO4 crystal has been extensively identified as a necessary laser product given its development in 1966.
However, the scientists discovered defects in the scattering center, absorption color center, and so on. It is, consequently, difficult to expand premium crystals of the dimension required for a flash pump.
The good news is, it has superb absorption and also gains to the wavelength of diode radiation. And also the transmission area is substantial. The outcome laser has great polarization features. These suffice to cover the imperfections of its small development dimension.
Benefits
Nd: YVO4 crystal has excellent properties. Compared to another generally used Nd: YAG crystal (neodymium-doped yttrium aluminum garnet crystal), its pump broadband is much more comprehensive. The absorption bandwidth performance is higher. The promoted emission cross-section is a lot more detailed and also has exceptional development worth. Nd: YVO4 crystals are used along with nonlinear optical crystals such as LBO crystals, BBO crystals, KTP crystals, etc. It can realize frequency-doubling conversion as well as adjust functioning wavelength. The all-solid-state laser constructed from Nd: YVO4 crystal can outcome near-infrared light, green light, blue light, ultraviolet light, and so forth.
- About 808-nm pump bandwidth, concerning the Nd YAG 5 times
- The area at 1064 nm of the stimulated discharge of radiation is an Nd: YAG 3 times.
- The light damage threshold is low, high incline effectiveness
- Uniaxial crystal axis, the output of linear polarization
Weak points
Compared with the typical Nd: YAG crystal, Nd: YVO4 has the advantages of a much more significant absorption coefficient, higher emission random sample, polarization absorption as well as discharge characteristics, bigger absorption transmission capacity, and also insensitivity to the temperature level adjustment of the diode. Consequently, it is widely made use of LD-pumped solid-state lasers.
Nonetheless, it has a huge exhaust cross-section and a short upper power lifetime. The power storage capacity of Nd: YVO4 is much lower than that of Nd: YAG. Their advantages are limited to continual wave output, high ordinary control, and also high conversion performance. Furthermore, the thermal conductivity of Nd: YVO4 is very tiny, only half that of Nd: YAG. For that reason, it is not conducive to achieving high-power continuous wave outcomes.
Apply.
Neodymium-doped yttrium vanadate (Nd: YVO4) crystal is a sort of laser crystal with exceptional performance, which is suitable for producing a laser diode pump, especially a low-power laser. Compared to Nd: YAG, Nd: YVO4 has a greater absorption coefficient and also a larger promoted discharge cross-section.
Laser diode-pumped Nd: YVO4 crystals are combined with LBO, BBO, KTP, and other crystals with high nonlinear coefficients. It can accomplish better frequency-doubling conversion performance. It can result from near-infrared, green, as well as blue ultraviolet, and also solid-state lasers.
Nd: YVO4 crystals can be extensively made use of in optical interaction, commercial laser handling, laser ranging, semiconductor discovery, data storage, screen, laser printing, medical examination, machinery, scientific research as well as other fields.
Moreover, Nd: YVO4 diode-pumped solid-state lasers are swiftly changing standard water-cooled ion lasers as well as lamp-pumped lasers out there, especially in terms of miniaturization as well as single longitudinal mode outcome.
In the 21st century, many downstream markets of Nd: YVO4 crystal is expanding, and also the application variety of Nd: YVO4 crystal is frequently increasing with obvious performance benefits.
Growth method.
In the 1960s, Nd: YVO4 crystal was developed. It was removed from sodium metavanadate melt by the air conditioning approach. The size of the Nd: YVO4 crystal grown by this technique was tiny. Ever since, the growth process of Nd: YVO4 crystal has been put forward, such as the Zhilar method, flame melting method, floating zone growth method, Bryman method, and also pull method. Currently, the development methods of Nd: YVO4 crystal are numerous. The illustration technique is the mainstream Nd: YVO4 crystal growth procedure, which can grow huge, premium crystals.
4.1 Pulling method.
Nd3+: YVO4, crystal melting point is extremely high (about 1820 ℃), have to make use of gold-dependent crucible growth, gold-dependent crucible will be oxidized at heat, need to utilize a neutral gas (hydrogen).
By doing this, growing in an anoxic atmosphere, the dissolved component will decompose right into low-priced vanadium oxide (part of YVO4 will certainly break down into YVO3), and oxygen shortage will take place in the crystal, resulting in the generation of the color center.
Growing in an oxygen-rich atmosphere will result in serious oxidation of the crucible. The lowered episcopes develop incorporations inside the crystal. This will certainly cause solid melt volatilization, resulting in part discrepancy.
By utilizing different growing ambiances in different stages, the oxygen deficiency in the crystal can be supplemented, the volatilization of resources can be hindered, the single-phase growth of the crystal can be assured, as well as the crystal can not be blackened or spread due to oxygen shortage due to hypoxia.
