Nd: YVO4 crystal belongs to the tetragonal system, positive uniaxial crystal. Nd: YVO4 crystal has actually been widely identified as a necessary laser product since its development in 1966.
Nonetheless, the scientists discovered defects in the scattering centre, absorption colour centre, and so on. It is, therefore, difficult to expand top quality crystals of the size required for a flash pump.
The good news is, it has excellent absorption as well as gains to the wavelength of diode radiation. And also the transmission section is massive. The output laser has good polarization features. These suffice to cover the drawbacks of its little development dimension.
Advantages
Nd: YVO4 crystal has superb properties. Compared with another generally made use of Nd: YAG crystal (neodymium-doped yttrium aluminium garnet crystal), its pump broadband is extra substantial. The absorption transmission capacity performance is higher. The promoted exhaust cross-section is extra thorough and also has excellent development value. Nd: YVO4 crystals are made use of combined with nonlinear optical crystals such as LBO crystals, BBO crystals, KTP crystals, etc. It can understand frequency-doubling conversion and readjust working wavelength. The all-solid-state laser made from Nd: YVO4 crystal can result near-infrared light, green light, blue light, ultraviolet light and so forth.
- At regarding 808 nm pump transmission capacity, about the Nd: YAG five times
- Area at 1064 nm of the boosted emission of radiation is an Nd: YAG three times
- Light damages threshold is reduced, high slope performance
- Uniaxial crystal axis, the result of linear polarization
Disadvantages
Compared to the typical Nd: YAG crystal, Nd: YVO4 has the advantages of an extra substantial absorption coefficient, greater emission cross section, polarization absorption as well as exhaust features, bigger absorption data transfer, and ignorance to the temperature level adjustment of the diode. As a result, it is extensively used in LD-pumped solid-state lasers.
Nevertheless, it has a huge exhaust cross-section as well as a brief upper energy life time. The energy storage space capability of Nd: YVO4 is much less than that of Nd: YAG. Not conducive to high power, peak power of the Q – switched over pulse outcome. Their benefits are limited to constant wave output, high ordinary control, and also high conversion efficiency. Additionally, the thermal conductivity of Nd: YVO4 is really small, only fifty percent that of Nd: YAG. As a result, it is not conducive to achieving high-power continuous wave output.
Applications
Neodymium-doped yttrium vanadate (Nd: YVO4) crystal is a sort of laser crystal with superb efficiency, which is suitable for producing a laser diode pump, particularly a low-power laser. Compared with Nd: YAG, Nd: YVO4 has a higher absorption coefficient as well as bigger stimulated exhaust cross-section.
Laser diode-pumped Nd: YVO4 crystals are combined with LBO, BBO, KTP and other crystals with high nonlinear coefficients. It can attain far better frequency-doubling conversion efficiency. It can output near-infrared, green, and blue ultraviolet and solid-state lasers.
Nd: YVO4 crystals can be widely used in optical communication, commercial laser handling, laser ranging, semiconductor discovery, information storage space, screen, laser printing, medical examination, machinery, clinical study and other fields.
Furthermore, Nd: YVO4 diode-pumped solid-state lasers are quickly replacing conventional water-cooled ion lasers and also lamp-pumped lasers on the market, especially in terms of miniaturization and also single longitudinal mode output.
In the 21st century, many downstream markets of Nd: YVO4 crystal is expanding, and the application series of Nd: YVO4 crystal is frequently broadening with apparent efficiency benefits.
Growth method
In the 1960s, Nd: YVO4 crystal was created. It was removed from salt metavanadate melt by the air conditioning method. The dimension of the Nd: YVO4 crystal grown by this approach was little. Since then, the growth process of Nd: YVO4 crystal has actually been advanced, such as the Zhilar method, fire melting method, floating area growth method, Bryman method as well as pull method. Currently, the development techniques of Nd: YVO4 crystal are numerous. The drawing technique is the mainstream Nd: YVO4 crystal development process, which can grow big, high-quality crystals.
Pulling method
Nd3+: YVO, crystal melting point is very high (concerning 1820 ℃), have to utilize gold-dependent crucible development, gold-dependent crucible will certainly be oxidized at heat, should utilize a neutral gas (hydrogen) to safeguard the crucible.
This way, growing in an anoxic environment, the melted component will decompose into low-priced vanadium oxide (part of YVO4 will decompose right into YVO3), and oxygen deficiency will happen in the crystal, causing the generation of the colour centre.
Growing in an oxygen-rich atmosphere will cause serious oxidation of the crucible. The reduced episcopes form incorporations inside the crystal. This will lead to strong thaw volatilization, causing part inconsistency.
By utilizing various growing ambiences in various phases, the oxygen deficiency in the crystal can be supplemented, the volatilization of raw materials can be prevented, the single-phase growth of the crystal can be ensured, and also the crystal can not be blackened or spread because of oxygen shortage due to hypoxia.
