Nd: YVO4 crystal belongs to the tetragonal system, positive uniaxial crystal. Nd: YVO4 crystal has actually been extensively identified as an important laser product because its growth in 1966.
Nonetheless, the scientists discovered problems in the scattering centre, absorption colour centre, etc. It is, consequently, impossible to grow top quality crystals of the size needed for a flash pump.
Thankfully, it has exceptional absorption as well as gains to the wavelength of diode radiation. As well as the transmission area is massive. The result laser has great polarization qualities. These are enough to cover the imperfections of its small development size.
1. Advantages
Nd: YVO4 crystal has excellent properties. Compared with another generally utilized Nd: YAG crystal (neodymium-doped yttrium aluminium garnet crystal), its pump broadband is much more extensive. The absorption bandwidth efficiency is greater. The stimulated emission cross-section is much more detailed and has superb advancement worth. Nd: YVO4 crystals are used together with nonlinear optical crystals such as LBO crystals, BBO crystals, KTP crystals, and so on. It can realize frequency-doubling conversion as well as readjust working wavelength. The all-solid-state laser constructed from Nd: YVO4 crystal can output near-infrared light, green light, blue light, ultraviolet light and more.
- At about 808 nm pump transmission capacity, concerning the Nd: YAG 5 times
- Section at 1064 nm of the promoted emission of radiation is an Nd: YAG three times.
- Light damage limit is low, high incline efficiency
- Uniaxial crystal axis, the output of linear polarization
2. Weaknesses
Compared with the standard Nd: YAG crystal, Nd: YVO4 has the advantages of an extra substantial absorption coefficient, greater emission sample, polarization absorption and emission qualities, bigger absorption bandwidth, and also ignorance to the temperature modification of the diode. As a result, it is widely used in LD-pumped solid-state lasers.
Nevertheless, it has a big discharge cross-section and a brief top power life time. The energy storage space ability of Nd: YVO4 is a lot less than that of Nd: YAG. Not conducive to high energy, peak power of the Q – switched pulse output. Their benefits are restricted to constant wave result, high typical control, and high conversion effectiveness. Furthermore, the thermal conductivity of Nd: YVO4 is really tiny, only fifty percent that of Nd: YAG. Consequently, it is not conducive to attaining high-power continuous wave outcome.
3. Apply.
Neodymium-doped yttrium vanadate (Nd: YVO4) crystal is a sort of laser crystal with superb performance, which appropriates for making a laser diode pump, specifically a low-power laser. Compared to Nd: YAG, Nd: YVO4 has a greater absorption coefficient and larger promoted emission cross-section.
Laser diode-pumped Nd: YVO4 crystals are integrated with LBO, BBO, KTP and also other crystals with high nonlinear coefficients. It can accomplish better frequency-doubling conversion effectiveness. It can output near-infrared, green, and blue ultraviolet as well as solid-state lasers.
Nd: YVO4 crystals can be extensively utilized in optical communication, industrial laser handling, laser ranging, semiconductor detection, information storage space, display screen, laser printing, medical inspection, equipment, scientific research and also other fields.
Moreover, Nd: YVO4 diode-pumped solid-state lasers are quickly replacing traditional water-cooled ion lasers and lamp-pumped lasers in the marketplace, especially in regards to miniaturization and also single longitudinal setting result.
In the 21st century, many downstream markets of Nd: YVO4 crystal is booming, and the application series of Nd: YVO4 crystal is regularly expanding with noticeable efficiency benefits.
4. Growth method.
In the 1960s, Nd: YVO4 crystal was established. It was drawn out from sodium metavanadate thaw by the air conditioning approach. The size of the Nd: YVO4 crystal expanded by this method was tiny. Ever since, the growth process of Nd: YVO4 crystal has been put forward, such as the Zhilar method, fire melting method, floating zone development method, Bryman method and pull method. Today, the development techniques of Nd: YVO4 crystal are different. The illustration technique is the mainstream Nd: YVO4 crystal growth procedure, which can expand big, top notch crystals.
4.1 Pulling method.
Nd3+: YVO4, crystal melting point is extremely high (about 1820 ℃), should use gold-dependent crucible development, gold-dependent crucible will certainly be oxidized at heat, should utilize a neutral gas (hydrogen) to shield the crucible.
By doing this, growing in an anoxic atmosphere, the dissolved part will decompose into low-priced vanadium oxide (part of YVO4 will decompose right into YVO3), and also oxygen deficiency will take place in the crystal, causing the generation of the colour centre.
Growing in an oxygen-rich environment will certainly result in severe oxidation of the crucible. The minimized episcopes create incorporations inside the crystal. This will cause solid thaw volatilization, leading to component deviation.
By utilizing various growing ambiences in different stages, the oxygen shortage in the crystal can be supplemented, the volatilization of raw materials can be hindered, the single-phase growth of the crystal can be ensured, and the crystal can not be smudged or scattered because of oxygen shortage due to hypoxia.
