Nd: YAG crystal
Nd: YAG, fully called neodymium-doped yttrium aluminum garnet crystal (Nd: Y3Al5O12), yttrium aluminum garnet crystal as its activator, the content of Nd atoms in the crystal is 0.6 ~ 1.1%, comes from the solid laser, can thrill pulse laser or continuous laser, giving off laser infrared wavelength 1.064 μm.
Brief pulse Nd YAG laser has crucial applications in laser handling, photoelectric countermeasures, laser varying, laser communication, etc. Especially the peak power laser gotten by Q switching is the core device in many innovative clinical research as well as modern-day clinical tools and tools.
Neodymium-doped yttrium aluminum garnet (Nd: YAG) laser crystal has the advantages of great optical uniformity, mechanical properties, high physical and also chemical security, excellent thermal conductivity, and so on. It has actually ended up being the major assistance material for army solid laser innovation and also the application direction of medium and also high-power lasers. It is referred to as one of the “3 basic laser crystal materials”, which is widely used in commercial, clinical, army, and scientific research study.
Advantages
Nd: YAG crystal is still one of the most widely made use of strong laser tool as a result of its outstanding optical and also mechanical homes, simple manufacturing, as well as affordable. However, the study mostly concentrates on the 946nm, 1064nm, as well as 1319nm wavelength lasers, and also the 1123nm laser discharge is additionally a crucial transition.
Nd: YAG crystals have superior spectral as well as laser properties. It is among one of the most extensively used laser crystals.
Compared with Nd YVO4 crystal, the previous has high thermal conductivity, good mechanical properties, and simple growth, and also Nd: YAG crystal can be used straight; Cr YAG Q modulation to get peak power and also high rep regularity outcome. However, because the doping focus of Nd: YAG crystal is reduced and also the absorption coefficient is little, it is hard to realize the miniaturization of the laser and boost its effectiveness. We have now acquired big, highly doped Nd: YAG crystals utilizing the cozy ladder technique, with the mole fraction of Nd ions doped up to 2.3.
Growth method of Nd:YAG crystal
Lifting method of Nd:YAG crystal
Tira method: Czochralsik: CZ technique, a crystal growth method developed by Czochralsik in 1917.
Fundamental concept: Under an affordable temperature level area, the lower end of the seed crystal installed on the seed crystal rod is reduced into the raw material of the melt. Under the activity of the rotating motor and lifting device, the seed crystal rod rotates while slowly pulling upwards. After numerous technical phases, such as neck diminishing, shoulder growth, shoulder rotation, equal diameter, finishing, as well as pulling off, the solitary crystal with qualified geometric form and interior high quality is expanded.
1) Advantages of the drawing method:
- During the growth process, it is convenient to observe the growth of the crystal
- The growth of the crystal on a free surface of the thaw without contact with the crucible significantly decreases the tension on the crystal and also avoids nucleation on the crucible wall
- It is easy to use orientated seed crystals and the “necking” process to acquire total seed crystals as well as crystals of the preferred alignment. The terrific advantage of the pull-up technique is the capability to grow crystals of higher quality at a faster rate
2) Disadvantages
- Possible contamination of the crystal by crucible product;
- The thaw’s flow activity, the transmission’s resonance, and the temperature change all impact the crystal’s top quality.
Bridgman technique
Bridgman procedure is a common thaw growth method, typically divided into vertical and horizontal Bridgman process 2.
The vertical Bridgman process, also called the crucible descent method, is a method of growing crystals from thaw. Normally, when the crucible is reduced in a taking shape heating system and also passes through an area with a large temperature level gradient, the melt crystallizes in the crucible from the bottom up into a single crystal. The crystallization heating system climbing along the crucible can additionally finish this procedure.
Guided temperature level slope technique
The directed temperature level ladder technique is a solitary condensation approach of melt generated by orientated seed crystals. The temperature field of TGT is primarily adjusted by adjusting the shape as well as position of the graphite heating body, Mo insulation screen, Mo crucible, the power of the heating body, and the flow of flowing cooling water to create an ideal temperature slope from all-time low to top
Main application of Nd YAG laser
The Nd: YAG laser has a wavelength of 1064 nm and is not near the absorption top of oxygenated hemoglobin, which has inadequate Nd: YAG laser absorption. However, its infiltration deepness can reach concerning 8 mm, so that it can play a therapeutic function in the much deeper part of the hemangioma. According to the various power output modes, Nd: YAG laser can be divided right into constant and also pulse type two.
Continuous Nd: YAG lasers are typically made use of yet are non-selective in thermal tissue damages. Continual Nd: YAG laser is extensively utilized in the ent department, gynecology and also surgical procedure. And also in dermatology, as a result of the “not good cosmetic effect”, use is extra careful. Compared to continual Nd: YAG laser, pulsed Nd: YAG laser is extra regular with discerning photothermal theory. It can lower warm damage to the surrounding typical tissue and decrease the event of marks as well as other damaging reactions.
