Some knowledge about excellent Nd:YAG crystal
Nd:YAG crystal, totally called neodymium-doped yttrium aluminium garnet crystal (Nd: Y3Al5O12), yttrium aluminium garnet crystal as its activator, the material of Nd atoms in the crystal is 0.6 ~ 1.1%, comes from the strong laser, can delight pulse laser or continual laser, releasing laser infrared wavelength 1.064 μm.
Short pulse Nd YAG laser has essential applications in laser processing, photoelectric countermeasures, laser varying, laser communication, etc. Specifically, the peak power laser acquired by Q switching is the core gadget in many sophisticated clinical studies and modern scientific tools and equipment.
Neodymium-doped yttrium aluminium garnet (Nd:YAG) laser crystal has the advantages of good optical harmony, mechanical properties, high physical and chemical stability, great thermal conductivity, and so forth.
It has become the main support product for army solid laser innovation and the application direction of tools and high-power lasers. It is referred to as among the “three basic laser crystal products”, which is commonly made use of in commercial, medical, armed forces, and also clinical studies.
Nd:YAG crystal Benefits
Nd:YAG crystal is still one of the most commonly used strong laser tools due to its superb optical and mechanical buildings, easy manufacturing, and low cost. Nonetheless, the research study mostly focuses on the 946nm, 1064nm, and 1319nm wavelength lasers, and the 1123nm laser emission is likewise a fundamental shift.
Nd: YAG crystals have superiors spectral as well as laser property. It is among one the most commonly used laser crystals. Compared with Nd:YVO4 crystal, the former has high thermal conductivity, great mechanical properties, and easy growth.
Nd:YAG crystal can be used directly; Cr YAG Q modulation to obtain peak power and high repeating frequency result. However, because the doping focus of Nd: YAG crystal is reduced and the absorption coefficient is little, it isn’t easy to understand the miniaturization of the laser and improve its effectiveness. Using the cosy ladder method, we have acquired big, highly drugged Nd: YAG crystals, with the mole portion of Nd ions doped up to 2.3.
Nd:YAG crystal Growth method
(1) Lifting method
Tira method:- Czochralsik:- CZ method, a crystal growth method developed by Czochralsik in the year 1917
Fundamental principle: Under a reasonable temperature level area, the lower end of the seed crystal mounted on the seed crystal rod is decreased right into the raw material of the melt. Under the action of the rotary electric motor and also the training system, the seed crystal rod rotates while slowly pulling up.
After several technological phases, such as neck shrinking, shoulder expansion, shoulder turning, equivalent size, ending up, and carrying out, the single crystal with certified geometric form and inner quality is expanded.
1) Advantages of the pulling method:
(a) During the growth of process, it is easy to observing the growth of crystal
(b) The growth of the crystal on a free surface area of the thaw without contact with the crucible considerably reduces the stress and anxiety on the crystal and also prevents nucleation on the crucible wall surface
(c) It is easy to use orientated seed crystals and the “necking” process to acquire full seed crystals and crystals of the desired orientation. The excellent benefit of the pull-up technique is the capacity to expand crystals of higher quality at a faster rate
2) Disadvantages
(a) Possible contamination of the crystal by crucible material.
(b) The melt’s circulation activity, the transmission’s vibration, and temperature change all impact the crystal’s quality.
(2) Bridgman technique
The Bridgman procedure is a typical thaw growth method, normally divided into upright and horizontal Bridgman processes two.
The good Bridgman process, or the crucible descent technique, expands crystals from melting. Generally, when the crucible is lowered in a taking-shape heating system and goes through a region with a large temperature level slope, the melt takes shape in the crucible from an all-time low up into a single crystal. The formation furnace increasing along the crucible can also finish this procedure.
(3) Guided temperature slope method
The guided temperature level ladder technique is a single condensation approach of melt induced by orientated seed crystals. The temperature field of TGT is primarily changed by readjusting the form as well as placement of the graphite home heating body, Mo insulation screen, Mo crucible, the power of the home heating body, and also the flow of circulating cooling water to create a suitable temperature level gradient from all-time low to top
The main application of Nd YAG laser
The Nd:YAG laser has a wavelength of 1064 nm and is not near the absorption peak of oxygenated haemoglobin, which has bad Nd: YAG laser absorption. Nonetheless, its infiltration deepness can reach 8 mm to play a therapeutic role in the deeper part of the hemangioma. According to the different power result modes, Nd: YAG laser can be separated into continuous and pulse kind 2.
Continuous Nd: YAG lasers are generally used yet are non-selective in thermal tissue damage. Continual Nd: YAG laser is widely used in the ent division, gynaecology, and surgery. And also, in dermatology, due to the “bad cosmetic result”, use is extra mindful. Compared to continuous Nd: YAG laser, pulsed Nd: YAG laser is extra consistent with the careful photothermal concept. It can minimize heat damage to the surrounding typical tissue and decrease the occurrence of scars and other negative reactions.
