This cylindrical rod (laser rod) and a pumping source (flash tube) are placed inside a highly (reflecting) elliptical reflector cavity. The laser transition takes place between the vibrational states of CO 2 molecules. It is a solid state and 4 level system as it consists of 4 energy levels. The optical resonator is formed by using two external reflecting mirrors. The electrons in the lower energy level need some extra energy to jump into the higher energy level. Because of these properties, lasers are used in a wide variety of applications in all walks of life. In certain cases these lasers are also used to treat eye floaters. It is a four level solid state laser. 4. Then the Nd ions get raised to higher energy levels and their transition produces a laser beam. PRINCIPLE. Nd stands for Neodymium (rare earth element) and YAG stands for Yttrium Aluminum Garnet ( Y3Al5 O12) . An  ion  makes  a  spontaneous  transition  from  E2  to  E1,  emitting  a photon of energy hγ. It is widely used in engineering applications such as resistor, trimming scribing, micro machining operations as well as welding, drilling etc. Strong dual cooling system - Skin Cooling System (SCS) and Contact Cooling System - … * How does Nd:YAG laser work? PRINCIPLE. The long pulsed Nd; Yag has also been successful in treating common skin conditions. The active medium Nd: YAG rod is optically pumped by Krypton flash tubes. While the other end is partially coated in order to provide a path for the light ray from an external source to reach the active medium. Theelectrons orbiting very close to the nucleus are at the lower energy level or lower energy state whereas the electrons orbiting farther away from the nucleus are at the higher energy level. Definition: Nd:YAG laser is the short form used for Neodymium-doped Yttrium Aluminium Garnet. Wavelength of the output: The wavelength of the output beam is 1.06μm(infra-red), 2. The energy state E3 is the metastable state and exhibits longer lifespan. and tested using computer simulation (figure 1). Figure 2.18 shows the energy level diagram for Nd: YAG laser. ; it contains 4 energy levels. However, since all tattoos are not the same in terms of colour, depth of ink deposition and their chemical composition, some may respond differently to others. Also, the doping concentration is around 0.725% by weight. Copyright © 2018-2021 BrainKart.com; All Rights Reserved. Thereby forming an optical cavity. Lasers principles In this chapter and the two following ones we shall describe the principle of the operation of lasers, their common features and the properties of the light they emit. This video lecture will explain the Construction, working and uses of Nd YAG laser Therefore, electrons that were excited to this state by the application external pumping will not stay at this state for much longer duration and comes to lower energy state E3 very fastly but without radiating any photon. Study Material, Lecturing Notes, Assignment, Reference, Wiki description explanation, brief detail, Nd: YAG laser: Principle, Construction, Working, Characteristics, Advantages, Disadvantages and Applications. The construction of Nd: YAG laser is as shown in the figure 2.17. Pumping source: Xenon or Krypton flash tube is used as pumping source. One mirror (M1) is 100% reflecting while the other mirror (M2) is partially reflecting. So, in this way electrons by gaining single photon of energy releases the energy of 2 photons. However, initially, electrons in E1 is very much higher as compared to E4. It finds many medical applications such as endoscopy, urology, neurosurgery, ENT, gynecology, dermatology, dental surgery and general surgery. Basically when the external energy source is provided then the electrons from lower energy state moves to higher energy state thereby causing lasing action to take place. Such an account would, in any case, soon be obsolete.    Nd:YAG laser is basically categorized into 3 domains that are the active medium, pumping source and the optical resonator. Q-switched Nd: Yag Laser Tattoo Removal Machine PL-303. 2. It finds many applications in range finders and illuminators. 1999/July 2003 1.2 Four-level system of the Nd-YAG la-ser. The Neodymium ions atoms make a transition from these energy levels E2 by non-radiative transition. Nature of output: The nature of output is pulsed or continuous beam of light. The different wavelengths available (1064mn and 532mn) can target different pigments of different colors. Then the electrons present in the energy state E1 gains energy and moves to energy state E4. Thereby attaining   population inversion. Here, E1 is the lowest energy state while E4 is the highest energy level. This emitted photon will trigger a chain of stimulated photons between E2 and E1. The triply ionised neodymium [Nd(III)] dopant (ie a substance added in minute amounts to another pure substance to alter its conductivity), typically replaces a small fraction of the yttrium ions in the host crystal structure, since the two ions are of similar size. So, for lasing action to take place an external pump source is required. Nd:YAG laser is the short form used for Neodymium-doped Yttrium Aluminium Garnet. This discharge tube is filled with gaseous mixture of CO 2 (active medium), helium and nitrogen with suitable partial pressures. Construction: It consists of a quartz tube 5 m long and 2.5 cm in the diameter. 5. : The nature of output is pulsed or continuous beam, : The wavelength of the output beam is 1.06μm(infra-red), It has very high repetition rate operation. Theory: Advanced Nd: YAG Picosecond Laser System uses very short pulse output mode, instead of thermal effect, by the principle of light mechanical shock wave, pigment is “shattered” into finely granular via focused energy, are more likely to be absorbed by the body metabolism. Nd:YAG lasers are used in ophthalmology to correct posterior capsular opacification, a condition that may occur after cataract surgery, and for peripheral iridotomy in patients with acute angle-closure glaucoma, where it has superseded surgical iridectomy. The Nd: Yag long pulse laser can be used safely on all skin types – type I to VI. Nd: YAG laser is a neodymium based laser. The Q-switched Nd: yag laser tattoo removal machine PL-303, with the optimal 532nm, 1064nm, 1320nm and an extraordinarily short pulse width of only 10ns, is the most precise and safest yag laser tattoo removal treatment and pigmented lesions solutions available.. A high pulse repetition rate and easy spot size (1-6mm adjustable) …    The two ends of the Nd:YAG rod is coated with silver. Nd: YAG laser is a four-level laser system, which means that the four energy levels are involved in laser action. r, e d(t) S.T.C Pulsed Nd-YAG -t t D(t) laser Tissue response 0(t) : temperature Figure 1: Schematic of the self—tuning control principle. Semiconductor Laser : GaAs laser, GaAsP laser. 6. It is a solid state and 4 level system as it consists of 4 energy levels. Laser technology has greatly improved the ability to treat melanocytic lesions and tattoos with the rapidly pulsed Q-switched neodymium: yttrium – aluminium – garnet (Nd: YAG) Laser. The figure below shows the 4 state energy level diagram of Nd:YAG laser: In this way, several electrons on stimulation produce photons thereby generating a coherent laser beam of 1.064 µm. However, as E4 is an unstable state and it exhibits short lifespan. Type: It is a four level solid state laser. 4. 5. high power output during all the pigment procedures. 2. Basically, as a source of optical pumping, xenon or krypton flash tube is taken in its case. 1. Fast repetition rates and large coverage areas allow large areas of the body to be treated quickly. Due to this more number of electrons will be present at the metastable state E3. The Nd-YAG Laser • Now supersedes the ruby as the most common doped insulator laser • Host material is a crystal of yttrium-aluminium-garnate (Y 3 Al 5 O 12), YAG doped with 0.7% by weight of neodymium (Nd3+) ions • Laser emission takes place at 1.064 µm (infra-red) Solid State Lasers * External Energy source * What is Nd:YAG Laser? YAG laser(Nd:YAG) A YAG laser is used for general-purpose marking applications such as marking on plastic and metal workpieces, as well as for machining applications. 1. The active medium in an Nd:YAG laser is a crystal rod of yttrium aluminium garnet (YAG) with the impurity Neodymium (Nd). Nd: YAG laser is a neodymium based laser. It is a solid state and 4 level system as it consists of 4 energy levels. It corresponds to the transition from E. : Optical pumping is employed for pumping action. Physically, it's an Yttrium aluminium garnet crystal, with Neodymium replacing ~1% of the yttrium atoms in the crystal structure, with surrounding optics and supporting electronic systems. 3. A small amount of Yttrium ions (Y3+) is replaced by Neodymium (Nd3+) in the active element of Nd: YAG crystal. It is much easy to achieve population inversion. * What is Nd:YAG Laser? Due to doping, yttrium ions get replaced by the Nd3+ ions. The laser treatment of pigmented lesions and tattoos are based on principle selected photothermolysis. It would also be anticipated that significantly fewer instances of crusting, blistering, pigmentation problems and other adverse epidermal effects would occur with 1064-nm Nd:YAG laser irradiation.      Optical resonator: Two ends of Nd: YAG rod is polished with silver (one end is fully silvered and the other is partially silvered) are used as optical resonator. * What is applications of Nd:YAG Laser? * Optical resonator  After some time, the photon number multiplies more rapidly. A small amount of Yttrium ions (Y3, The optical resonator is formed by using two external reflecting mirrors. Finally, the structure of the self—tuning control (S.T.C.) In Nd:YAG Laser , Nd stands for neodymium ions Nd3+ and YAG for Yttrium Aluminium Garnet(Y3Al5O12 ). Y3Al5O12 ) completely coated with silver the skin conditions mentioned above are raised excited... 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