This lecture briefly describes the construction and working of Nd:YAG LASER.

1. By
Dr. Arpana Agrawal
Assistant Professor
Department of Physics
(For Master’s students)
Shri Neelkantheshwar Government PostGraduate College, Khandwa, India
UNIT III: Types of LASERS
Lecture II: Solid state laser: Nd:YAG laser
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2. Topics to be covered under Lecture II
• Introduction and Construction
-Active medium
-Pumping method
-Optical resonator
• Working: Energy level diagram
• Advantage and Disadvantages of Nd:YAG LASER
• Applications
• Summary
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3. Solid-state laser, Four-level laser system, and developed by Scientist J.E. Geusic, H.M. Marcos
and L.G. van Vitert in 1964.
Construction
-Active medium: Nd:YAG in the form of cylindrical rod (Y3+  Nd3+ ions)
Nd: Neodymium (rare earth element); YAG: Yttrium Aluminum Garnet: Y3Al5O12
-Pumping method: Optical pumping using Xenon/Krypton flash lamp
-Optical resonator: Ends of the rod are polished to act as optical resonator mirrors. Rod and flash
lamp are enclosed inside an ellipsoidal reflector, with rod at one of its foci and flash lam at other
foci, to ensure the entire flash radiation to focus on laser rod
Introduction and Construction
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4. Working: Energy level diagram
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5. Advantages-
• It has high energy output.
• It has very high repetition rate operation
• It is much easy to achieve population inversion.
Disadvantages-
• The electron energy level structure of Nd in YAG is complicated.
Advantages and Disadvantages of Nd:YAG LASER
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6. • It finds many applications in range finders and illuminators
• It is widely used in engineering applications such as resistor, trimming
scribing, micro machining operations as well as welding, drilling etc.
• It finds many medical applications such as endoscopy, urology, neurosurgery,
ENT, gynecology, dermatology, dental surgery and general surgery.
• Used in light-matter interaction studies; primarily Nonlinear optics,
Harmonic generations etc.
Applications
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7. Type Solid state laser, Four level laser system
Active medium Nd:YAG
Active centre Nd3+ ion
Pumping method Optical pumping
Pumping source Flash lamp of Xenon or Krypton
Optical resonator Two ends of Nd: YAG rod is polished with silver (one end is
fully silvered and the other is partially silvered); elliptical
reflector
Output power approximately 70 watt.
Nature of the output Pulsed or continuous
Wavelength emitted 1.064 µm (infra-red)
Summary
Thank you
Lecture III: Gas LASER: He-Ne Laser (to be Contd…)
16-04-2020