laser technology

1. LASER
Light
Amplification
By Stimulated
Emission of
Radiation

3. Types of Lasers

4. Nd – YAG LASER
Nd – Neodymium
YAG – Yittrium Aluminium Garnet (Y3Al5O12)
Four Level Solid State Laser
Nd – YAG rod: Length 5 to 10 cm & diameter 6 to 9 mm
Principle:
The active medium is Nd – YAG rod. Nd ions are optically
pumped by krypton flash tube to excited state. During transition
from metastable to ground state, it emitts laser of wavelength
1.064 μm.

5. Nd-YAG LASER

6. Energy level diagram of Nd – YAG
Laser

9. Carbon-di-oxide LASER
Carbon-di-oxide is a linear molecule.
Two oxygen atoms are attached with central carbon
atoms on either side.
It undergoes three independent vibrational oscillations
knows as the vibrational modes
(a)Symmetric Mode
(b)Bending Mode
(c)Asymmetric Mode:

10. Principle:
The active medium is Carbon-di-oxide.
Nitrogen atoms are first raised to excited state.
CO2 molecule absorbs energy from nitrogen and raised to
excited state.
During transition from higher energy level to lower
energy level laser is emitted
Construction:
Quartz Discharge tube: Length 5 m and Diameter 2.5 cm
0.33: 1.2 : 7 Hg pressure CO2 : N2 : He

11. Carbon-di-oxide LASER

12. Energy level diagram of CO2 Laser

25. Difference between Homo-junction and
Hetero-junction LASER

27. THANKS