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1. February 19,2024
Laser Aided Manufacturing and Materials
Processing

2. 2
Outlines
• Determine the number of sub-energy levels of an atom including two
electrons in 2s and 2p
• Summery of last lecture

3. Determine the number of sub-energy levels of an atom
including two electrons in 2s and 2p

4. 4

5. Summery Of Last Lecture

6. 6
1.Principal Quantum Number (n): n = 1, 2, 3, …, ∞
Specifies the energy of an electron and the size of the orbital (the distance from the nucleus of the peak in a
radial probability distribution plot). All orbitals that have the same value of n are said to be in the
same shell (level).
1.Angular Momentum Quantum Number (l): l = 0, ..., n-1.
Specifies the shape of an orbital with a particular principal quantum number. The secondary quantum
number divides the shells into smaller groups of orbitals called subshells (sublevels). Usually, a letter code
is used to identify l to avoid confusion with n:
3.Magnetic Quantum Number (ml): ml = -l, ..., 0, ..., +l.
Specifies the orientation in space of an orbital of a given energy (n) and shape (l). This number divides the
subshell into individual orbitals which hold the electrons; there are 2l+1 orbitals in each subshell. Thus
the s subshell has only one orbital, the p subshell has three orbitals, and so on.
4.Spin Quantum Number (s): S = +½ or -½.
Specifies the orientation of the spin axis of an electron. An electron can spin in only one of two directions

7. 7
LS Coupling

8. 8
The Franck Condon Principle
It states that all electronic transitions, either
downward (via radiation or collisions) or
upward (via excitation or absorption), must
take place in a vertical direction on a diagram
of molecular energy versus atomic separation.
•Electronic transitions take place so rapidly that
internuclear separations do not have time to
change during the transition.

9. 9
How is Laser Working and Generate Specified Energy?

10. 10
Application of Oscillator in Laser

11. 11
Output of the Laser

12. 12
Rate of Excited States

13. 13
Nonradiative decay – collisional decay
Decay time associated with collisional depopulation in
• Molecular gas
• High-density materials
Molecular gas High-density materials
Collisional depopulation of excited atoms
in a gaseous state can occur when
electrons, atoms, or molecules colliding
with the excited species move the
population of that species to another level
(generally a lower level).
Collisional interactions in liquids and
solids are due to rapid shortrange
movements of the closely spaced atoms of
the dense medium, which are vibrating at
velocities associated with the temperature
of the medium

14. 14
Linewidth of a Radiating Electron
This type of emission broadening occurs when every atom of the same species making
the same transition produces an identical emission lineshape and width. Such a situation
leads to the Lorentzian lineshape function and is referred to as homogeneous broadening.

15. 15
Dephasing

16. 16

17. 17
Voigt Lineshape Profile
There are many transitions in gases for which the emission linewidth due to natural
(homogeneous) broadening and that due to Doppler (inhomogeneous) broadening are
comparable or nearly comparable.
The resulting line profile, a combination of Doppler and Lorentzian shapes, is known as a
Voigt profile.

18. 18
Power Comparison

19. 19
Thank You