1. THE CARBON DIOXIDE LASER
Michael Passens
April 7, 2009

2. Content The Carbon Dioxide Molecule Energy-scheme Power-scheme Set-up
Characteristics
Recent experiment

3. The Carbon Dioxide Molecule
Three normel modes of vibration
Asymmetric stretch mode
Bending mode
Symmetric stretch mode

4. Energy-scheme Vibration energy levels
Each of the Vibration energy level has a set of rotational levels
Selection rules

5. Power-scheme Excitation of Nitrogen vibration by electron impact
Collisional transfer
Laser transition from (0,0,1) to (1,0,0) mode
vibrational energy converted into translational energy by collisions with Helium

6. Set-up Longitudinally excited laser
Works as a conventional gas discharge laser
Water coolant jacket
For a gas temperature above 600K the cross section increases extremely
Low pressure laser
Pulsed and cw laser output

7. Transversely excited laser
High total gas pressures of 1 atmosphere
Much higher energy output per unit volume
Pulsed laser output

8. Characteristics
One of the most powerful and efficient ( up to 30%) laser available
These lasers have produced cw powers of greater than 100 kW and pulsed energies of as much as 10kJ
Is used in the general field of materials processing ( cutting,drilling, etching and so forth)

9. Recent experiment
Will a Bendable Laser Scalpel Make the Cut ( Scientific American/ March 4, 2009)
directing the infrared energy through a flexible fiber tube lined with reflective material
You do not need a series of mirrors
Water absorbs CO2 laser energy well, enabling such devices to make a more precise cut than a normal scalpel

10. Recent experiment