Jean Charles Jacques – Sébastien Bax – Nicolas Cortès

07/01/2008

CO2 Lasers

Theory & Conception

Contents

CO2 Lasers Theory

11

2

Introduction

3

1

5

Low power CO2 lasers

High power CO2 lasers

Conclusion

4

5

Introduction1

2

10.6 µm in the Infrared wavelengths

Continuous power capability

High efficiency

Power from some tens of W to few tens of KW

3

2

hvk )21(Ev

BhcJJ )1(Ej

Vibration levels; Energy Storage

Bending mode

Symmetric Stretching mode

Asymmetric Stretching mode

Vibrational energy:

Rotational energy:

CO2 Lasers Theory

4

2 CO2 Lasers Theory

Transfer collision

E=2meV<25meV

Active medium compositionCO2: 10-20%

N2: 10-20%

He: 60-80%

Low power CO2 Laser3

5

Sealed CO2 Laser

Regeneration of CO into CO2

Infrared specific optic

Brewster angled windows

DC Discharge

Low power output

Small size for a CO2 laser

No heavy cost and maintenance

Low power CO2 Laser3

6

Waveguide CO2 Laser

Very small BeO waveguide

High pressure active medium

Brewster angled windows

Radiofrequency pumping

Yield up to 20% higher than others classical CO2 laser

High-quality beam

4 High power CO2 Laser

Fast axial flow lasers

Increase gas flow

Heat exchanger

Convection

1 kW/m

4 High power CO2 Laser

Fast transverse flow lasers

Gas flow controlled by a turbine (100 Torr)

The laser beam crosses the cavity many times

10 kW/m

Poorer beam quality than axial flow lasers

4 High power CO2 Laser

TEA lasers

Transverse excited atmosphere lasers

Electric discharge : few tens of kV

10 atm : broadering effects

10 MW

Conclusion

Wide range of lasers design and outputs spectrum

Low power, High power

Pulsed or continuous mode

Many fields of application Dominate the cutting and welding business

Lower costs than YAG lasers

Infrared wavelength useful in surgery

Military range finding using LIDAR techniques

5