1. By Tijmen Rümke

2. Introduction 3 Metal Gas Lasers The Copper Vapor Laser
Theory
Characteristics
Applications
Conclusion
3 Metal Gas Lasers
The Copper Vapor Laser
The Gold Vapor Laser
The Lead Vapor Laser

3. Theory
Introduction
Theory
Characteristics
Applications
Conclusion
Energy-level Arrangements and Pumping and Decay Processes for different laser types:

4. Theory
Introduction
Theory
Characteristics
Applications
Conclusion
Parity -> Higher probability for ground level to upper level transition -> Γ0l, γl0 < Γ0u, γu0.
Radiation Trapping -> γu0, γl0 < γul.

5. Theory Radiation Trapping for decay from upper and lower level.
Introduction
Theory
Characteristics
Applications
Conclusion
Radiation Trapping for decay from upper and lower level.
Nl grows until Nl > Nu.
No Population Inversion!
Laser breaks down.
Depopulation by diffusion to the walls (slow) and collisional decay (1μs)

6. Characteristics Energy Diagrams for the 3 lasers:
Introduction
Theory
Characteristics
Applications
Conclusion
Energy Diagrams for the 3 lasers:
Copper: Yellow (578 nm) and Green (511 nm).
Gold: Far infra-red.
Lead: Red.

7. Characteristics For Copper: Pulses of 10-50 ns, Energy 1 mJ or higher,
Introduction
Theory
Characteristics
Applications
Conclusion
For Copper:
Pulses of ns,
Energy 1 mJ or higher,
Repetition rates up to 100kHz,
Thus, average powers of W
Gain bandwidth of the order of the atomic transition -> Copper’s = 2,3 GHz
Usage time hours.

8. Characteristics For Copper: Cross section for: 511 nm: 8.6∙10-18 m2
Introduction
Theory
Characteristics
Applications
Conclusion
For Copper:
Cross section for:
511 nm: 8.6∙10-18 m2
578 nm: 1.3∙10-17 m2
Inversion Density
ΔN = 8∙1017 m-3
Single Pass Gain

9. Characteristics Gas temperature: 1,500°C Introduction Theory
Applications
Conclusion
Gas temperature:
1,500°C

10. Applications For the Copper Vapor Laser: High Speed Flash Photography,
Introduction
Theory
Characteristics
Applications
Conclusion
For the Copper Vapor Laser:
High Speed Flash Photography,
Particle Image Velocimetry,
Light and Image Shows,
Dermatology Laser Treatment,
Material Processing

11. Applications High Speed Flash Photography:
Introduction
Theory
Characteristics
Applications
Conclusion
High Speed Flash Photography:
Same spray subject, same high speed camera,
But, left is a continuous light source and right is using laser strobe illumination,
Left blurry, Right very sharp.

12. Applications Particle Image Velocimetry:
Introduction
Theory
Characteristics
Applications
Conclusion
Particle Image Velocimetry:
Determination flow parameters over time
Obtaining pictures of flow turbulence

13. Applications Light and Image Shows: Laser shows.
Introduction
Theory
Characteristics
Applications
Conclusion
Light and Image Shows:
Laser shows.
With suitable hard- and software a very large video image can be produced.

14. Applications Dermatology Laser Treatment:
Introduction
Theory
Characteristics
Applications
Conclusion
Dermatology Laser Treatment:
Different vascular and pigmented lesions:
Port wine stains, lentigo, tattoos, post surgical telangiectasias, etc.
Wrinkles reduction and acne treatment.
No side-effects documented!

15. Applications Material Processing:
Introduction
Theory
Characteristics
Applications
Conclusion
Material Processing:
Used to ablate materials in which very precise edges are desired (of about 1 μm):
Identification signs, details, logos, etc

16. Applications For the Gold Vapor Laser: Oncology: Photodynamic therapy:
Introduction
Theory
Characteristics
Applications
Conclusion
For the Gold Vapor Laser:
Oncology: Photodynamic therapy:
Photoabsorptive material accumulates arount cancer tumor cells,
Laser irradiates that area and thus destroys the cancer cells.

17. Conclusion References: The book: Laser Fundamentals, Silvast, 2004
Introduction
Theory
Characteristics
Applications
Conclusion
References:
The book: Laser Fundamentals, Silvast, 2004
Any Questions??