By Tijmen Rümke 12-04-2006

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

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

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.

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)

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.

Characteristics For Copper: Pulses of 10-50 ns, Energy 1 mJ or higher, Introduction Theory Characteristics Applications Conclusion For Copper: Pulses of 10-50 ns, Energy 1 mJ or higher, Repetition rates up to 100kHz, Thus, average powers of 10-100W Gain bandwidth of the order of the atomic transition -> Copper’s = 2,3 GHz Usage time 500-1000 hours.

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 103 - 106

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

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

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.

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

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.

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!

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

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.

Conclusion References: The book: Laser Fundamentals, Silvast, 2004 Introduction Theory Characteristics Applications Conclusion References: The book: Laser Fundamentals, Silvast, 2004 http://www.oxfordlasers.com/imaging/pdfs/prodcvl.htm http://yachroma.com/ http://spectronika.com/Applications.html Any Questions??