Carbon-dioxide laser construction and operation
- The active laser medium is a gas discharge cooled by air or water.
- The filling gas in the discharge tube consists of carbon dioxide, nitrogen, hydrogen, xenon, and helium.
- In flow-through lasers, carbon dioxide is continuously pumped through the discharge tube.
- Electron impact excites quantum vibrational modes of nitrogen, leading to population inversion.
- Carbon dioxide molecules emit radiation at 10.6μm or 9.6μm, maintaining population inversion.
- CO lasers require special materials for construction due to their infrared operation.
- Mirrors are typically silvered, while windows and lenses are made of germanium or zinc selenide.
- Gold mirrors and zinc selenide windows and lenses are preferred for high-power applications.
- Diamond windows and lenses are used in high-power applications and dirty environments.
- Historically, lenses and windows were made of salt, but they degraded with exposure to moisture.

Applications of Carbon-dioxide laser
- Industrial cutting and welding
- Medical surgeries and treatments
- Dermatology and skin resurfacing
- Dental procedures
- Microfluidic systems fabrication

Advantages of Carbon-dioxide laser
- High power output
- Efficient absorption by organic materials
- Precise and controlled ablation
- Minimal thermal damage to surrounding tissues
- Versatile wavelength range

Limitations of Carbon-dioxide laser
- Limited portability due to size and weight
- Higher cost compared to other laser types
- Safety concerns regarding eye protection
- Limited penetration depth in tissues
- Potential for scarring and pigmentation changes in skin resurfacing

CO2 Laser in scientific research and advancements
- Vibrational-rotational transitions of CO2 molecule
- Bidimensional codes recorded on glass surfaces
- Mechanisms of pulsed laser ablation of biological tissues
- Tissue effects of light from surgical lasers
- Mode-to-mode vibrational energy transfer in CO2 collisions
- Continuous-wave CO2 lasers
- High-power CO2-He lasers
- Tunable CO2 lasers
- Beam homogenizer and laser beam profiler
- Carbon-based curtain for stray laser light absorption