ABSTRACT
The study of the carbon dioxide laser and its spectacular portfolio of applications has been the topic of near continuous research and development for most of the past 40 years. Although the physical principles underlying the basic operation of the CO2 laser itself had become known and well understood within about a decade of its invention in 1964 [1], the ensuing three decades has seen huge activity world-wide in the development of diverse technological implementations of the basic laser physics. Many different types of excitation technology have been developed, as well as a wide variety of optical resonator designs required to accommodate the vastly different gain medium architectures and scales which have been invented to exploit the basic excitation physics. This wide diversity of laser technologies developed for CO2 lasers is capable of generating a range of laser beam characteristics that is probably unmatched by any other laser. These have been applied in many important applications to produce considerable practical impact over 40 years in key areas of science, industry, surgery and in the military sector. Moreover, despite the evident reduction in device research on CO2 lasers over recent years, the scale and diversity of these applications, particularly in industrial manufacturing, continues to expand year-on-year despite the growth in competitive technologies such as solid state and power diode array lasers. As a result, despite such ‘competition’, the CO2 laser remains a basic work-horse of the laser industry, particularly where powerful and flexible beam sources are required for industrial applications (see section D1, Materials processing).
