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The properties of glass (e.g., transparency, chemical and thermal inertness) are advantageous for optical, microfluidic, and chemical applications. Additive manufacturing allows the creation of complex geometries and novel functionalities. In contrast to metals and polymers, there are limited options for digitally creating transparent glass geometries. Glass becomes viscous when heated above its transition temperature. This allows a bubble-free forming but requires precise thermal management. Previously explored studies established the deposition of multiple types of glasses using fiber and rod feedstocks. A significant challenge is the speed of the process. Phonon modes in all of these glasses directly absorb CO2-laser radiation (λ = 10.6 μm) with an optical penetration depth of <10 μm [J. Bliedtner, H. Müller, and A. Barz, Lasermaterialbearbeitung: Grundlagen–Verfahren–Anwendungen–Beispiele (Carl Hanser Verlag GmbH Co KG, Munich, Germany, 2013), ISBN:3446429298]. The thermal energy must diffuse through the glass with low thermal conductivity to the interface with the workpiece. Faster deposition rates result in the temperature of the process zone exceeding the evaporation temperature for the material and cause material loss. This study quantifies the material loss due to evaporation for the first time and investigates the use of a CO laser (Coherent J-3-5) for the laser glass deposition process. Lower absorption in silica at the 5.5 μm wavelength of this laser permits much deeper optical penetration into the glass. The effects of surface versus volumetric heating resulting from the choice of laser are experimentally investigated by the deposition of glass fibers with different deposition rates with demonstrations of lower vaporization rates under faster deposition conditions.

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Since their development, carbon monoxide and carbon dioxide lasers have found their indispensable place in industrial and medical applications as well as in research facilities. Since then, beam sources in the infrared range have further developed and combined with various components to exploit their full potential. In this chapter, we present an overview of the functions and applications of CO and CO 2 lasers, as well as suitable optics, materials, and coatings for spatial beam shaping, deflection, and methods for temporal beam modulation. Finally, we present typical micro-processing applications.