Femtosecond Selective Laser Etching of Borosilicate Glasses

This thesis presents a comprehensive theoretical and experimental study of ultra-fast laser-assisted micromachining of borosilicate glasses: Schott BOROFLOAT® 33 and EAGLE XG®. BOROFLOAT® 33 is a clear and transparent colorless glass. Its remarkable transmission and its minimal fluorescence intensities over the light spectrum make BOROFLOAT® 33 ideal for different applications in high-performance photonics and microscopy. Since it is highly resistant to attack by chemicals, alkalis, and organic substances, it is powerful for lab-on-a-chip devices where precise control over microfluidic channels is essential. Lastly, its high thermal shock resistance and low thermal expansion yield applications that require good temperature stability. EAGLE XG® glass is a borosilicate glass specifically designed for high-performance LCDs. It is characterized by low surface roughness, remarkable thermal properties, high resistance to chemicals and scratches. It is environmentally friendly as it contains no heavy metals. Because of these properties, EAGLE XG® is widely used in applied optics, as a substrate for optical coatings and optical wave-guides writing. The research encompasses a detailed characterization of the materials' response to femtosecond laser etching, considering both 3D and 2D geometries. Physical mechanisms characterizing the materials' modification and wet-chemical etching behavior are investigated along with the complexity of the physics behind the laser-matter interaction. The study provides insights into how different regimes of fs-laser interaction influence the etching procedure, focusing on optimizing the process for microfabrication purposes.