Over the years, femtosecond laser-assisted etching (FLAE) gained a lot of fame as process, especially for glass. This is due to its peculiar characteristics, such as (i) the non-thermal interaction with the material, that minimizes collateral damage and prevents heat from spreading to surrounding areas, which is essential for applications requiring micron- or nano-scale precision; (ii) the capability of manufacturing three-dimensional freeform components; (iii) the compatibility with a wide range of substrates, making the process suitable for several industrial and research applications. This thesis work focuses on Ultra-Low Expansion (ULE) and D263T glass, respectively a titanium-doped silicate and a borosilicate glass, chosen for their unique properties and widespread applications in fields such as optics, electronics, and microfabrication.