A. Cournoyer, L. Levesque, M. Levesque "Sub-spot-size CO2 laser micromachining of features in fused silica by V-groove etching" Proc. of SPIE, 5578:544-553, 2004
Abstract: Ablation of fused silica using the Gaussian irradiance profile of the TEM00 mode of a CO2 laser is a very efficient way for micromachining features up to ten times smaller than the beam diameter. A series of laser-etched V-grooves sequentially shifted in a given fashion can be used to micromachine simple or structured patterns on the surface of fused silica substrates. Surface gratings with a periodicity of 12 µm were produced using a CO2 laser beam of 100 µm (1/e2) in diameter. Rectangular wells 50 µm wide and 50 µm deep were also micromachined using the same technique with a radius of curvature of roughly 8 µm at the bottom edges. Although the resolution of the periodic pattern is not fully understood, it appears to be partly governed by the amount of material removal by the top portion of the Gaussian beam (tip processing), as well as a carefully controlled shifting of the etched V-grooves on the fused silica substrate. Physical mechanisms that could be at the origin of the V shape of the grooves are also discussed.
View at publisher