Femtosecond laser micromachining of integrated glass devices for high‐order harmonic generation

Femtosecond laser micromachining is a versatile technique that is broadly used for the fabrication of integrated optics and microfluidic devices. In this work, we present the fabrication and demonstration of a microfluidic device used for high-order harmonic generation in a hollow waveguide filled with helium. We found a higher generation yield and a harmonic spectrum reshaping (at gas baking pressures over 400 mbar) in the hollow waveguide with a smoother surface. We believe that, thanks to the high versatility and three-dimensional capability of this microstructuring technique, in the next future it will be possible to integrate more functionalities in the same glass chip thus paving the way to strong laser field physics in a lab-on-chip.