  The development of compact and bright XUV and soft X-ray sources based on
high-order harmonic generation is boosting advances towards understanding the
behavior of matter with extreme temporal and spatial resolutions. Here, we
report efficient XUV generation inside microfluidic devices fabricated by
femtosecond laser irradiation followed by chemical etching. Our microfluidic
approach allows one to control and manipulate the generation conditions in gas
on a micro-meter scale with unprecedented flexibility, thus enabling a high
photon-flux and broadband harmonics spectra up to 200 eV.
