Microfluidic devices for quasi-phase-matching in high-order harmonic generation

The development of bright eXtreme UltraViolet (XUV) and soft x-ray sources based on high-order harmonic generation is boosting advances toward understanding the behavior of matter on the attosecond timescale. Here, we report a novel approach for efficient XUV generation consisting of the use of microfluidic integrated systems fabricated by femtosecond laser micromachining of glass. Our microfluidic approach allows one to control and manipulate the gas density on a micrometer scale with unprecedented accuracy and micro-structural flexibility. By propagating ultrashort laser pulses inside the microfluidic devices, we demonstrate high photon fluxes and broadband harmonics spectra, up to 200 eV, from tailored gas media. (C) 2022 Author(s).