New Publication in Journal of Physics: Photonics
Members of the CFEL-ATTO group have collaborated with the group of Prof. Roberto Oselame from the Institute for Photonics and Nanotechnologies CNR-IFN in Milan (Italy) to develop a novel differentially-pumped integrated glass chip for the efficient generation of ultrashort UV radiation using Third Harmonic Generation. The results have been published in JPhys Photonics as a contribution to the special issue 'Emerging Leaders 2024'.
Sketch of the differentially-pumped integrated glass chip used for ultraviolet supercontinuum generation. Source: https://iopscience.iop.org/article/10.1088/2515-7647/ad2bd3
Abstract: We investigate the efficient generation of ultra-broadband femtosecond ultraviolet (UV) radiation via third-order harmonic generation in highly confined gas media. A dual-stage differential-pumping scheme integrated into a glass microfluidic chip provides an exceptional gas confinement up to several bars and allows the apparatus to be operated under a high-vacuum environment. UV pulses are generated both in argon and neon with up to ∼0.8 μJ energy and 0.2% conversion efficiency for spectra that cover the UVB and UVC regions between 200 and 325 nm. Numerical simulations based on the unidirectional pulse propagation equation reveal that ionization plays a critical role in extending the spectral bandwidth of the generated third-harmonic pulse beyond the tripled 800 nm driving laser pulse bandwidth. By delivering UV supercontinua supporting Fourier transform limits below 2 fs, as well as comparable pulse energies concerning capillary-based techniques that typically provide high spectral tunability but produce narrower bandwidths, our compact device makes a step forward towards the production and application of sub-fs UV pulses for the investigation of electron dynamics in neutral molecules.
More information can be found here.