Abstract
Femtosecond enhancement cavities have enabled multi-10-MHz-repetition-rate coherent extreme ultraviolet (XUV) sources with photon energies exceeding 100 eV - albeit with rather severe limitations of the net conversion efficiency and of the duration of the XUV emission. Here, we explore the possibility of circumventing both these limitations by harnessing spatiotemporal couplings in the driving field, similar to the "attosecond lighthouse," in theory and experiment. Our results predict dramatically improved output coupling efficiencies and efficient generation of isolated XUV attosecond pulses.
Highlights
In recent years, femtosecond enhancement cavities (ECs) have matured to an enabling technology for precision metrology with coherent radiation in the vacuum and extreme ultraviolet (VUV, XUV) spectral regions
We theoretically investigate the effect of the target position on the output coupling (OC) efficiency and the gating efficiency
Because the divergence of the XUV beamlets depends on the harmonic order, intensity and target gas [16], we consider two cases: OC of the 33th harmonic produced in argon (39.9 eV, compare [8]), with a peak intensity of 1.5 × 1014 W/cm2 in the target plane, and of the 79th harmonic produced in neon (95.6 eV, compare [26]), with a peak intensity of 3.0 × 1014 W/cm2
Summary
Femtosecond enhancement cavities (ECs) have matured to an enabling technology for precision metrology with coherent radiation in the vacuum and extreme ultraviolet (VUV, XUV) spectral regions. ECs are passive optical resonators that can be efficiently excited over a broad optical band, usually in the near-infrared (NIR), by the pulse train of a (post-amplified, phase-stabilized) modelocked laser This results in a circulating pulse with an energy enhanced by a few orders of magnitude with respect to that of the seeding pulses, affording intensities high enough to drive high-order harmonic generation (HHG) in gases at repetition rates of several tens of MHz [1, 2]. Geometrically coupling out the harmonic radiation through an on-axis opening in the mirror following the HHG focus [6,7,8] enabled MHz-HHG with photon energies high enough to liberate core electrons from metals via single-photon photoelectron spectroscopy (PES) This led to the first space-charge-free PES experiments at multi-MHz repetition rates [8, 9], in particular with attosecond temporal resolution [8]. These recent advances indicate a vast potential of improving the intracavity conversion efficiency
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
