Table-top interferometry on extreme time and wavelength scales

• DOI: 10.1364/oe.446563
• Publication Date: 2021-11-10T12:30:46Z
• Authors: S. Skruszewicz; A. Przystawik; D. Schwickert; M. Sumfleth; M. Namboodiri; V. Hilbert; R. Klas; P. Gierschke; V. Schuster; A. Vorobiov; C. Haunhorst; D. Kip; J. Limpert; J. Rothhardt; T. Laarmann
• Keywords: Atomic Physics (physics.atom-ph); 0103 physical sciences; FOS: Physical sciences; info:eu-repo/classification/ddc/530; 530; 01 natural sciences; Physics - Atomic Physics; Physics - Optics; Optics (physics.optics)

Short-pulse metrology and dynamic studies in the extreme ultraviolet (XUV) spectral range greatly benefit from interferometric measurements. In this contribution a Michelson-type all-reflective split-and-delay autocorrelator operating in a quasi amplitude splitting mode is presented. The autocorrelator works under a grazing incidence angle in a broad spectral range (10 nm – 1 μm) providing collinear propagation of both pulse replicas and thus a constant phase difference across the beam profile. The compact instrument allows for XUV pulse autocorrelation measurements in the time domain with a single-digit attosecond precision and a useful scan length of about 1 ps enabling a decent resolution of E/ΔE = 2000 at 26.6 eV. Its performance for selected spectroscopic applications requiring moderate resolution at short wavelengths is demonstrated by characterizing a sharp electronic transition at 26.6 eV in Ar gas. The absorption of the 11th harmonic of a frequency-doubled Yb-fiber laser leads to the well-known 3s3p64p1P1 Fano resonance of Ar atoms. We benchmark our time-domain interferometry results with a high-resolution XUV grating spectrometer and find an excellent agreement. The common-path interferometer opens up new opportunities for short-wavelength femtosecond and attosecond pulse metrology and dynamic studies on extreme time scales in various research fields.