  High-resolution Fourier-transform spectroscopy using table-top sources in the
extreme ultraviolet (XUV) spectral range is still in its infancy. In this
contribution a significant advance is presented based on a Michelson-type
all-reflective split-and-delay autocorrelator operating in a quasi amplitude
splitting mode. The autocorrelator works under a grazing incidence angle in a
broad spectral range $\mathrm{(10\,nm - 1\,\mu m)}$ 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
resulting in a resolution of $\mathrm{E/\Delta E=2000}$. Its performance for
spectroscopic applications is demonstrated by characterizing a very sharp
electronic transition at $\mathrm{26.6\,eV}$ in Ar gas induced by the
$\mathrm{11^{th}}$ harmonic of a frequency-doubled Yb-fiber laser leading to
the characteristic $\mathrm{3s3p^{6}4p^{1}P^{1}}$ 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.

Atomic Physics;Optics