We report the results of measurements aimed to check the phase lock of time
-delayed, collinear, harmonic pulses and to verify the possibility of perfo
rming Ramsey-like spectroscopy in the XUV. We demonstrate that for harmonic
s of medium order and for the peak intensities available with our laser sys
tem, the generation of collinear phase-locked harmonic pulses is indeed pos
sible and that such pulses can be used to achieve high-resolution spectrosc
opy in the short-wavelength region.