We present experiments in the time and frequency domains aimed at confirming the measured mutual phase coherence of time-delayed, collinear harmonic pulses. We show that pairs of phase-locked harmonic pulses of medium order can be generated for peak intensities up to ~1.5 10<sup>14</sup>W/cm<sup>2</sup> in xenon, demonstrating the possibility of performing high-resolution spectroscopy in the extreme ultraviolet with Ramsey-like techniques.
© 2001 Optical Society of America
M. Bellini, S. Cavalieri, C. Corsi, and M. Materazzi, "Phase-locked, time-delayed harmonic pulses for high spectral resolution in the extreme ultraviolet," Opt. Lett. 26, 1010-1012 (2001)