Echo-spectroscopy of dense Yb vapors

This paper presents the results of transient process investigations in Yb vapors after one- and two-pulse excitations. Transient-four-wave-mixing scheme of excitation including angular photon echo conditions are considered. Spatio-temporal and spectral properties of observed signals are studied. Theoretical interpretation of results includes the local field, excitation induced decay and shift corrections. The situations are analysed when inhomogeneous or homogeneous broadening of spectral line is predominant. The facts of echo signal satellite structure, the signal negative time delay, multiple peaks in the transient-four-wave-mixing spectrum and possibility of echo-like signal observation in homogeneous broadened dense medium have been explained.