Optical stimulated nutation echo

Observation of the optical analog of the delayed nutation echo [V. S. Kuz'min et at, Zh. Eksp. Teor. Fiz. 99, 215 (1991) [Sov. Phys. JETP 72, 121 (1991)] recently shown in nuclear magnetic resonance is reported. We call this echo a stimulated nutation, echo (SNE) in analogy to the three-pulse-stimulated echo that is produced from a hole pattern burnt into an inhomogeneous line: In a SNE two-pulse sequence, the first pulse burns a train of holes into the inhomogeneous absorption spectrum and its duration t(p) is stored. After a long delay time the second pulse burns its own train of holes. When coincidence of these holes takes place, the SNE occurs at a time t=t(p) following the start of the second pulse. Thus the second pulse reads exactly the duration of the first pulse. It is shown that for a Gaussian-shaped beam, the echo becomes sharper and well recognizable. This echo may be used for Rabi frequency measurement and spectral diffusion studies.