Time reversal of optical nutation signals.

Department ofPhysics, Harvard University, Cambridge, Massachusetts 02318(Received 3 March 1986)Optical nutation signals are found to be modified in interesting ways by a short, intense, excita­tion pulse. In particular, pulses of appropriate character are found to effect a time reversal of theoptical nutation signal, Le., the nutation signal after the short pulse evolves as the mirror image ofthe nutation signal before the pulse. In ideal cases, all dephasing effects resulting from inhomogene­ous broadening are reversed, and a nutation echo occurs when all atoms rephase in the excited state.Various excitation conditions that lead to the time reversal ofoptical nutation signals are considered,and numerical simulations are compared with experimental results. Finally, the rephasing con­sidered here is compared to that observed in the case ofrotary echoes.II. OPTICAL NUTATION