TIME-REVERSAL DURING MAGNETIZATION OF GAS ATOMS BY A RESONANT LIGHT-PULSE

The optically induced magnetic moment of a stationary atom is calculat ed as a function of time and the resonance detuning omega-omega(ba) to within a constant factor having the dimensions of a magnetic moment b ased on the symmetry of an atom in the field of a resonant light pulse and symmetry with respect to time reversal including the initial cond itions. The even dependence of the optically induced magnetic moment o n omega-omega(ba) for an elliptically polarized pulse with an isotropi c initial state of the atom and its odd dependence on omega-omega(ab) in the case of a linearly polarized pulsed with an anisotropic initial state in the atom's alignment are shown to be consequences of symmetr y with respect to time reversal and the initial conditions. This behav ior is retained even after passage of the light pulse, when the result ing relaxation destroys the time reversal symmetry. The optically indu ced magnetization of an atomic gas is found to have analogous properti es. (C) 1997 American Institute of Physics.