Modulation of photon echo intensity by pulsed non-uniform magnetic fields

Abstract Modulations of the intensity of a two-pulse photon echo due to a short, rapidly switched, pulsed magnetic field gradient (⋍1 G/mm) applied during the time, 2τ, between echo preparation and detection in YLiF 4 :Er 3+ are described. The echo intensity changes are explained quantitatively by a model in which the pulsed magnetic field, which adds to the 30 kG DC magnetic field, modulates the optical transition frequencies of the echo-producing Er 3+ ions. These ions, because of the gradient in the pulsed field, experience a spatially-dependent phase accumulation that alters the phase mismatching condition.