This paper presents a wide-ranging theoretical and experimental study of nonadiabatic transient phenomena in a $\Lambda$ electromagnetically induced transparency system when a strong coupling field is rapidly switched on or off. The theoretical treatment uses a Laplace transform approach to solve the time-dependent density matrix equation. The experiments are carried out in a ${}^{87}\mathrm{Rb}$ magneto-optical trap. The results show transient probe gain in parameter regions not previously studied, and provide insight into the transition dynamics between bare and dressed states.

• Received 13 September 2001

DOI:https://doi.org/10.1103/PhysRevA.65.053802