Squeezed Coherent States in Double Optical Resonance

In this work, we consider a “Λ-type” three-level system where the first transition is driven by a radiation field initially prepared in a squeezed coherent state, while the second one by a weak probe field. If the squeezed field is sufficiently strong to cause Stark splitting of the states it connects, such a splitting can be monitored through the population of the probe state, a scheme also known as “double optical resonance”. Our results deviate from the well-studied case of coherent driving indicating that the splitting profile shows great sensitivity to the value of the squeezing parameter, as well as its phase difference from the complex displacement parameter. The theory is cast in terms of the resolvent operator where both the atom and the radiation field are treated quantum mechanically, while the effects of squeezing are obtained by appropriate averaging over the photon number distribution of the squeezed coherent state.