Physical Review A
Analytic expressions for Autler-Townes transitions in the presence of a linearly polarized pump field
John P. D. Martin
Abstract
Analytic expressions for the peak positions and pump frequency shift of equal intensity weak probe Autler-Townes transitions to a third level in the presence of a linearly polarized pump field are given. It is found that the presence of the third level affects the pump field dressing of the strongly excited two levels. A comparison of the Bloch-Siegert shift estimated by this weak probe technique with earlier methods suggests this condition provides a practical method for obtaining the Bloch-Siegert shift for three level systems where the pump field does not directly excite the probe transition. If the pump field off-resonantly drives the probe transition, additional light shifts occur which may dominate the Bloch-Siegert shift.