ANALYTIC EXPRESSIONS FOR AUTLER-TOWNES TRANSITIONS IN THE PRESENCE OFA LINEARLY POLARIZED PUMP FIELD

Analytic expressions for the peak positions and pump frequency shift o f equal intensity weak probe Autler-Townes transitions to a third leve l 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 dres sing of the strongly excited two levels. A comparison of the Bloch-Sie gert 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-reson antly drives the probe transition! additional light shifts occur which may dominate the Bloch-Siegert shift.