RESONANCE FLUORESCENCE-SPECTRUM IN A BROAD-BAND SQUEEZED VACUUM - SIDE-BAND NARROWING

We show, in contrast to what has hitherto been believed, that the linewidth of the side peaks in the resonance fluorescence spectrum of an atom interacting with broadband squeezed fields and driven by a strong pump can be reduced below the normal vacuum value. In particular, for squeezing parameter N in the range 0<N<0.125 and relative phase theta=0 we observe narrowing of the linewidth, and for N=0.125 the linewidth is identical to that of the normal vacuum case. For N>0.125, side peaks always broaden.