Resonance fluorescence in a squeezed thermal vacuum

Atom radiation in a squeezed thermal reservoir is studied. We show that, as in the case of a squeezed vacuum reservoir, the two quadratures of the atomic polarization are damped at different rates. When the atom is driven by a coherent field, Eve find that the steady-state polarization depends on the relative phase of the squeezing and the driving field. However, this phase dependence becomes less pronounced when the number of thermal photons increases. The fluorescent spectrum is calculated in the strong-driving-field limit by employing the secular approximation. Properties of the spectrum and the possibility of a subnatural linewidth, are investigated.