THE ASYMPTOTIC-BEHAVIOR OF THE SPECTRUM OF RESONANCE FLUORESCENCE

The spectrum of resonance fluorescence from laser-driven multilevel sy stems is investigated and especially its asymptotic frequency dependen ce in the wings. Analytical results are presented and the transitions within multilevel systems are classified into three categories accordi ng to the asymptotic frequency dependence of their spectra. Under cert ain conditions an arbitrarily fast asymptotic fall-off behaviour of th e spectrum is found which, for intermediately strong driving fields, l eads to subnatural linewidths. Numerical examples are presented to ill ustrate the analytical results.