Coherent Resonance Fluorescence Excited by Short Light Pulses

Assuming infinite relaxation times and negligible pulse attenuation, we calculate the ringing produced when a resonant light pulse passes through a medium. These assumptions imply that each atom of the medium is excited identically and will therefore radiate coherently. Two models are used for the atoms of the medium: the classical harmonic oscillator and the two-level quantum-mechanical atom. The validity of the various approximations is discussed in detail.