Real-time analysis of two-photon excitation by correlated photons: Pulse-width dependence of excitation efficiency

We theoretically investigate the dynamics of two-photon excitation by correlated photons with energy anticorrelation in terms of how the excitation efficiency depends on incident pulse width. A three-level atomic system having an intermediate state is used to evaluate the efficiency of two-photon excitation. It is shown that for shorter pulses closer to a monocycle pulse the excitation efficiency by correlated photons is enhanced to become 100 times as large as that by uncorrelated photons.