Two-time photon correlations in resonance fluorescence

S. Swain

Th. Richter

Dmitri Smirnov, A. S. Troshin

Katsuji Kaminishi, Rajarshi Roy, Robert W. Short +1 more

Alain Aspect, G. Roger, Serge Reynaud +2 more

A new type of time correlation analysis of resonance fluorescence is presented. A strontium atomic beam is excited by a 28-\AA{}A-off-resonance laser. The photons of the two sidebands of the fluorescence triplet are shown to be emitted in a well-defined time order. A simple interpretation of this effect is given which implies a quantum jump of the atom from the lower to the upper state through a multiphoton process.

L. Knöll, G Weber, Thorwirth Sven Schäfer

Using the concept of the time-dependent physical spectrum introduced by Eberly and Wodkiewicz (1977) the authors develop the theoretical basis of time-resolved correlation spectroscopy. The corresponding measuring device consists of two coupled photodetectors with frequency resolving equipment in front of each. A formula is presented for the time-resolved correlation spectrum depending on two time and two frequency arguments. It may be used to gain insight into the time correlation of photons with given frequencies. The authors apply the theory to the resonance fluorescence radiation of a two-level atom irradiated monochromatically. It is shown that in the case of a weak irradiation with large detuning the photons are emitted in a definite time order into the two sidebands of the fluorescence triplet. Under strong resonant irradiation the photons show up bunching (antibunching) behaviour if they belong to different (equal) sidebands. In addition to these results which are already known the authors present new results concerning intermediate situations.