Coherence and Photons

Yoon‐Seok Lee, Heung‐Ryoul Noh, Han Seb Moon

We investigated the relationship between two- and three-photon coherence in terms of the transition routes and coupling field intensities in a Doppler-broadened ladder-type atomic system for the 5S1/2–5P3/2–5D5/2 transition in 87Rb atoms. Three-photon electromagnetically induced absorption (TPEIA) due to three-photon coherence was observed in the only transition route that exhibited a dominant two-photon coherence effect. We showed that two-photon coherence is a necessary condition for three-photon coherence phenomena. A comparison of the relative magnitudes of the electromagnetically induced transparency and TPEIA as a function of the coupling field intensity revealed that the increase of three-photon coherence was faster than that of two-photon coherence. Considering three-photon coherence in a Doppler-broadened ladder-type three-level atomic system, the relation between two- and three-photon coherence was numerically calculated.

Л.М. Сороко

Yoon‐Seok Lee, Heung‐Ryoul Noh, Han Seb Moon

We investigated the relationship between two- and three-photon coherence in terms of the transition routes and coupling field intensities in a Doppler-broadened ladder-type atomic system for the 5S(1/2)-5P(3/2)-5D(5/2) transition in (87)Rb atoms. Three-photon electromagnetically induced absorption (TPEIA) due to three-photon coherence was observed in the only transition route that exhibited a dominant two-photon coherence effect. We showed that two-photon coherence is a necessary condition for three-photon coherence phenomena. A comparison of the relative magnitudes of the electromagnetically induced transparency and TPEIA as a function of the coupling field intensity revealed that the increase of three-photon coherence was faster than that of two-photon coherence. Considering three-photon coherence in a Doppler-broadened ladder-type three-level atomic system, the relation between two- and three-photon coherence was numerically calculated.

Jan Peřina

José Tito Mendonça, Hugo Terças

Moorad Alexanian

We introduce the set of n-photon coherent states and the set of n-photon squeezed coherent states and study their collapse and revival and compare their behavior with the collapse and revival of the corresponding zero-photon coherent states and zero-photon squeezed coherent states, respectively. The set of n-photon squeezed coherent states (n = 0, 1, 2, ···) forms a basis of the Hilbert state of photons and may be of some interest. We notice that the presence of a few extra photons in the n-photon states as compared to the corresponding zero-photon states makes a large difference in the behavior of their collapse and revival. This indicates the large effect that a few extra photons make in the n-photon states as compared to the corresponding zero-photon states in their collapse and revival.