Amplitude-squared squeezing in two-atom resonance fluorescence

Abstract

Amplitude-squared squeezing (ASS), defined recently by Hillery, is extended to atomic dipole operators and considered for resonance fluorescence from two interacting atoms. It is shown that amplitude-squared squeezing, which does not appear in the one-atom case, can occur in two-atom resonance fluorescence. A considerable amount of ASS is obtained for small detuning and large interatomic separations. As interatomic separation decreases, dipole-dipole interaction between the atoms increases and ASS shifts to the region of larger detuning but its value strongly decreases. For very strong dipole-dipole interaction or for very large detuning, the ASS tends to zero. Moreover, it is found that the ASS is directly connected with photon antibunching and can be measured by correlation techniques. The connection between ASS in the atomic variables and ASS in a fluorescent field is also discussed.