Resonance fluorescence spectrum of two atoms,coherently driven by a strong resonant laser field

In Lehmberg's approach, we consider the resonance fluorescence spectrum of two radiatively interacting atoms. In the strong field limit we have obtained analytical solutions for the spectrum of the symmetric and antisymmetric modes without decoupling approximation. Our solutions are valid for all values of the distance r₁₂ separating the atoms. The spectrum of the symmetric modes contains additional sidebands in 2Ω (Ω is the Rabi frequency) with amplitude dependent on (a/Ω)², where a is a parameter dependent on r₁₂. The antisymmetric part of the spectrum has no additional sidebands in 2Ω. For small distances r₁₂ (a=1) our results for the symmetric modes are identical with those of Agarwal et al. apart from the so-called scaling factor. For large distances r₁₂ (a=0) the spectra of the symmetric and antisymmetric modes are identical with the well-known one-atom spectrum.