A two-mode squeezed light based on a double-pump phase-matching geometry

He Xuan-Jian¹, Jia Jun¹, Jiao Gao-Feng¹, Chen Li-Qing^{1, †}, Yuan Chun-Hua^{1, 3, ‡}, Zhang Wei-Ping^{2, 3}

(a) Double-Λ scheme with two pump fields P₁ and P₂ for (a) the frequency non-degenerate and (b) frequency degenerate squeezed lights. States |3⟩ and |4⟩ are orthogonal linear combinations of magnetic states of the excited hyperfine levels. Ω_P₁ and Ω_P₂ are the Rabi frequencies, Δ₁ (=ω_P₁ − ω₃₁) and Δ₂ (=ω_P₂ + δ − ω₄₂) are the detunings, and δ is the two-photon detuning.