Equation Icon  ∫ ∞ [ ] SF (Ω ) = dt⟨𝒩ˆ F(t) ∘ ˆ𝒩 F(t′)⟩eiΩ(t−t′) =-S𝒳-𝒳(Ω-) + S ℱℱ(Ω ) + 2Re S𝒳-ℱ(Ω-) , (144 ) −∞ |χxx(Ω )|2 χxx (Ω)