Metamaterial made of V-type systems from LiH molecules

We build a V-type system from LiH molecule with antiparallel dipole moments by applying a strong laser field to one of the two transitions in the $$\varLambda $$ -type system made of the excited vibrational state $$A¹\varSigma ⁺ (v=1,\,j=1)$$ and the vibrational states of the ground level $$X¹\varSigma ⁺ (v=1,\,j=0)$$ and $$X¹\varSigma ⁺ (v=0,\,j=0)$$ . This has been called previously by us as V-type system of the second kind. In this system, we have magnetic dipole-allowed transitions in addition to the electric dipole-allowed transitions due to the fact that the obtained dressed states have mixed parities. We find that a medium with V-type systems of the second kind from LiH molecule can have a negative refractive index and/or can be a left-handed medium and therefore can be a metamaterial. We determine the incoherent pumping rate $$\varLambda $$ , the probe detuning $$\Delta _p$$ and the relative phase between the probe and coupling field phases $$\phi $$ , for which our medium of molecular systems achieves a negative refractive index and/or both negative electric permittivity and magnetic permeability.