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Producing negative permittivity via quantum coherence and local field effect in dense media

A proposal to produce negative permittivity based on the refractive index enhancement and Lorentz–Lorenz local field effect in dense atomic gases is presented. In strongly driving dense two-level atom system, the negative permittivity can be achieved by controlling atom coherence and atomic density. This method will significantly reduce the loss for the propagated optical wave and can be applied to the realization of isotropic single-negative materials in the atomic scale in the optical regime.