  This research focuses on a coherently driven four-level atomic medium with
the aim of inducing a negative index of refraction while taking into
consideration local field corrections as well as magnetoelectric cross
coupling, i.e. chirality, within the material's response functions. Two control
fields are used to render the medium transparent for a probe field which
simultaenously couples to an electric and a magnetic dipole transition, thus
allowing one to test the permittivity and permeability of the material at the
same time. Numerical simulations show that a negative index of refraction with
low absorption can be obtained for a range of probe detunings while depending
on number density and the ratio between the intensities of the control fields.
