Controlling slow and fast light switching with a static magnetic field in an inhomogeneous broadening tripod atomic system

The present study addresses light propagation in both the positive- and negative-group-index regimes in a degenerate atomic system with four energy levels. Both the static magnetic field and the Doppler shifts play essential roles. Operating in an electromagnetically induced transparency configuration, we demonstrate that probe absorption characteristics and the group velocity index can be manipulated by combined control of the static magnetic field and two coupling laser fields. By selectively engaging one or both coupling fields, the magnetic field serves as a switching mechanism, toggling the atomic medium's optical behavior between transparent and absorptive states. Consequently, both the magnitude and sign of the group index can be adjusted, transitioning from positive to negative values or the reverse, based on whether the magnetic field is applied or removed. Additionally, temperature significantly influences both the optical properties and group index characteristics of the atomic medium. Given that our proposed system operates at room temperature, it is well-suited to practical experimental conditions and offers potential for deployment in optical storage technologies and quantum information processing applications.