We numerically investigate the transfer of optical information from a vector-vortex control beam to an unstructured probe beam, as mediated by an atomic vapour. The right and left circular components of these beams drive the atomic transitions of a double-V system, with the atoms acting as a spatially varying circular birefringent medium. Modeling the propagation of the light fields, we find that, for short distances, the vectorial light structure is transferred from the control field to the probe. However, for larger propagation lengths, diffraction causes the circular components of the probe field to spatially separate. We model this system for the D1 line of cold rubidium atoms and demonstrate that four wave mixing can lead to correlations between the optical polarization structure and the diffraction of light, generating coupled dynamics of the internal and external degrees of freedom.
The birefringence of reflection and transmission as well as their corresponding Goos–Hänchen shifts are investigated with complex conductivity in a four level chiral atomic medium. The left circularly polarized (LCP) beam and right circularly polarized (RCP) beam obey the normalization condition
∣R(R,L)∣+∣T(R,L)∣=1 with forward and backward currents as well as coupled driving fields parameters at the interface of a lossy chiral medium of
∣A(R,L)∣≃0 and polystyrene. For the birefringent transmission, the positive GH-shifts are reported while for the birefringent reflection, the negative GH-shifts are measured. The maximum GH-shift in reflections of RCP and LCP beams is measured to
Sr(R,L)=−10λ and that in the transmission is measured to
St(R,L)=10λ with forward and backward currents of complex conductivity. Furthermore, maximum values of GH-shifts in reflection and transmission of LCP beams are calculated to
±40λ and RCP beams are calculated to
±10λ with control field Rabi frequency and backward current variation. The results indicate possible uses in the designing of optical and conductive sensors.
Abstract We propose a scheme for distortion free left/right circularly polarized beams in a chiral atomic medium in a tripod-type configuration using the superposition of atomic states. We measure and control the group index, group velocity and delay and advance times for left/right circularly polarized beams in a transparent chiral atomic medium by varying the population distribution probability in the superposition states. For the left and right circularly polarized beams of the probe field, delay and advance times have been observed at resonance and away from resonance. A negligible distortion and large phase shift in the left/right circularly polarized beams is theoretically investigated in the system. The results show potential applications in telecommunication, cloaking base technology and information processing.