Transmission and dispersion management of room-temperature atomic vapor medium of ^85 Rb using EIT protocol

In this experimental work, we have studied electromagnetically induced transparency (EIT) phenomena in ^85 Rb atomic vapor medium in ladder system. In a novel experimental setting, probe light interacts with a vapor cell before being separated into two orthogonal components with the aid of a polarizing beam splitter (PBS). These orthogonal components are analyzed with varying degrees of probe polarization. A control over transmission and dispersion curve is obtained by changing the linear polarization state of the probe light beam with the help of half-wave plate (HWP) and quarter-wave plate before interaction with the atomic medium. By changing the probe’s polarization state in relation to the coupling polarization, we were able to significantly increase the contrast of EIT signal and relative gain in the dispersion slope. We observed a transition in the dispersion profile from normal to anomalous in the transmitted signal from PBS while varying the HWP angle. Observations made in this paper have potential application towards group velocity manipulation, storage of quantum information, precision measurement, and optical switching.