Study of EIT width, transmission and group delay in inhomogeneously broadened Λ closed Zeeman EIT system

Zeeman electromagnetically induced transparency (EIT) is a phenomenon observed in atomic systems in which the absorption of light at a certain frequency is suppressed by the presence of a second laser beam. In this study, we have investigated the phenomenon of Zeeman electromagnetically induced transparency (EIT) in the D₂ line of 87 Rb atoms at room temperature. Our aim is to generate clean signals in a closed system, which is significantly simpler than the standard EIT due to degenerate levels. In this scenario, EIT can be achieved using a single External cavity diode laser (ECDL) source, eliminating the need to phase-lock two separate lasers. We have analyzed the effect of various parameters, such as transit time, cell temperature, coupling intensity, beam diameter and longitudinal magnetic field on the EIT width, peak transmission and group delay.

Our analytical results indicate that a narrower EIT width of 36kHz and a maximum transmission of 92% can be achieved with a probe beam diameter of 1.5cm. Furthermore, we have also observed a large group delay of 0.3 μs, corresponding to an achievable group velocity of (c/504) m/s<!--[if gte msEquation 12]> style='mso-bidi-font-style:normal'>c style='mso-bidi-font-style:normal'>504 style='mso-bidi-font-style:normal'>m/s.

Based on our findings, we conclude that to achieve a lower EIT width, higher transmission, and large group delay at room temperature, a larger probe beam diameter is beneficial. These results have implications for the manipulation of light in atomic systems and the development of new technologies based on the principles of EIT.