Switching from EIT to EIA in a four-level N-type atomic system

Kipkorir Cornelius, Dorothy Koki Mringie, Geoffrey Kihara Rurimo +1 more

Rohit Hazra, Md. Mabud Hossain

Abstract A comparative theoretical study of two-photon electromagnetically induced transparency (EIT), absorption (EIA) and three-photon electromagnetically induced transparency (TPEIT), absorption (TPEIA) and their associated dispersion and group index profiles are presented by using a four-level ladder-type system of both stationary and moving 85 Rb Rydberg atoms. We have observed EIT, EIA and their respective positive and negative dispersive slopes under two-photon conditions, while the TPEIT, TPEIA signals and the respective multiple positive and negative dispersive slopes at around zero detuning of the probe field are observed under the three-photon conditions. It is found that the control and manipulation of the coherent optical responses under three-photon conditions are much richer than the two-photon conditions. The group index profiles related to the dispersion of the medium have been studied under both two- and three-photon conditions to compare and explain the optical switching between the subluminal and superluminal modes of propagation for both stationary and moving atomic medium. The influence of the ‘pump’ Rabi frequency on the group index has also been investigated to illustrate the action of optical switching. Finally, the existence of the four-wave mixing (FWM) process due to the action of three optical fields in the EIT medium is also discussed.

Yağız Oyun, Özgür Çakır, S. Sevinçli

Abstract Electromagnetically induced transparency (EIT) and absorption (EIA) are quantum coherence phenomena which result from the interference of excitation pathways. Combining these with Rydberg atoms have opened up many possibilities for various applications. We introduce a theoretical model to study Rydberg-EIT and Rydberg-EIA effects in cold Cs and Rb atomic ensembles in a four-level ladder type scheme taking into account van der Waals type interactions between the atoms. The proposed many-body method for analysis of such systems involves a self-consistent mean field approach and it produces results which display a very good agreement with recent experiments. Our calculations also successfully demonstrate experimentally observed EIT-EIA cross-over in the Rb case. Being able to simulate the interaction effects in such systems has significant importance, especially for controlling the optical response of these.

杜英杰 Du Yingjie, 葛国库 Ge Guoku

Robert J. Bettles

Vikas Singh Chauhan, Rohit Kumar, Dixith Manchaiah +1 more

In the present work, a theoretical and experimental study to enhance electromagnetically induced transparency (EIT) and electromagnetically induced absorption (EIA) signals in an 85 R b atomic vapor medium at room temperature is conducted. Also, switching from EIT to EIA signal at a particular value of the magnetic field is observed. Further, by using circularly polarized coupling light, the dispersion profile of the linearly polarized probe signal is investigated theoretically and experimentally. The nine-level system of 85 R b D2 transition in a ladder-type configuration is fully solved by using the density matrix theory. The simulated results are found in good qualitative agreement with experimental observations. Hence, an experimental setup is developed for (1) achieving enhanced EIT and EIA signal, (2) switching from EIT to EIA, and (3) dispersion measurement. These observations have potential applications towards measurement of the group velocity of light, quantum memory, quantum information, and optical switching.