Vineet Bharti

Electromagnetic induced transparency in the Doppler broadened cascade transition with multiple excited levels

A theoretical model using the density matrix approach has been presented to show the influence of multiple excited states on electromagnetically induced transparency (EIT) in a cascade-type Doppler broadened medium. A five-level system has been considered that is a simple case of the 87Rb atom. In a room temperature vapour, when the Doppler broadening is comparable with hyperfine splitting in the middle states, there is a strong reduction in EIT. By performing the thermal averaging in the five-level Doppler broadened system, we observe an asymmetric transparency that has already been shown in most of the experimental work.

Study of a four-level system in vee + ladder configuration

We present the results of a theoretical study of a four-level atomic system in vee + ladder configuration using a density matrix analysis. The absorption and dispersion profiles are derived for a weak probe field and for varying strengths of the two strong control fields. For specificity, we choose energy levels of Rb-87, and present results for both stationary atoms and moving atoms in room temperature vapor. An electromagnetically induced absorption (EIA) peak with negative dispersion is observed at zero probe de-tuning when the control fields have equal strengths, which switches to electromagnetically induced transparency (ET) with positive dispersion (due to splitting of the EIA peak) when the control fields are unequal. There is significant linewidth narrowing in thermal vapor

Sub- and super-luminal light propagation using a Rydberg state

We present a theoretical study to investigate sub-and super-luminal light propagation in a rubidium atomic system consisting of a Rydberg state by using density matrix formalism. The analysis is performed in a 4-level vee+ladder system interacting with a weak probe, and strong control and switching fields. The dispersion and absorption profiles are shown for stationary atoms as well as for moving atoms by carrying out Doppler averaging at room temperature. We also present the group index variation with control Rabi frequency and observe that a transparent medium can be switched from sub-to super-luminal propagation in the presence of switching field. Finally, the transient response of the medium is discussed, which shows that the considered 4 level scheme has potential applications in absorptive optical switching.

Polarization-dependent tuning of the Hanle effect in the ground state of Cs

We demonstrate that the Hanle effect can be tuned between magnetically induced absorption (MIA) and magnetically induced transmission (MIT) simply by changing the polarization of the input laser beam. The experiments are done using closed hyperfine transitions of the

Wavelength mismatch effect in electromagnetically induced absorption

\rm D_2

Role of dressed-state interference in electromagnetically induced transparency

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Optical properties of an inhomogeneously broadened Lambda V-system with multiple excited states

{\rm ^{133}Cs}

Coherent population trapping (CPT) versus electromagnetically induced transparency (EIT)

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Optical properties of an inhomogeneously broadened multilevel V-system in the weak and strong probe regimes

F_g = 3 \rightarrow F_e = 2

Polarization-rotation resonances with subnatural widths using a control laser

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