An optical narrowband switch between subluminal and superluminal light propagation in the inverted-Y configuration

Abstract

The propagation of a weak probe field through a four-level inverted-Y type atomic system driven by two additional coherent fields, namely the control field and the repump field, is studied. The simulated probe absorption shows that electromagnetically induced transparency and the line shape of the transparency window under a Doppler-broadened condition are dependent on the residual Doppler averaging due to the wavelength mismatch between the control and probe fields. For 87 Rb the probe propagation changes from subluminal on-resonance under a Doppler-free condition to superluminal on-resonance under a Dopplerbroadened condition. For both 87 Rb and 133 Cs, the narrow subluminal window occurring in the group index profile in a Doppler-free environment offers an excellent delay bandwidth for probe field propagation. Under this condition, the order of the delay in probe field propagation can be as long as a few hundred µs and seems quite promising in the field of optical delay generation and light storage. The analysis shows that the residual Doppler averaging has a greater impact on the switching window under the variation of the Rabi frequency of the control field as compared to that of the repump field.

Study of multi-window electromagnetically induced transparency (EIT) and related dispersive signals in V-type systems in the Zeeman sublevels of hyperfine states of87Rb-D2line

“…Therefore, we may conclude that the Doppler broadening effect leads to the reduction in the magnitude of group indices (n g ) or an increase in the magnitude of group velocities (v g ). This explanation of the Doppler broadening effect is in good agreement with the earlier reported works [41,42,58].…”

“…The group velocity (v g ) of the propagating probe light in an atomic medium can be written as [36,42,58],…”

“…Therefore, the manipulation of the group velocity of light in a medium can be achieved by the observation of narrow EIT and the EIT based steep dispersive signals. Recently, the researchers are focussing on various techniques of manipulation of the group velocity of light in an EIT medium, and many of them have demonstrated subluminal and superluminal propagation of light by changing frequency, intensity and polarization of the applied laser fields [41,42,50,57,58].…”

Electromagnetically induced transparency and Autler-Towns effect in multi-level cascade type system in 133Cs

“…We have also assumed the conservation of population: The effect of thermal averaging can be included in the simulated probe absorption and probe dispersion by assuming the atoms to follow Maxwell velocity distribution. If the probe absorption and probe dispersion are represented by d a and d b respectively under thermal averaging, then they can be written as [24]:…”

Electromagnetically induced transparency and electromagnetically induced absorption in Y-type system

“…Interaction of atom with coherent radiation fields can lead to many interesting physical phenomena like coherent population trapping (CPT), [1][2][3][4] electromagnetically induced transparency (EIT), [5][6][7][8] electromagnetically induced absorption (EIA), [9,10] lasing without inversion (LWI), [11,12] subluminal and superluminal propagation of light, [13][14][15] optical delay generation, [16,17] etc. All these phenomena are expected to have useful applications in future optical devices.…”