Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Journal of Physics Conference Series

A new way of broadening the EIT window: Control over subluminal group velocity

Krishna Rai Dastidar, Sulagna Dutta

Published Sep 1, 2009• 2 citations
Publisher

Abstract

The broadening of the Electromagnetically induced transparency (EIT) window can be achieved in a three level closed A system by controlling the strength of incoherent pumping. It has been shown that the presence of homogeneous/inhomogeneous decay facilitates the EIT window broadening. Moreover control over the subluminal group velocity associated with EIT can be achived by manipulating the number density of the molecules. This effect has been demonstrated in a heteronuclear molecule (e.g. LiH).

DOI
10.1088/1742-6596/185/1/012036

Related papers

Broadening of EIT window by incoherent pumping in a three-level Λ system: Effect of homogeneous and inhomogeneous broadening

Krishna Rai Dastidar, Sulagna Dutta

The interplay between dynamically induced coherence (DIC) and spontaneously generated coherence (SGC) can induce electromagnetically induced transparency (EIT) in a three-level closed Λ system. When the contributions from these two coherences are equal in magnitude and opposite in sign at the resonances of both the coherent and probe fields, transparency of the probe light occurs at the resonance with absorption humps away from the resonance. We have demonstrated here that the broadening of the EIT window can be controlled by changing the strength of incoherent pumping. This is a new approach for achieving wide EIT window for lossless and distortionless transmission of light of large spectral width. The most attractive feature of this new method is that the FWHM (full width at half-maximum) of the EIT window is further increased when the broadening due to homogeneous/inhomogeneous decay is taken into consideration. This scheme can be applied in atoms/molecules where SGC can be invoked by dressing two closely spaced levels ( e.g. hyperfine levels in atoms or rovibrational levels in molecules) by an external field. This effect has been demonstrated in a heteronuclear molecule ( e.g. LiH) and examined the role of incoherent pumping for controlling the width of the EIT window in the presence and absence of homogeneous/inhomogeneous decay. The experimental realization of the widening of the EIT window in molecules has been discussed.

Europhysics Letters (EPL)•May 19, 2008•11 citations

Electromagnetically Induced Transparency Window in the System of Four-level Configuration

Wu Han-Hua

The absorption and dispersion properties of an N-type four-level system with Doppler(broadening) effect were investigated.In this system we considered two coherent fields and a probe field.When the second coherent field is absent,this system is a single three-level configuration,and the absorption line is just one clear electromagnetically induced transparency(EIT) window.While the second coherent field exists,there are two EIT windows which become wide and deep with the(coherent) intensity increasing.The position width and absorbance of the transparency windows can be manipulated by adjusting the detuning of the driving field.In addition,we also found that the medium shows a large refractive index at each transparency window,and the group velocity of the probe laser can be reduced.

Journal of Jilin University(Science Edition)•Jan 1, 2006•0 citations

Control of Wave Propagation and Effect of Kerr Nonlinearity on Group Index

Hazrat Ali, Ziauddin Ziauddin, Iftikhar Ahmed

We use four-level atomic system and control the wave propagation via forbidden decay rate. The Raman gain process becomes dominant on electromagnetically induced transparency (EIT) medium by increasing the forbidden decay rate via increasing the number of atoms [G.S. Agarwal and T.N. Dey, Phys. Rev. A 74 (2006) 043805 and K. Harada, T. Kanbashi, and M. Mitsunaga, Phys. Rev. A 73 (2006) 013803 ]. The behavior of wave propagation is dramatically changed from normal (subluminal) to anomalous (superluminal) dispersion by increasing the forbidden decay rate. The system can also give a control over the group velocity of the light propagating through the medium via Kerr field.

Communications in Theoretical Physics•Jul 1, 2013•10 citations

The incoherent pump rate: an optical tool for controlling the probe response and dispersion in a three-level Λ system in the presence of spontaneously generated coherence

Sulagna Dutta

The probe response and dispersion of a three-level closed ? system considering spontaneously generated coherence (SGC) have been investigated with and without an incoherent pumping. One can get electromagnetically induced transparency (EIT) whatever be the value of the SGC parameter and phase difference when an incoherent pump is absent. But by turning the incoherent pump rate on, one can control the light propagation from subluminal to superluminal and also the nonlinear response from EIT to electromagnetically induced absorption (EIA) by controlling the SGC parameter and phase difference. Using the incoherent pump rate as an optical tool, the desired configuration around the resonance can be realized. Exact analytical expressions for the coherences in the steady-state limit have been derived in the absence of an incoherent pump rate (keeping all orders of the system parameters) to generalize the analysis, and any restriction on the system parameters has been avoided to make it applicable to various atomic and molecular systems.

Physica Scripta•Dec 13, 2010•12 citations

Effects of inhomogeneous line broadening on electromagnetically induced transparency (EIT) and slow group velocity

Elena Kuznetsova, Olga A. Kocharovskaya, Marlan O. Scully

We show for the first time an explicit expression of the linewidth of an EIT resonance in an inhomogeneously broadened three-level (Lambda) system, and the conditions for the dependence of the linewidth on a driving field strength. Both gaseous systems with the Doppler effect and solid media in which inhomogeneity of the crystalline field results in a broad distribution of atomic center frequencies are considered. We find two extreme cases: in one extreme the linewidth of EIT resonance is proportional to the intensity of a drive laser. And in the other it is proportional to the Rabi frequency of a drive laser, which recovers the result obtained by Feld and Javan. The dispersive properties of EIT, leading to slow group velocity of light, in an inhomogeneously broadened system are also considered.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Apr 3, 2002•2 citations

Control over group velocity in a three-level closed Λ system via spontaneously generated coherence and dynamically induced coherence

Sulagna Dutta, Krishna Rai Dastidar

The light propagation of a probe field in a three-level Λ system with incoherent pumping has been studied when both dynamically induced coherence (DIC) and spontaneously generated coherence (SGC) play a significant role. We have investigated the group velocity of probe field and hence the group index of a three-level Λ system with incoherent pumping when both DIC and SGC play a significant role. We have shown that by varying the probe field Rabi frequency one can control the interference between these two coherences which leads to different nonlinear response (amplification without inversion, electromagnetically induced transparency and electromagnetically induced absorption) leading to different (positive and negative) dispersion. Hence control over switching of group velocity from subluminal to superluminal and vice versa can be achieved. We have also shown that when the contributions from both the coherences are comparable, the dependence of group velocity of probe field in a three-level Λ system with incoherent pumping on phase difference between probe and coherent fields is different from that obtained under the weak probe field condition. Going beyond the weak probe field approximation we have derived analytical expressions for group velocity and hence the group index in the steady state limit (keeping all orders of system parameters) to generalize the analysis, and these expressions can be used for any set of system parameters without any restriction. The numerical values obtained by solving the density matrix equations agree well with these exact analytical values at a large time limit. We have proposed a scheme for experimental realization of EIT and hence subluminal light propagation in molecules by invoking spontaneously generated coherence.

Journal of Physics B Atomic Molecular and Optical Physics•Oct 22, 2007•21 citations
The broadening of the Electromagnetically induced transparency (EIT) window can be achieved in a three level closed A system by controlling the strength of incoherent pumping. It has been shown that the presence of homogeneous/inhomogeneous decay facilitates the EIT window broadening. Moreover control over the subluminal group velocity associated with EIT can be achived by manipulating the number density of the molecules. This effect has been demonstrated in a heteronuclear molecule (e.g. LiH).
The interplay between dynamically induced coherence (DIC) and spontaneously generated coherence (SGC) can induce electromagnetically induced transparency (EIT) in a three-level closed Λ system. When the contributions from these two coherences are equal in magnitude and opposite in sign at the resonances of both the coherent and probe fields, transparency of the probe light occurs at the resonance with absorption humps away from the resonance. We have demonstrated here that the broadening of the EIT window can be controlled by changing the strength of incoherent pumping. This is a new approach for achieving wide EIT window for lossless and distortionless transmission of light of large spectral width. The most attractive feature of this new method is that the FWHM (full width at half-maximum) of the EIT window is further increased when the broadening due to homogeneous/inhomogeneous decay is taken into consideration. This scheme can be applied in atoms/molecules where SGC can be invoked by dressing two closely spaced levels ( e.g. hyperfine levels in atoms or rovibrational levels in molecules) by an external field. This effect has been demonstrated in a heteronuclear molecule ( e.g. LiH) and examined the role of incoherent pumping for controlling the width of the EIT window in the presence and absence of homogeneous/inhomogeneous decay. The experimental realization of the widening of the EIT window in molecules has been discussed.
The absorption and dispersion properties of an N-type four-level system with Doppler(broadening) effect were investigated.In this system we considered two coherent fields and a probe field.When the second coherent field is absent,this system is a single three-level configuration,and the absorption line is just one clear electromagnetically induced transparency(EIT) window.While the second coherent field exists,there are two EIT windows which become wide and deep with the(coherent) intensity increasing.The position width and absorbance of the transparency windows can be manipulated by adjusting the detuning of the driving field.In addition,we also found that the medium shows a large refractive index at each transparency window,and the group velocity of the probe laser can be reduced.
We use four-level atomic system and control the wave propagation via forbidden decay rate. The Raman gain process becomes dominant on electromagnetically induced transparency (EIT) medium by increasing the forbidden decay rate via increasing the number of atoms [G.S. Agarwal and T.N. Dey, Phys. Rev. A 74 (2006) 043805 and K. Harada, T. Kanbashi, and M. Mitsunaga, Phys. Rev. A 73 (2006) 013803 ]. The behavior of wave propagation is dramatically changed from normal (subluminal) to anomalous (superluminal) dispersion by increasing the forbidden decay rate. The system can also give a control over the group velocity of the light propagating through the medium via Kerr field.
The probe response and dispersion of a three-level closed ? system considering spontaneously generated coherence (SGC) have been investigated with and without an incoherent pumping. One can get electromagnetically induced transparency (EIT) whatever be the value of the SGC parameter and phase difference when an incoherent pump is absent. But by turning the incoherent pump rate on, one can control the light propagation from subluminal to superluminal and also the nonlinear response from EIT to electromagnetically induced absorption (EIA) by controlling the SGC parameter and phase difference. Using the incoherent pump rate as an optical tool, the desired configuration around the resonance can be realized. Exact analytical expressions for the coherences in the steady-state limit have been derived in the absence of an incoherent pump rate (keeping all orders of the system parameters) to generalize the analysis, and any restriction on the system parameters has been avoided to make it applicable to various atomic and molecular systems.
We show for the first time an explicit expression of the linewidth of an EIT resonance in an inhomogeneously broadened three-level (Lambda) system, and the conditions for the dependence of the linewidth on a driving field strength. Both gaseous systems with the Doppler effect and solid media in which inhomogeneity of the crystalline field results in a broad distribution of atomic center frequencies are considered. We find two extreme cases: in one extreme the linewidth of EIT resonance is proportional to the intensity of a drive laser. And in the other it is proportional to the Rabi frequency of a drive laser, which recovers the result obtained by Feld and Javan. The dispersive properties of EIT, leading to slow group velocity of light, in an inhomogeneously broadened system are also considered.
The light propagation of a probe field in a three-level Λ system with incoherent pumping has been studied when both dynamically induced coherence (DIC) and spontaneously generated coherence (SGC) play a significant role. We have investigated the group velocity of probe field and hence the group index of a three-level Λ system with incoherent pumping when both DIC and SGC play a significant role. We have shown that by varying the probe field Rabi frequency one can control the interference between these two coherences which leads to different nonlinear response (amplification without inversion, electromagnetically induced transparency and electromagnetically induced absorption) leading to different (positive and negative) dispersion. Hence control over switching of group velocity from subluminal to superluminal and vice versa can be achieved. We have also shown that when the contributions from both the coherences are comparable, the dependence of group velocity of probe field in a three-level Λ system with incoherent pumping on phase difference between probe and coherent fields is different from that obtained under the weak probe field condition. Going beyond the weak probe field approximation we have derived analytical expressions for group velocity and hence the group index in the steady state limit (keeping all orders of system parameters) to generalize the analysis, and these expressions can be used for any set of system parameters without any restriction. The numerical values obtained by solving the density matrix equations agree well with these exact analytical values at a large time limit. We have proposed a scheme for experimental realization of EIT and hence subluminal light propagation in molecules by invoking spontaneously generated coherence.