Role of inhomogeneous broadening in lasing without inversion in ladder systems

Vemuri, Gautam; Agarwal, G. S.

doi:10.1103/physreva.53.1060

Cited by 50 publications

(32 citation statements)

References 25 publications

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“…Comparing these figures shows a reduction of EIT window width commensurate with past observations [18]. Furthermore we observe a reduction in transparency and gain due to both the driving-field linewidth effect [16] and Doppler broadening [19]. Despite Doppler broadening, both windows are still evident, and the second window is evidently more robust than the first with respect to Doppler broadening.…”

supporting

confidence: 87%

Double-double electromagnetically induced transparency with amplification

Alotaibi

Sanders

2014

Phys. Rev. A

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We show that an alkali atom with a tripod electronic structure can yield rich electromagnetically induced transparency phenomena even at room temperature. In particular we introduce doubledouble electromagnetically induced transparency wherein signal and probe fields each have two transparency windows. Their group velocities can be matched in either the first or second pair of transparency windows. Moreover signal and probe fields can each experience coherent gain in the second transparency windows. We explain using a semi-classical-dressed-picture to connect the tripod electronic structure to a double-Λ scheme.PACS numbers: 42.50. Gy, 42.50.Ex Electromagnetically induced transparency (EIT) exploits interfering electronic transitions in a medium to eliminate absorption and dramatically modify dispersion over a narrow frequency band with applications including slow light, reduced self-focusing and defocusing [1], and quantum memory [2]. Microscopically, a threelevel Λ electronic structure suffices to explain EIT. Double EIT (DEIT) extends EIT to creating two simultaneous transparency windows, one for a "signal" and the other for a "probe" field, with the aid of a third "coupling" field [3][4][5][6][7]. DEIT is valuable for coherent control and enabling long-lived nonlinear interactions between weak fields, which could enable deterministic all-optical two-qubit gates for quantum computing.Whereas the Λ scheme suffices to explain EIT, DEIT requires at least four levels. The tripod (⋔) scheme [3], which has one upper and three lower levels as shown in Fig 1(a), is one such four-level scheme. This scheme can be reframed in the semi-classical-dressed-picture [8,9] shown in Fig. 1(b), which has two lower (|1 and |3 ) and two upper (|± ) levels after eliminating the strong coupling (c) field.This semi-classical-dressed model of the ⋔ scheme corresponds effectively to a double Λ system, and double Λ schemes have been studied experimentally [10]. With our semi-classical-dressed analogy, we show that this ⋔ electronic structure exhibits rich hitherto-unnoticed EIT phenomena, namely what we now call double DEIT (DDEIT). Our DDEIT phenomenon has the property that both the signal and the probe fields can each have two EIT windows given the right parameter choices.One particular aspect of our system, namely the second EIT window for the probe, has been predicted [11] and observed experimentally [7,12], but this previously observed effect corresponds only to one aspect of our system, namely a double window for the probe and not to our full DDEIT for both signal and probe fields. Moreover, these new second EIT windows for each of the sig- nal and probe fields exhibit coherent gain, which has not previously been expected. We now reprise the dynamics of the driven ⋔ atom [3]. For ≡ 1 andσ ı := |ı |, the free Hamiltonian isĤ 0 = 4 ı=1 ω ı σ ıı . For ω ı := ω ı − ω  , the ⋔ atom is driven by a probe field with frequency ω p = ω 41 − δ p , a coupling field with frequency ω c = ω 42 − δ c , and a signal field with frequency ω s...

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supporting

confidence: 87%

Double-double electromagnetically induced transparency with amplification

Alotaibi

Sanders

2014

Phys. Rev. A

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“…p ] ∂δ p δcen (18) for n g the group index, δ cen the detuning at the center of each window (1 and 2), and ω 0 the transition frequency between levels |1 and |4 . Detuning δ cen equals δ c at the first window and equals δ s at the second window.…”

Section: A Linewidth and Group Velocitymentioning

confidence: 99%

“…Generalizing the choice of atomic propagation direction relative to the direction of the three driving fields would of course lead to different results [18].…”

Section: B Width Of the Transparency Windowsmentioning

confidence: 99%

Slowing the probe field in the second window of double-double electromagnetically induced transparency

Alotaibi

Sanders

2015

Phys. Rev. A

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For Doppler-broadened media operating under double-double electromagnetically induced transparency (EIT) conditions, we devise a scheme to control and reduce the probe-field group velocity at the center of the second transparency window. We derive numerical and approximate analytical solutions for the width of EIT windows and for the group velocities of the probe field at the two distinct transparency windows, and we show that the group velocities of the probe field can be lowered by judiciously choosing the physical parameters of the system. Our modeling enables us to identify three signal-field strength regimes (with a signal-field strength always higher than the probe-field strength), quantified by the Rabi frequency, for slowing the probe field. These three regimes correspond to a weak signal field, with the probe-field group velocity and transparency window width both smaller for the second window compared to the first window, a medium-strength signal field, with a probe-field group velocity smaller in the second window than in the first window but with larger transparency-window width for the second window, and the strong signal field, with both group velocity and transparency window width larger for the second window. Our scheme exploits the fact that the second transparency window is sensitive to a temperature-controlled signal-field nonlinearity, whereas the first transparency window is insensitive to this nonlinearity.

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“…The analysis of the effect of Doppler broadening on EIT was previously presented for a cascade system [23] . Also similar studies on lasing without inversion in three-level A and V-type systems [24] , cascade [25] and four-level systems { 26] were done. These previous works, however, mainly focused on the possibilities of Doppler broadening elimination and preferable configurations (copropagation of probe and drive fields in folded schemes, counterpropagation in a cascade scheme), and not on the transmission widths.…”

Section: Introductionmentioning

confidence: 99%

“…Doppler broadening is usually modeled by the convolution of a given function over Maxwell-Boltzmann velocity distribution. Due to complexity of the integration with a Gaussian distribution, however, explanations of the obtained results usually rely on a numerical analysis [23][24][25][26] . In order to obtain a simple expression of the linewidth, we approximate the usual Gaussian distribution with a Lorentzian function; this leads to rather simple form of the inhomogeneously broadened susceptibility with which a detailed analysis is possible.…”

Section: Introductionmentioning

confidence: 99%

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

2002

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We show for the first time an explicit expression of the linewidth of an EIT resonance in an inhomogeneously broadened three-level A 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 fields 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.

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Role of inhomogeneous broadening in lasing without inversion in ladder systems

Cited by 50 publications

References 25 publications

Double-double electromagnetically induced transparency with amplification

Double-double electromagnetically induced transparency with amplification

Slowing the probe field in the second window of double-double electromagnetically induced transparency

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

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