Phase control of gain and dispersion in an open lambda-type inversionless lasing system

Xie, Fan; Ni, Chen; Tian, Shufen; Ma, H.K.; Gong, Shangqing; Xu, Zhizhan

doi:10.1080/09500340500352873

Cited by 18 publications

(6 citation statements)

References 50 publications

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“…We will show here that SGC plays a dominant role in AWI only when the probe field Rabi frequency is orders of magnitude smaller than the coherent field Rabi frequency. Fan et al [42] have explored the effect of relative phase between the probe and the driving fields on the gain and absorption in an open system with SGC. They have found EIT in the open system and have stated that EIT cannot occur in the closed system.…”

Section: Introductionmentioning

confidence: 99%

Combined effect of spontaneously generated coherence and dynamically induced coherence in a three-level closed Λ system

Dutta

Dastidar

2006

J. Phys. B: At. Mol. Opt. Phys.

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In a three-level closed Λ system with incoherent pumping, both the dynamically induced coherence (DIC) and the spontaneously generated coherence (SGC) play a significant role in inducing different nonlinear processes like amplification without population inversion (AWI), electromagnetically induced transparency (EIT) and electromagnetically induced absorption (EIA). These two coherences can interfere destructively and constructively giving rise to different nonlinear processes (EIT, EIA, AWI) when the strength of these two coherences is comparable. Therefore the system can switch over from one nonlinear process to the other and the desired response of the system can be achieved by controlling the system parameters. It has been shown that this switching can occur by changing the relative strength of Rabi frequencies for the coherent and probe fields and the mode of incoherent pumping (unidirectional and bidirectional) for a chosen SGC parameter. Further control over the response can be achieved by changing the phase between two radiation fields. But the dependence on phase is different when both the coherences contribute than that obtained only from SGC. Exact analytical expressions for the coherences and populations in the steady state limit have been derived (keeping all orders of system parameters) to generalize the analysis and any restrictions over the system parameters (e.g. spontaneous decay widths on probe and coherent transitions are equal) have been avoided to make it applicable to various atomic and molecular systems. However the approximate expressions can be derived from these exact values. Numerical values obtained by solving the density matrix equations agreed well with these exact analytical values.

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Section: Introductionmentioning

confidence: 99%

Combined effect of spontaneously generated coherence and dynamically induced coherence in a three-level closed Λ system

Dutta

Dastidar

2006

J. Phys. B: At. Mol. Opt. Phys.

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“…At present the effects of VIC on absorption, dispersion, populations, transition and other optical properties in an atomic system have been widely investigated [1][2][3][4][5][6][7][8][9][10] . The results show that the effect of VIC can not only change the characters of absorption and dispersion in an atomic system, but also lead to the characters of absorption and dispersion being sensitive to variation of the electric field phase particularly [11][12][13][14][15][16][17][18][19] . The research about the effects of VIC and the field phase mainly concentrated on the three-level atomic system.…”

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confidence: 96%

Phase-dependent gain without inversion in an inhomogeneous broadened quasi Λ-type four-level system with VIC

et al. 2010

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The effect of the relative phase ( φ ) between the probe and driving fields on the gain without inversion (GWI) is studied in a Doppler broadened quasi ∧-type four-level atomic system with vacuum induced coherence (VIC). It is shown that: The probe detuning region in which GWI exists and size of GWI are very sensitive to variation of the relative phase, the Doppler width ( D ) also has dramatically modulation role on the phase-dependent GWI. The GWI maximum value ( max G ) varies periodically with the relative phase varying, the period is 2π ; but the concrete varying rule is closely related to the value of the Doppler width. In the case of 0 D = (i.e. without Doppler broadening), when 0 φ π < < , max G increases monotonously with φ increasing; when 2 π φ π < < , max G decreases monotonously with φ increasing; when φ π = , max G has the largest value. Under the condition of 0 D ≠ (i.e. Doppler broadening presents), in both regions 0 φ π < < and 2 π φ π < < , max G does not monotonically increase or decrease with φ increasing; the value of φ , which corresponds to the largest value of max G , decreases gradually from π with D increasing, when value of D is large enough, the value of φ , which corresponds to the largest value of max G , is about / 2 π . In general speaking, max G decreases with D increasing; but max G larger than that in the corresponding static atomic system ( 0 D = ) can be gotten by choosing suitable values of φ and D .Keywords: quasi ∧-type four-level system; relative phase; Doppler broadening; vacuum induced coherence; lasing without inversion; gain INTRODUCTIONIn the past few decades LWI has attracted much more attention and has been extensively studied. This may be very useful for getting laser actions in some special spectral regions (e. g., the UV and X-ray regions), because in these regions it is very difficult to get the population inversion by means of the conventional pumping method. Moreover, LWI has some interesting statistical properties, such as narrower intrinsic line-width and amplitude-squeezing, which could be advantageous in, for example, optical communication networks. LWI originates from the atomic coherence and quantum interference effects. Generally, it is produced by a coherent driving field or by initial coherence. A kind of coherence can be created by interference of spontaneous emission, usually called vacuum induced coherence (VIC) (also called as spontaneously generated coherence (SGC)). At present the effects of VIC on absorption, dispersion, populations, transition and other optical properties in an atomic system have been widely investigated [1][2][3][4][5][6][7][8][9][10] . The results show that the effect of VIC can not only change the characters of absorption and dispersion in an atomic system, but also lead to the characters of absorption and dispersion being sensitive to variation of the electric field phase particularly [11][12][13][14][15][16][17][18][19] . The research about the effects of VIC and the field phase mainly concentrated on the three-level atom...

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“…In this case, we have to treat the Rabi frequencies as complex parameters [29]. We define ϕ p , ϕ c , and ϕ d as the phases of the probe, control, and microwave fields, respectively.…”

Section: Model and Motion Equationsmentioning

confidence: 99%

Coherent control of optical bistability in an open Λ-type three-level atomic system

et al. 2012

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We analyze the hybrid absorptive-dispersive optical bistability (OB) behavior in an open Λ-type three-level atomic system by using a microwave field to drive the hyperfine transition between two lower states, along with the consideration of incoherent pumping and spontaneously generated coherence. Different from the closed system, we show that the bistable threshold intensity and related hysteresis loop can be controlled by adjusting the ratio between atomic injection and exit rates. More interestingly, the appearance and disappearance of OB can be transformed mutually by varying the relative phase of three coherent fields under the condition of a strong spontaneously generated coherence. The manipulation of OB behavior through the intensity of the microwave field and the atomic cooperation parameter is also analyzed.

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Phase control of gain and dispersion in an open lambda-type inversionless lasing system

Cited by 18 publications

References 50 publications

Combined effect of spontaneously generated coherence and dynamically induced coherence in a three-level closed Λ system

Combined effect of spontaneously generated coherence and dynamically induced coherence in a three-level closed Λ system

Phase-dependent gain without inversion in an inhomogeneous broadened quasi Λ-type four-level system with VIC

Coherent control of optical bistability in an open Λ-type three-level atomic system

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