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Journal of Optoelectronics·laser

SGC effect in an open quasi-Λ type four-level system with Doppler broadening

Fan Xijun

Published Jan 1, 2008• 0 citations
OpenAlex

Abstract

The effect of spontaneously generated coherence on the gain of lasing without inversion(LWI) is studied in an open quasi-Λ type four-level atomic system with Doppler broadening from different respects.The results show that,for a fixed SGC strength,LWI gain decreases with increasing the value of the Doppler width;no matter the Doppler broadening is obvious or not,the LWI gain larger than that without SGC always can be gotten by choosing suitable value of the SGC strength,and this difference becomes more evident with the Doppler width decreasing;the atomic exit and injection rates also can dramatically affect LWI gain;a much larger LWI gain in open system than that in the corresponding closed system can be obained.

Related papers

Effect of spontaneously generated coherence on inversionless lasing gain in an atomic system with Doppler broadening

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We have studied the effect of the spontaneously generated coherence (SGC) on gain of lasing without inversion (LWI) in a closed three-level Λ-type atomic system with Doppler broadening. It is shown that, regardless of the driving and probe fields being co- or counter-propagating, at a suitable value of the Doppler width, we can obtain a much larger LWI gain with SGC than that without SGC; and the region of the LWI gain spectrum with SGC is obviously larger than that without SGC. When the Doppler width takes a constant value, the gain does not monotonically decrease or increase with increasing strength of SGC, the largest LWI gain can be obtained by adjusting strength of SGC. Generally speaking, the co-propagating probe and driving fields is favourable to obtain a larger LWI gain.

Chinese Physics•Aug 1, 2007•4 citations

Spontaneously Generated Coherence in an Open Four-level Atomic System

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We put forward a model of an open quasi Λ-type four-level atomic system,and then investigate the effect of spontaneously generated coherence(SGC) on the gain of lasing without inversion from different respects by using the numerical calculation results of the system in the steady state.The study results show that,the switching from absorption to lasing without inversion(LWI) and the enhancement of the LWI gain can be realized by adjusting the strength of SGC;the variety of the two factors p1 to p2 which represent the SGC effect will produce remarkable different influence on the LWI gain.We also find that,the LWI gain is much larger in open system than that in the corresponding closed system;moreover,when the incoherent pump field is absent,the LWI gain can be obtained in the open system but cant in the closed system.

Journal of Optoelectronics·laser•Jan 1, 2007•0 citations

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Chinese Physics B•Feb 1, 2012•5 citations

Influence of Doppler broadening and spontaneously generated coherence on propagation effect in a quasi lambda-type four-level system

刘中波, 梁颖, 贾克宁 +1 more

In this paper we study influences of Doppler broadening,spontaneously generated coherence,and other system parameters on propagation effect in a quasi lambda-type four-level atomic system.It is shown that when the Doppler broadening is present,generally speaking,the values of gain and intensity of lasing without inversion (i.e.the probe field) in the co-propagating probe and driving fields case are much larger than those in the counter-propagating case;considerably larger gain and intensity of lasing without inversion than those without the Doppler broadening can be obtained by choosing appropriate values of the Doppler broadening width and spontaneously generated coherence strength.The gain and intensity of lasing without inversion increase with the increase of spontaneously generated coherence strength;when spontaneously generated coherence is present,much larger gain and intensity of lasing without inversion than those in the case without spontaneously generated coherence can be obtained.Choosing suitable values of the probe detuning,Rabi frequencies of the driving and pump fields at the entrance of the medium also can remarkably enhance the gain and intensity of lasing without inversion.更多还原

Chinese Physics B•Jan 1, 2012•0 citations

Modulation of atomic exit and injection rates on the phase-dependent gain without inversion in a Doppler broadened open four-level system

Zhongbo Liu, Kening Jia, Ying Liang +2 more

It is shown that in a Doppler broadened open N-type four-level atomic system with spontaneously generated coherence (SGC), the gain without inversion (GWI) is very sensitive to the variation of the relative phase between the probe field and the driving field; the atomic exit rate ( R 0 ) and the ratio ( S ) of the atomic injection rates have a considerable modulation effect on the phase-dependent GWI. GWI first increases and then decreases with Ro increasing; in a certain value range of S , GWI increases monotonically with S increasing; by adjusting the values of R 0 and S , in an open system a much larger GWI can be obtained than in the corresponding closed system [ 2011 Phys. Rev. A 83 043805 ]. The modulation effects of R 0 and S on the phase-dependent GWI in the case with the counter-propagating probe and driving fields are stronger than those in the co-propagating case, GWI in the co-propagating case is much larger than that in the counter-propagating case.

Chinese Physics B•Jun 1, 2012•2 citations
The effect of spontaneously generated coherence on the gain of lasing without inversion(LWI) is studied in an open quasi-Λ type four-level atomic system with Doppler broadening from different respects.The results show that,for a fixed SGC strength,LWI gain decreases with increasing the value of the Doppler width;no matter the Doppler broadening is obvious or not,the LWI gain larger than that without SGC always can be gotten by choosing suitable value of the SGC strength,and this difference becomes more evident with the Doppler width decreasing;the atomic exit and injection rates also can dramatically affect LWI gain;a much larger LWI gain in open system than that in the corresponding closed system can be obained.
We have studied the effect of the spontaneously generated coherence (SGC) on gain of lasing without inversion (LWI) in a closed three-level Λ-type atomic system with Doppler broadening. It is shown that, regardless of the driving and probe fields being co- or counter-propagating, at a suitable value of the Doppler width, we can obtain a much larger LWI gain with SGC than that without SGC; and the region of the LWI gain spectrum with SGC is obviously larger than that without SGC. When the Doppler width takes a constant value, the gain does not monotonically decrease or increase with increasing strength of SGC, the largest LWI gain can be obtained by adjusting strength of SGC. Generally speaking, the co-propagating probe and driving fields is favourable to obtain a larger LWI gain.
We put forward a model of an open quasi Λ-type four-level atomic system,and then investigate the effect of spontaneously generated coherence(SGC) on the gain of lasing without inversion from different respects by using the numerical calculation results of the system in the steady state.The study results show that,the switching from absorption to lasing without inversion(LWI) and the enhancement of the LWI gain can be realized by adjusting the strength of SGC;the variety of the two factors p1 to p2 which represent the SGC effect will produce remarkable different influence on the LWI gain.We also find that,the LWI gain is much larger in open system than that in the corresponding closed system;moreover,when the incoherent pump field is absent,the LWI gain can be obtained in the open system but cant in the closed system.
In this paper we study the influence of spontaneously generated coherence (SGC) on propagation effect and the modulation role of the atomic exit rate(r0)and ratio(S) of the atomic injection rates on the SGC-dependent propagation effect in an open V-type three-level lasing without inversion(LWI) system with Doppler broadening,by using the calculation results of the density matrix motion equations and the propagation equations of the driving and probe fields,in order to get larger LWI gain and intensity of the probe field.It is shown that with propagation distance increasing,LWI gain and Rabi frequency(intensity) of the probe field first increase and then decrease,while the Rabi frequency(intensity) of the driving field decreases monotonously;LWI gain and Rabi frequency(intensity) of the probe field increase with SGC strength(measured by θ) increasing.When θ=π,we can obtain the largest LWI gain and Rabi frequency(intensity) of the probe field;in the case with SGC,we can get much larger LWI gain and Rabi frequency(intensity) of the probe field than those in the case without SGC.In certain value ranges of r0 and S,LWI gain and Rabi frequency(intensity) of the probe field increase with r0 and S increasing.By choosing proper values of γ0 and S,in the open system we can obtain much higher LWI gain and Rabi frequency(intensity) of the probe field than those in the corresponding closed system.
In this paper we study influences of Doppler broadening, spontaneously generated coherence, and other system parameters on propagation effect in a quasi lambda-type four-level atomic system. It is shown that when the Doppler broadening is present, generally speaking, the values of gain and intensity of lasing without inversion (i.e. the probe field) in the co-propagating probe and driving fields case are much larger than those in the counter-propagating case; considerably larger gain and intensity of lasing without inversion than those without the Doppler broadening can be obtained by choosing appropriate values of the Doppler broadening width and spontaneously generated coherence strength. The gain and intensity of lasing without inversion increase with the increase of spontaneously generated coherence strength; when spontaneously generated coherence is present, much larger gain and intensity of lasing without inversion than those in the case without spontaneously generated coherence can be obtained. Choosing suitable values of the probe detuning, Rabi frequencies of the driving and pump fields at the entrance of the medium also can remarkably enhance the gain and intensity of lasing without inversion.
In this paper we study influences of Doppler broadening,spontaneously generated coherence,and other system parameters on propagation effect in a quasi lambda-type four-level atomic system.It is shown that when the Doppler broadening is present,generally speaking,the values of gain and intensity of lasing without inversion (i.e.the probe field) in the co-propagating probe and driving fields case are much larger than those in the counter-propagating case;considerably larger gain and intensity of lasing without inversion than those without the Doppler broadening can be obtained by choosing appropriate values of the Doppler broadening width and spontaneously generated coherence strength.The gain and intensity of lasing without inversion increase with the increase of spontaneously generated coherence strength;when spontaneously generated coherence is present,much larger gain and intensity of lasing without inversion than those in the case without spontaneously generated coherence can be obtained.Choosing suitable values of the probe detuning,Rabi frequencies of the driving and pump fields at the entrance of the medium also can remarkably enhance the gain and intensity of lasing without inversion.更多还原
It is shown that in a Doppler broadened open N-type four-level atomic system with spontaneously generated coherence (SGC), the gain without inversion (GWI) is very sensitive to the variation of the relative phase between the probe field and the driving field; the atomic exit rate ( R 0 ) and the ratio ( S ) of the atomic injection rates have a considerable modulation effect on the phase-dependent GWI. GWI first increases and then decreases with Ro increasing; in a certain value range of S , GWI increases monotonically with S increasing; by adjusting the values of R 0 and S , in an open system a much larger GWI can be obtained than in the corresponding closed system [ 2011 Phys. Rev. A 83 043805 ]. The modulation effects of R 0 and S on the phase-dependent GWI in the case with the counter-propagating probe and driving fields are stronger than those in the co-propagating case, GWI in the co-propagating case is much larger than that in the counter-propagating case.