中国物理B ›› 2007, Vol. 16 ›› Issue (10): 2973-2979.doi: 10.1088/1009-1963/16/10/026

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Inversionless gain enhancing due to Doppler broadening in a closed lambda-type system

马 慧1, 谭 霞1, 仝殿民1, 樊锡君1, 田淑芬2   

  1. (1)College of Physics and Electronics, Shandong Normal University, Jinan 250014, China; (2)Communication College, Shandong Normal University, Jinan 250014, China
  • 收稿日期:2006-12-24 修回日期:2007-04-17 出版日期:2007-10-08 发布日期:2007-10-08
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No 10675076), the Natural Science Foundation of Shandong Province of China (Grant No Y2006A21) and the State Key Laboratory of High Field Laser Physics, Shanghai Institute of Opt

Inversionless gain enhancing due to Doppler broadening in a closed lambda-type system

Ma Hui(马慧)a), Tian Shu-Fen(田淑芬)b), Tan Xia(谭霞)a), Tong Dian-Min(仝殿民)a), and Fan Xi-Jun(樊锡君)a)†   

  1. a College of Physics and Electronics, Shandong Normal University, Jinan 250014, China; b Communication College, Shandong Normal University, Jinan 250014, China
  • Received:2006-12-24 Revised:2007-04-17 Online:2007-10-08 Published:2007-10-08
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No 10675076), the Natural Science Foundation of Shandong Province of China (Grant No Y2006A21) and the State Key Laboratory of High Field Laser Physics, Shanghai Institute of Opt

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摘要： An analysis is made of the effect of Doppler broadening on gain without inversion (GWI) from different aspects in a closed lambda-type three-level system with an incoherent pump. It is shown that, regardless of the driving field being on resonance or not, for the counter- or co-propagating of the probe and driving fields (PDF), GWI does not monotonically decrease or increase with increasing Doppler width. Except for the case of counter-propagating PDF with off-resonance driving field, at a suitable Doppler width one can obtain a gain maximum value much larger than that without Doppler broadening; especially in the situation of the resonant driving field, the co-propagating geometry leads to a larger GWI. In addition, for the counter-propagating geometry, when Doppler width is larger enough, GWI oscillation occurs, and the oscillation amplitude and region increase with increasing Doppler width. These conclusions are very different from that obtained in previous investigation (Lukin {\it et al}, {\it Laser Phys.} {\bf 6} 436 (1996)).

关键词: closed system, Doppler broadening, gain without inversion

Abstract: An analysis is made of the effect of Doppler broadening on gain without inversion (GWI) from different aspects in a closed lambda-type three-level system with an incoherent pump. It is shown that, regardless of the driving field being on resonance or not, for the counter- or co-propagating of the probe and driving fields (PDF), GWI does not monotonically decrease or increase with increasing Doppler width. Except for the case of counter-propagating PDF with off-resonance driving field, at a suitable Doppler width one can obtain a gain maximum value much larger than that without Doppler broadening; especially in the situation of the resonant driving field, the co-propagating geometry leads to a larger GWI. In addition, for the counter-propagating geometry, when Doppler width is larger enough, GWI oscillation occurs, and the oscillation amplitude and region increase with increasing Doppler width. These conclusions are very different from that obtained in previous investigation (Lukin et al, Laser Phys. 6 436 (1996)).

Key words: closed system, Doppler broadening, gain without inversion

中图分类号:  (Line shapes, widths, and shifts)

  • 32.70.Jz
42.50.Gy (Effects of atomic coherence on propagation, absorption, and Amplification of light; electromagnetically induced transparency and Absorption)