Comparison between effects of Doppler broadening on pure and non-pure inversionless gains with frequency up-conversion
Fan Xi-Jun(樊锡君)a)†, Ma Hui(马慧)b), Liu Zhong-Bo(刘中波)a), and Tong Dian-Min(仝殿民)c)
a College of Physics and Electronics, Shandong Normal University, Jinan 250014, China; b School of Mathematics and Physics, Shandong Institute of Light Industry, Jinan 250353, China; c School of Physics and Microelectronics, Shandong University, Jinan 250100, China
Abstract A study is made of the effects of Doppler broadening on pure gain without inversion, which means that neither one-photon nor two-photon inversions are allowed, and non-pure gain without inversion, which means that one-photon inversion does not occur but two-photon inversion is present, in a closed $\Lambda$-type three-level system with incoherent pumping. It is shown that when the driving field is resonant but the probe field is not, in a certain range of Doppler width, for the case of the lower degree of frequency up-conversion, generally, pure gain without inversion increases monotonically and non-pure gain without inversion does not monotonically increase or decrease with increasing Doppler width; for the case of the higher degree of frequency up-conversion, pure gain without inversion decreases monotonically but non-pure gain without inversion cannot be produced. In the case of two-photon resonance, in some range of Doppler width, pure gain without inversion does not monotonically increase or decrease while non-pure gain without inversion decreases monotonically with Doppler width increasing. Finally, an experimental scheme for examining our theoretical result is given.
Received: 08 March 2009
Revised: 06 May 2009
Accepted manuscript online:
PACS:
42.50.Gy
(Effects of atomic coherence on propagation, absorption, and Amplification of light; electromagnetically induced transparency and Absorption)
(Mechanical effects of light on atoms, molecules, and ions)
Fund: Project supported by the Natural
Science Foundation of Shandong Province, China (Grant No Y2006A21)
and the National Natural Science Foundation of China (Grant No
10675076).
Cite this article:
Fan Xi-Jun(樊锡君), Ma Hui(马慧), Liu Zhong-Bo(刘中波), and Tong Dian-Min(仝殿民) Comparison between effects of Doppler broadening on pure and non-pure inversionless gains with frequency up-conversion 2009 Chin. Phys. B 18 5342
Altmetric calculates a score based on the online attention an article receives. Each coloured thread in the circle represents a different type of online attention. The number in the centre is the Altmetric score. Social media and mainstream news media are the main sources that calculate the score. Reference managers such as Mendeley are also tracked but do not contribute to the score. Older articles often score higher because they have had more time to get noticed. To account for this, Altmetric has included the context data for other articles of a similar age.
