Abstract We have studied theoretically constructive interference via collision-aided radiative excitation in an open four-level system using a density matrix approach. The four-level system consists of a $\varLambda$-type three-level quantum-beat configuration driven by one laser field and a fourth level coupled by a vacuum mode. It is shown that through the incoherent process (collision), coherence between widely-separated doublets and subsequent constructive interference can be realized. We analyse the effects of the collision-induced coherent and incoherent decay rates, laser intensity, and energy separation of the doublets on the interference. Meanwhile, the constructive interference between the two transition pathways 3P1/2-4D and 3P3/2-4D via equal-frequency hybrid excitation and collision-aided radiative excitation in an Na2-Na system is experimentally observed. A good agreement between the theoretical and experimental results is obtained.
Received: 20 May 2001
Revised: 08 December 2001
Accepted manuscript online:
PACS:
42.50.Md
(Optical transient phenomena: quantum beats, photon echo, free-induction decay, dephasings and revivals, optical nutation, and self-induced transparency)
Fund: Project supported by the National Natural Science Foundation of China (Grant Nos 19734003 and 10074015).
Cite this article:
Yang Xi-Hua (杨希华), Sun Zhen-Rong (孙真荣), Ding Liang-En (丁良恩), Wang Zu-Geng (王祖赓) Constructive interference via collision-aided radiative excitation 2002 Chinese Physics 11 346
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