理论研究了五能级系统中三光子共振非简并六波混频(NSWM)由于中间能级加入耦合光场而产生的量子干涉效应.分析了耦合光场对三光子共振NSWM信号以及频谱的影响.研究发现,在强耦合场作用下,NSWM的频谱出现了Autler-Townes分裂,它反映的是两个缀饰态的能级,量子干涉可以使NSWM信号被抑制或增强.提出利用量子干涉对NSWM信号产生增强作用,可以由耦合场产生的缀饰态代替原子固有能级,成为三光子共振的中间态,从而控制耦合场来选择三光子共振的中间态的位置.
We study the quantum interference in three-photon resonant nondegenerate six-wave mixing(NSWM) of a five-level system in which the middle level of six-wave mixing and other levels are coupled by a strong laser field.The coupling field-dependence of the NSWM signal intensity,and the spectrum of the NSWM with a coupling field,are discussed.We find that in the presence of a strong coupling field,the three-photon resonant NSWM spectrum exhibits Autler-Townes splitting,which reflects the levels of the dressed states.It also leads to either suppression or enhancement of the NSWM signal.Due to the enhancement of NSWM signal caused by quantum interference,the dressed state created by a coupling field can replace the atom intrinsic level and serve as the middle level of three-photon resonance.Thus the middle level of three-photon resonance can be controlled by a coupling field.