探测功率展宽效应引起的电磁诱导透明向电磁诱导吸收的转化

Transformation from electromagnetically induced transparency to electromagnetically induced absorption due to the power broadening of probing field

本文对准L型四能级系统中探测功率展宽效应引起的非线性效应进行了理论研究.准L型四能级系统包括三个基态精细结构能级和一个激发态能级,除光学耦合场和探测场分别激励一个基态精细结构能级和激发态能级之间的跃迁外,附加了一个射频驱动场作用于其中一个基态精细结构能级和另一个新的基态精细结构能级之间,并通过与耦合场驱动共同能级建立量子相关性.研究结果表明,在射频驱动场的辅助激励下,探测功率展宽效应不仅可以使EIT的线宽增宽,还能引起吸收曲线中的类色散特性,使EIT最终变化为EIA.

In this paper we present a theoretical study of the nonlinear effect induced by the power broadening of probing field in the quasi-lambda type four-level system. The system consists of an excited state level and three ground state hyperfine levels. Probing and coupling field are coupled to between the excited state and two higher ground states, and the radio field drives the two lower ground states which are associated with coupling field. It can be seen that under the help of radio field interacting with the hyperfine transition, the power broadening of probing field not only may cause the line width broadening of EIT, but can also cause the dispersion characteristic in the absorption profiles and cause the transformation from EIT to EIA.