一个四能级相干驱动原子系统中的多透明窗

研究了在两个相干场驱动下呈现多透明窗特征的四能级原子系统. 该系统是N型四能级模型, 当只存在一个相干场时, 是典型的三能级V模型透明结构, 而在两个相干场的驱动下, 该系统呈现出两个透明窗口, 透明窗的位置、 宽度和吸收高度均可以通过调节驱动场的强度和失谐进行控制. 每个透明窗口在吸收最低时都伴随着高折射, 表明探测光的群速度在每个透明窗口都变慢了.

Electromagnetically Induced Transparency Window in the System of Four-level Configuration

The absorption and dispersion properties of an N-type four-level system with Doppler(broadening) effect were investigated.In this system we considered two coherent fields and a probe field.When the second coherent field is absent,this system is a single three-level configuration,and the absorption line is just one clear electromagnetically induced transparency(EIT) window.While the second coherent field exists,there are two EIT windows which become wide and deep with the(coherent) intensity increasing.The position width and absorbance of the transparency windows can be manipulated by adjusting the detuning of the driving field.In addition,we also found that the medium shows a large refractive index at each transparency window,and the group velocity of the probe laser can be reduced.