Journal of Modern Optics
Manipulating the focal shift in a medium with electromagnetically induced transparency
Chunfang Wang, Jing Cheng, Shensheng Han
Abstract
By approximating the index distribution of a medium with electromagnetically induced transparency (EIT) as a gradient index (GRIN), propagation laws in the medium with EIT can be obtained. Transmission properties in an optical system with an EIT medium are analyzed. The results show that, unlike the case in the ordinary GRIN medium, the refractive index of EIT medium has the better controllability. Consequently, discussions are focused on how to conveniently manipulate the focal shift of the input in the EIT by means of controlling the index of the medium. Additionally, the speckle radius on the location of the actual focus can be diminished by adjusting some parameters in the EIT medium.