Spacing-Dependent Electromagnetically Induced Transparency with two nuclear ensembles inside an x-ray planar cavity

The x-ray planar cavity embedded in two nuclear ensembles at node and antinode positions with fixed spacing has been used to study the electromagnetically induced transparency (EIT)-like effect previously. In this work, the same x-ray planar cavity but with a flexible spacing configuration is studied theoretically. By developing a concise transfer matrix method, the changing of spacing is reflected conveniently as the phase shift of the propagation matrices, based on which the system can be solved analytically. A periodic characteristic as a function of the spacing is observed, i.e., the first nuclear ensemble locating at any node will result in an EIT effect while the EIT effect will be completely compressed when it is at any antinode. It indicates that the phase shift between the two nuclear ensembles plays a key role for the coupling field. This kind of phase manipulation will enrich the approaches of quantum control in the x-ray regime.