Aspects of EIT with gamma radiation.

We have observed the effect of electromagnetically induced transparency (EIT) in a nuclear system. A series of Mössbauer measurements was performed on a single crystal of natural FeCO₃. When the condition of nuclear level crossing is fulfilled, a clear reduction in absorption or transparency is seen at the point of level crossing. This reduced absorption cannot be ascribed to saturation effects because of the specific geometry of the experiment. We present an explanation in terms of level mixing by a small non-axial component of the electric field gradient. It can be shown that such a scheme is equivalent, at least in principle, with the schemes considered for EIT in quantum optics. [ABSTRACT FROM AUTHOR]