Feature

RF Coupled Optical Gain in a Solid Owing to Quantum Interference

Byoung S. Ham and Selim M. Shahriar, Research Lab. of. Electronics, MIT, Cambridge, MA; Philip R. Hemmer, Air Force Research Laboratory, Hanscom AFB, MA.

The interaction of a strong resonant laser field with two levels in a three-level system can modify the absorption and refractive index of a probe field whose transition involves the third level. Particularly, the probe field is not absorbed at line center due to two-photon coherence and destructive quantum interference, so that an optically thick medium can become transparent. This is called electromagnetically induced transparency (EIT).