APPLICATION OF ELECTROMAGNETICALLY INDUCED TRANSPARENCY (EIT) IN QUANTUM COMMUNICATION: A REVIEW

Abstract

Electromagnetically induced transparency is a promising approach to implement quantum
communication in quantum system. In this study, quantum coherence and interference in the
excitation pathways of a three-level Λ atomic system leads to the formation of new states of matter
(i.e. the dark state). This state decouples itself from the excitation beams leading to phenomena
such as coherent population trapping (CPT), electromagnetically induced transparency (EIT).
Taking into account quantum coherence and interference in an optically dense electromagneticallyinduced
transparent medium, we investigate the non-destructive storage and retrieval of singlephoton
quantum states in the dark state of this dense ensemble of gas phase medium. The storage
and retrieval process is based on the intracavity electromagnetically induced transparency by which
properties of a cavity filled with three-level Λ-type atoms are manipulated by an external control field.
We demonstrate the peculiar case for the storage and retrieval of time-entangled periodic input pulses
(a soliton train) in the dark state by adiabatic photon transfer under conditions of dynamical
impedance matching. These multiplexed photon states are expected to allow sharing quantum
information among many users, and are currently of very high demand for applications in longdistance
and multiplexed quantum communication.