Eur. Phys. J. D 57, 241-246 (2010)
https://doi.org/10.1140/epjd/e2010-00020-1

Controlling the optical bistability via interacting dark-state resonances

¹ Physics Department, Zanjan University, P.O. Box 45195, -313, Znjan, Iran
² Research Institute for Applied Physics and Astronomy, University of Tabriz, Tabriz, Iran

Corresponding author: mahmoudi@znu.ac.ir

Received: 15 August 2009
Revised: 16 December 2009
Published online: 26 January 2010

Abstract

We analyze the behavior of optical bistability in a four-level mercury atomic system driven by a cavity and two external coherent fields by means of a unidirectional ring cavity. We find that without interacting dark resonances and for large intensity of coupling field, the optical bistability disappears. So, the double dark resonances could significantly establish the optical bistability. Moreover, we demonstrate that the double dark resonances can dramatically reduce the threshold of optical bistability.