Interaction-free All-optical Switching Based On The Cavity-atom System

In contemporary society,the optical communication technology is playing an increasingly important role in people's life,therefore,it is very important to develop the optical communication technology and improve the efficiency and speed of the all optical network.Then,the progress of the corresponding devices and subsystems are promoted as the development of optical communication.All optical operations are the overall trend of the development of optical communication.The all-optical switching,which is the core of the all optical operation devices,has attracted a lot of attention in recent years.The realization of all-optical switching mainly based on the coupling between the control light and the signal light.However,as we all know,the coupling between the control light and the signal light would cause the loss of the photon number in the medium,so the efficiency of the optical switching was limited.Therefore,it is very important to avoid the coupling between the control light and the signal light,and realize the interaction-free all-optical switching.In this paper,we present the schemes of the interaction-free all-optical switching based on the cavity-atom system utilizing the quantum interference effect.The main results and innovation points are shown as the following:1.A scheme is proposed for interaction-free all-optical switching based on the system of double-cavities coupled by three-level atoms.In the scheme,the output signal light of the reflection and the transmission channels can be switched on or off by manipulating the control field on or off.When the control light is coupled to the atoms,the input signal light is reflected by the first cavity and such that there is no direct coupling of the control light and the signal light in the atom-cavity system.Furthermore,the all-optical switching is realized under the weak coupling between the atoms and the cavity.2.A scheme is proposed for tunable all-optical switching based on the double-dark states in a five-level atom-cavity system.In the scheme,the output signal light of the reflection and the transmission channels can be switched on or off by manipulating the control field on or off,which is similar to the previous scheme mentioned above.However,in this scheme,the switching is realized based on the double-dark states,which don't contain the excited states and nearly unaffected by the spontaneous emission,thus the efficiency is greatly improved.Furthermore,the position of the double-dark states can be changed by adjusting the coherent interaction,and thus the switching in our scheme is tunable.