An optical lens including a first light exit surface, a total internal reflection surface, a second light exit surface and a third light exit surface connected in an order, and correspondingly has a first intersection, a second intersection and a third intersection therebetween. An electron beam tunnel passes through the coupled cavity circuit to allow a beam of electrons to pass through and interact with the electromagnetic energy in the cavities. The system is particularly advantageous in scenarios where a session’s connection is lost and the session has to be reconnected to the network.