The State‘s Attorney or an Assistant State’s Attorney authorized by the State’s Attorney may authorize an application to a circuit judge or an associate judge assigned by the Chief Judge of the circuit for, and such judge may grant in conformity with this Article, an order authorizing or approving the use of an eavesdropping device by a law enforcement officer or agency having the responsibility for the investigation of any felony under Illinois law where any one party to a conversation to be monitored, or previously monitored in the case of an emergency situation as defined in this Article, has consented to such monitoring.
     The Chief Judge of the circuit may assign to associate judges the power to issue orders authorizing or approving the use of eavesdropping devices by law enforcement officers or agencies in accordance with this Article. After assignment by the Chief Judge, an associate judge shall have plenary authority to issue such orders without additional authorization for each specific application made to him by the State’s Attorney until such time as the associate judge’s power is rescinded by the Chief Judge.