Normal-Mode Splitting in a Weakly Coupled Electromechanical System with a Mechanical Modulation

摘要

Normal-mode splitting (NMS) is one of the most significant manifestations of strongly coupled systems. Here, NMS is shown to occur in a weakly coupled electromechanical system. In this system, an exponentially enhanced electromechanical coupling is obtained by periodically modulating the electromechanical interaction and the mechanical spring constant. Under the mechanical modulation, an obvious NMS can occur in the fluctuation spectra of the mechanical oscillator's displacement and the output field. Besides, the Stokes and anti-Stokes fields can also display an obvious NMS. Interestingly, the Stokes field can be changed from full absorption to significant amplification, and the anti-Stokes field can also be enhanced significantly. Another novel feature of the results is that the intensity between the two peaks in NMS is almost zero, which means that the two peaks can be well resolved in experiments. This work presents an effective method for the generation of a well-resolved NMS in a weakly coupled system.