Cavity optomechanics, which combines a mechanical degree of freedom to an optical cavity via resonantly enhanced feedback backaction mechanism, has attracted great interest and seen remarkable progress in many fields of physics, including precision force sensing and manipulation of mechanical motion at the quantum limit.  Recently, effects arise from the nonlinear optomechanical interaction emerging as a new frontier in cavity optomechanics due to breakthroughs of intrinsic characteristics of the linearized optomechanical interaction, and have enabled some interesting topics in both classical (or semiclassical) and quantum mechanism, such as second and higher-order sideband generation, frequency comb, and optomechanical chaos.

Prof. Ying Wu’s group from Wuhan National Lab for Optoelectronics (WNLO) and school of physics proposed to show sum sideband generation in a generic optomechanical system in the parameter configuration of optomechanically induced transparency. The nonlinear terms of the optomechanical dynamics are taken account and the features of the sum sideband generation are identified based on the analytical treatment. The nonlinear optomechanical interactions between cavity fields and the mechanical oscillation are responsible for the generation of the frequency components at the sum sideband. The influences of some parameters, including the pump power of the control field and the frequencies of the probe fields, on the sum sideband generation are discussed. The results clearly indicate that sum sideband generation can be significantly enhanced via achieving the matching conditions.

This work, published in Optics Express (Vol.24, no.6, PP.5773-5783, 2016), was supported in part by the National Natural Science Foundation of China (Grant Nos. 11405061,11574104).

Fig. 1. (a) Schematic diagram of a double probe fields driven optomechanical system. (b) Frequency spectrogram of sum sideband generation in the optomechanical system.

Fig. 2. Efficiencies (in logarithmic form) of (a) upper and (b) lower sum-sideband generation indicate the matching conditions.