Rigorous Model of Nonlinear Optomechanical Coupling in Micro- and Nano-Structured Resonant Cavities
We introduce an accurate analytical and numerical method aimed to predict the optomechanical dynamics in micro- and nano-structured resonant cavities by exploiting the harmonic version of the Transformation Optics (TO) technique. In respect to the standard optomechanical perturbative theory, our full-wave approach implements a multimodal analysis and also considers material losses, from both a mechanical and an optical point of view. The rigorousness of the theoretical aspect of the model is ensured by considering all the energy-transduction contributions of electrostriction, radiation pressure, photoelasticity and moving boundaries. The efficiency of the strategy is tested by analyzing the optomechanical behavior of a corrugated Si-based nanobeam and comparing numerical results to experimental ones from the literature, showing a good agreement, thus confirming versatility and efficiency.