Characterization of optomechanical cavities

Abstract

The coupling between optical and mechanical waves has been a growing study field for the last few years. Optomechanical crystals (OMCs), also known as Phoxonic crystals, are periodical nanostructures that can present bandgaps for both photons and phonons. By injecting a slight defect into the OMCs one can place particular modes inside the gaps enabling light and motion to effectively localize in the same volume, thus enhancing the optomechanical interaction. The latter allows the optical transduction of nanomechanical motion with near quantum-limited sensitivity, which drives us to applications such as signal processing and high-speed sensing systems. This study aims to experimentally characterize a set of optomechanical devices and point out their effectiveness in terms of their optical and mechanical quality factor (Q factor). In this regard, I have found that the best Q factor values appear as a compromise between the geometrical depth of the defect and the fabrication limitations, and I also noticed a significant difference between mechanical and optical losses due to their main dissipating mechanisms, leading to lower mechanical Q factors