Direct Determination of Optomechanical Photonic Crystal Mechanical Mode Profile via Quasi Near-Field Perturbation

Purely optical photonic crystals have been intensively studied with SNOM (Scanning Near-field Optical Microscopy) techniques [1], [2] giving important information about losses channels and confinement of photons at the nanoscale. Recently, photonic crystals have been considered for their optomechanical properties, which would be of great interest e.g. for new GHz integrated oscillators [3] or quantum applications [4]. In these crystals, experimental observations match results from numerical simulations of mechanical modes. However, the spatial distribution of phonons is deduced from the simulations without any experimental demonstration, yet. The in situ investigation of the mechanical losses and mode extension would provide interesting hints on the design optimization of optomechanical crystals, which would allow to improve the performance of these new devices.