Read-Out of Cantilever Bending With a Grated Waveguide Optical Cavity

We present results related to the fabrication of a novel and potentially highly sensitive mechano-optical sensor for hydrogen gas, based on microcantilevers, provided with a selectively gas-absorbing palladium layer, suspended above a Si
₃
N
₄
grated waveguide (GWG). Integrated microcantilever-GWG devices have been fabricated successfully using microelectromechanical systems (MEMS) techniques. Several technical problems encountered during the preparation of such integrated devices (i.e., grating production, surface roughness, facet quality) will be discussed, and solutions to address these issues will be given as well. We also present preliminary experimental results, showing the sensing of cantilever nano-displacements, and so the feasibility of proposed read-out principle.