Integrated mechano-optical hydrogen gas sensor using cantilever bending readout with a Si₃N₄ grated waveguide.

We demonstrate a proof of concept of a novel and compact integrated mechano-optical sensor for H2 detection based on a microcantilever suspended above a Si3N4 grated waveguide. The fabricated devices are mechanically and optically modeled and characterized. Sensing operation of the sensor is demonstrated with 1% H2 in N2. The error in detection of the cantilever bending induced by absorption of H2 is estimated to be approximately 10 nm. Significantly improved sensitivity (down to ∼33 pm) is expected for reduced initial bending of the microcantilever. The simulation and experimental results are in good agreement and provide a good guideline for further optimization of the sensor.