Optically Driven Nano-Beam Resonator for Hydrogen Sensing

We introduce a hydrogen sensor based on a beam-structured optomechanical resonator engraved by the FIB (focused ion beam) in a graphene-Au-Pd nanofilm, suspending on the tip of the optical fiber. The hydrogen concentration can be measured by monitoring the resonance frequency change which attribute to the mechanical stress changes associated with hydrogen. The sensor responds linearly in a wide concentration range of from 0 to 4.5%. The sensitivity of proposed sensor can be calculated to be 95.7 kHz/% with a shift of 445.11 kHz. Due to its excellent repeatability in the measurement process, such a sensor may be used practically for hydrogen gas with high concentrations.