Hyperbolic metamaterials assisted ultrathin Pd films for high-sensitivity hydrogen sensors

Abstract Optical hydrogen sensors can use optical fiber as the medium for light transmission or sensing, and realize hydrogen detection based on the relevant physicochemical properties of hydrogen-sensitive materials, which have excellent characteristics such as intrinsic safety, good stability, small size, high specificity, and easy to network. However, traditional hydrogen-sensitive materials such as Pd metal usually require a large thickness to obtain good performance, but this will shorten the service life of the sensor. In response to this issue, a hydrogen sensor based on hyperbolic metamaterials and ultrathin Pd films is proposed. The control of the Pd film thickness to be less than 0.02 μm ensures that mechanical deformation does not occur during the formation of hydrides in the Pd film. The calculations indicate that the sensor sensitivity can be maintained at approximately 2300 even when the thickness of the palladium film is reduced to 0.011 μm. This work provides a promising solution for high-performance optical hydrogen detection, characterized by high sensitivity, low latency, and low cost.