High Sensitivity Hydrogen Sensor via the Coupling of Tamm Plasmon Polaritons and Defect Mode

Optical hydrogen sensors offer high sensitivity, high accuracy, and non-invasive sensing capabilities, making them promising devices in various fields, including the construction of hydrogen fuel cells, storage and transportation, and aerospace. However, to achieve better sensitivity and faster reaction times, such sensors are often constructed as nano-arrays or nano-gratings, leading to increased manufacturing costs and complexity. In this study, we propose and demonstrate a highly sensitive hydrogen sensor based on a multilayer structure. The proposed structure consists of a Pd metal film and a photonic crystal with a defect layer, in which the photonic crystal is designed by an alternating arrangement of Ta2O5 and SiO2, and the material comprising the defect layer is SiO2. With a sensitivity of up to 16,020 at 670 nm, the proposed sensor relies on the coupling of Tamm plasmon polaritons and defect modes. The electric field distribution inside the structure is also provided in order to reveal its physical mechanism. Furthermore, we investigate the effects of the thickness of the defect layer and the angle of incident light on the sensor’s performance. The study results show that the sensor has good fault tolerance in either scenario. The findings of this study open up new possibilities for hydrogen sensor applications.