Hydrogen sensor based on surface plasmon polaritons in palladium layer structure

¹ School of Science, Beijing University of Posts and Telecommunications - 100876, Beijing, China
² China Mobile (Chengdu) Industrial Research Institute (CMII) - 610213, Sichuan, China
³ China Mobile Group Gansu, Ltd - NO. 201 Minzhu East Road, Lanzhou, Gansu, 730030, China
⁴ Modern Post School, Beijing University of Posts and Telecommunications - 100876, Beijing, China

Received: 17 January 2024
Accepted: 4 March 2024

Abstract

We design a new hydrogen (H₂) sensor composed of palladium (Pd) layer structure. Pd can absorb H₂ and turns to Pd-H. The dielectric constant of Pd is totally different from the one of Pd-H. By calculating the propagation length of the layer structure, we find that the difference of the propagation lengths between the structure with Pd and the structure with Pd-H reaches ten times the wavelength in a certain condition. With the number of the layers increasing, another new mode appears and the dissipation of our proposed structure also linearly increases. There is a worst number of the layers that make the difference of the propagation lengths shortest. This shows the competition between the dissipation of the structure and the coupling of surface plasmon polaritons among the layers. In order to achieve the function of H₂ detecting, we set the length of the structure at minimum of L_Pd and at a certain working wavelength. By adding the concentration of H₂, light will emit or not emit . Our proposed technique has a large difference of propagation lengths and is quite sensitive to H₂, which can be used as a hydrogen sensor.