Performance Comparison of Lossy Mode Resonance Refractive Index Sensors on Structures Based on Graphene and MoS₂

2D materials such as graphene and MoS₂ play an essential role in improving the performance of optical sensors. This paper numerically investigates a lossy mode resonance (LMR) sensor that uses MgF₂ as its matching layer. The transfer matrix method was chosen to determine the reflectance curve of LMR sensors with different thicknesses of MgF₂ and 2D materials. The computational results show that the LMR sensor generated with s-polarized light has a better resonance. The existence of exciton in MoS₂ also has a dominant contribution to the resulting resonance. There are two absorption peaks around the wavelengths of 610 nm and 652 nm, which are caused by the presence of excitons A and B in MoS₂. When graphene and MoS₂-based chips are compared, MoS₂-based chips display a wider detection range with better signal stability. A sensitivity of 70.37°/RIU can be achieved with MgF₂ (200 nm)/MoS₂ (5 layers). In addition, the proposed LMR sensor has penetration depth that is 2 times higher than the conventional surface plasmon resonance (SPR) sensor, making it possible to replace SPR sensors that rely heavily on gold as their transducer.