Enhancement of lossy mode resonance sensing properties by the introduction of an intermediate low-refractive-index layer

Devices based on the lossy mode resonance (LMR) effect have found numerous sensing applications. Herein, the enhance-ment of the sensing properties by the introduction of an intermediate layer between the substrate and the LMR-supporting film is discussed. Experimental results for a silicon oxide (SiO2) layer of tuned thickness between a glass slide substrate and a thin film of titanium oxide (TiO2) prove the possibility of significantly increasing the LMR depth and the figure of merit (FoM) for refractive index sensing appli-cations, which is supported by a numerical analysis using the plane wave method for a one-dimensional multilayer wave -guide. The application of the intermediate layer allows the introduction of a new, to the best of our knowledge, degree of freedom into the design of LMR-based sensors, resulting in improved performance for demanding fields such as chemi-cal sensing or biosensing.& COPY; 2023 Optica Publishing Group