ABSTRACT
In spite of the fact that Lossy-mode resonance (LMR)-based sensors is still a young research field, one can conclude that LMR could become a competitor of other traditional optical sensing platforms such as surface Plasmon resonance (SPRs), long-period fiber gratings, or micro-ring resonators for designing humidity sensors. In this chapter, we analyze the features of the Lossy mode resonance and the conditions of its appearance. It was shown that LMR-based devices can be realized using films of metal oxides such as indium tin oxide (ITO), titanium dioxide (TiO2), or indium oxide (In2O3) instead of noble metals. The analysis carried out has shown that LMR-based sensors in comparison with the SPR-based devices have a set of undeniable advantages: (1) To produce LMR-based sensors, noble metals are not needed, (2) When the material is properly selected at the LMR measurement, it is possible to refuse the usage of an optical polarizer, and (3) The spectral position of LMRs can be fine-tuned just by changing the thickness of the lossy coating. Features of the LMR-based sensor design, including the development of humidity sensors are also considered. This consideration includes choosing an adequate material, determination of the optimal coating thickness, selection of optimum angle for exciting LMRs, and optimization of optical fiber waveguides. Humidity-sensitive materials used in the sensors are also analyzed in this chapter.
