Lossy mode resonance generated by titanium dioxide nanoarray: a comprehensive theoretical research

The lossy mode resonance (LMR)-based optical fiber waveguide based on titanium dioxide nanoarrays was discovered and researched for the first time in this paper. Two kinds of waveguide coating structures, titanium dioxide nanoarrays and nanofilms-nanoarrays systems, were researched using finite element method, where the localized field distribution, the mode transmission characteristics and measurement sensitivities of surrounding refractive index were researched in detail. In the former structure, there exists a localized electromagnetic field that can be generated by both TE and TM polarization modes around nanoarrays. By increasing the diameters of nanoparticles and decreasing the intervals of nanoarrays, the resonance wavelength will redshift and the measurement sensitivity will be enhanced. In the latter structure, the localized electromagnetic field can be obviously enhanced due to the mode coupling between nanofilms and nanoarrays. In addition, the measurement sensitivity of refractive index was 5179 nm/RIU in the range of 1.333–1.343, which is two times higher than that of the structure without TiO₂ nanoarrays. This paper opened up a door to study the LMR generated by semiconductor nanoparticles, which is useful in the research of electromagnetic resonance-based sensors in nanoscales. (paper)