A new resonant coupling between an analyte-filled core mode and a supermode of a multi-core holey fiber based plasmonic sensor

摘要

A new resonant coupling between an analyte-filled core mode and a supermode in a multi-core holey fiber recently designed for sensing of benzene is investigated using a finite element method. The dominant electric field of the fundamental core supermode is in a high degree extended at this resonance from the hexagonal solid cores to the analyte (benzene) layer and vice versa for the analyte-filled fundamental core mode. The full width at half maximum (FWHM) bandwidth for the fundamental supermode is 5.3 nm. When the analyte refractive index is increased by 0.001 RIU, the phase matching point is shifted by 4.5 nm toward longer wavelengths, with a corresponding sensitivity better than 2.2 × 10 ~(-5) RIU and a very high value of the signal-to-noise ratio (0.85). The resonance of a fundamental supermode with the first order of surface plasmon resonance mode in the infrared region (λ = 1.33825 μm) can be used together with a resonant coupling between a fundamental supermode with an analyte fundamental mode in visible (λ = 0.6415 μm) part of the spectrum for increasing the performance of the sensor.