  We propose a plasmonic ellipse resonator possessing hybrid modes based on
metal-insulator-metal (MIM) waveguide system. Specially, this nanocavity has
hybrid characteristic of rectangle and disk resonator, therefore supporting
both Fabry-Perot modes (FPMs) and whispering-gallery modes (WGMs). Besides, by
changing the length of major and minor radius of the ellipse, the resonant
wavelengths of FPMs and WGMs can be independently tuned and close to each
other, thus constructing a plasmon-induced transparency (PIT) - like spectrum
profile. Benefitting from this, a dual-band slow light is achieved with one
single resonator. Furthermore, this component can also act as a multi-band
color filter and refractive index sensor. We believe such multi-mode resonator
with ultra-small footprint will play an important role in more compact on-chip
optical circuits in the future.
