Plasmon-Induced Transparency in an Asymmetric Bowtie Structure.

Plasmon-induced transparency is an efficient way to mimic electromagnetically induced transparency, which can eliminate the opaque effect of medium to the propagating electromagnetic wave. We proposed an aperture-side-coupled asymmetric bowtie structure to realize on-chip plasmon-induced transparency in optical communications band. The plasmon-induced transparency results from the strong coupling between the detuned bowtie triangular resonators. Either of the resonator works as a Fabry-Perot cavity with compact dimensions. The transparent peak wavelength can be easily controlled due to its strong linear relation with the resonator height. The ratio of absorption valley to the transparent peak can be more than 10 dB. Moreover, with excellent linearity of shifting wavelength to sensing material index, the device has great sensing performance and immunity to the structure deviations.