Tunable plasmon-induced transparency in hybrid waveguide-magnetic resonance system.

We present a hybrid waveguide-magnetic resonance system with split ring resonators (SRRs) periodically arranged on top of a waveguide layer. Due to the destructive interference between the electric coupling to the magnetic resonance mode generated in the SRRs and the TE/TM waveguide modes supported by the waveguide layer, double plasmon-induced transparency is obtained at the infrared wavelength. Furthermore, the PIT resonance can be dynamically tuned by the incident angle. An ultranarrow PIT window with an FWHM of 7 nm is observed at the wavelength of 1.448 μm. The group index at the narrow PIT window can reach up to 100. We also demonstrate that the refractive index sensitivity and the figure of merit value can reach up to 640  nm/RIU and 64 in the sensing range, respectively. The proposed hybrid waveguide-magnetic resonance system with a high-quality factor PIT window is promising for efficient optical sensing, optical switching, and slow-light device design.