Sharp Multiple-Phase Resonances in a Plasmonic Compound Grating With Multislits

Transmission properties of light through a plasmonic grating with multislits are investigated. The results show that sharp phase resonance (PR) and multiphase resonance (MPR) for each mode at multiple frequencies are achieved and effectively tailored only by adjusting the slight difference of the multislit widths; the values of the PR dips are almost zero. Based on the field distributions, Fabry-Pérot-resonant and phase-resonant mechanisms have been suggested for the physical origins of the observations qualitatively. In addition, we can realize the control of light spreading through an arbitrary slit; a multichannel selector is modeled and described. Compared with the conventional plasmonic compound grating, this multislit grating with different slit widths has obvious advantages, such as simple structure, single material composition, and better realizability. PR and MPR can be achieved at multiple frequencies.