Design and realization of high-quality multiplet independent resonance modes in a plasmonic waveguide structure.

Multiplet independent resonance modes can be used to control light–matter interactions beyond the capability of conventional optical resonators. Here we present the design and fabrication of multiplexed gratings in a plasmonic waveguide structure to realize multiplet independent resonance modes. Based on the optimally chosen, low-loss plasmonic TM1 waveguiding mode, the multiplet resonance modes demonstrate relatively high-quality factors, field enhancements, overlapping resonance fields, and identical polarization states, advantageous to resonant control and enhancement of light–matter interactions. By adjusting structure parameters of the constitutive gratings, the respective resonance positions and their resonance intensities can be independently adjusted. Experimentally, the plasmonic structures with multiplexed gratings are fabricated, based on multi-exposure holographic lithography processes, which demonstrate arbitrarily adjustable doublet or triplet resonance modes. • Here we report a plasmonic waveguide structure with multiplexed gratings. • The structures demonstrate multiplet independent resonance modes. • The multiplet resonance positions can be independently and arbitrarily adjusted. • The multiplet modes have high quality factors and overlapping mode fields, etc. • The structures are fabricated and the results are experimentally verified. [ABSTRACT FROM AUTHOR]