Enhancing imaging capabilities with a high-sensitivity multichannel optical filter

Abstract

This research introduces a high-sensitivity multichannel optical filter with combined filtering and imaging capabilities, enabling the separation of wavelengths from visible to near-infrared light into distinct colors. The device design comprises a metal-insulator-metal (MIM) straight waveguide coupled to six pairs of overlapping resonators. The transmittance properties and electromagnetic field distributions are analyzed by varying the geometrical sizes using the finite-element method. The designed structure effectively filters out four to fifteen color channels with a narrow full width at half maximum of approximately 2–6 nm. It provides precise multichannel transmittance wavelength selectivity with high color purity, spanning from visible to near-infrared. Additionally, this structure serves as a plasmonic refractive index sensor, demonstrating impressive sensitivity, figure of merit, quality factor, and dipping strength values of 1450 nm/RIU, 241.67 1/RIU, 259.11, and 81.89 %, respectively. These characteristics highlight the excellent sensing performance of the proposed structure, offering significantly higher resolution and smaller dimensions compared to conventional systems.