Creation and preservation of superoscillation in a dielectric optical waveguide

Superoscillation refers to a phenomenon where a band -limited wave locally oscillates faster than its highest Fourier component. Current research on optical superoscillations predominantly lies on the basis of free-space waves. As the optical waveguides play a key role in energy and information transportation, guided waves with precisely controlled deep-subwavelength features offers unprecedented flexibility for applications. In this Letter, we numerically show that, by superimposing eigenmodes of a multimode SiO2 waveguide and forcing the resultant field to pass through a set of pre-determined points, superoscillatory fields in various shapes can be formed in preset cross-sectional planes. Furthermore, by padding prescribed intensities in multiple cross sections, we successfully create a persistent superoscillatory saddle. (c) 2023 Optica Publishing Group it allows out beat of light cial configurations, The used superoscillation cal microscopy extended pulsation for