UBC Theses and Dissertations
Characterizing surface wave interactions in finite superlens systems to improve imaging performance Splawinski, Marek Jan
High resolution lenses have numerous applications in the fields of manufacturing and imaging. Surging industrial demand for increased lensing resolution have pushed conventional imaging techniques to their performance limits. To meet this burgeoning industrial need, a comprehensive selection of super-resolution imaging technologies have been spurred into recent research and development. One of the most promising new technologies under investigation are exotic, super-resolution capable lenses known as superlenses. Superlenses that are able to generate sub-wavelength resolution images can be realized by flat slabs of double-negative (both ε < 0 and µ < 0) or single-negative (either ε < 0 or µ < 0) media. These negative material slabs restore the amplitudes of fine detail carrying incident evanescent waves to push imaging resolution beyond that which can be achieved by the focusing of propagating waves alone. Amplification of incident evanescent waves through a superlens slab is delicately dependent on the off-resonant excitation of coupled surface plasmons across the slab's extent. These high surface wave amplitudes intensify minor electromagnetic interactions that are otherwise negligible in conventional imaging systems. In this thesis, we investigate how secondary surface wave interactions introduced by finite transverse-width superlenses and complete superlensing systems can affect lensing performance. By analyzing a simple, 1-D imaging configuration, consisting of a single-negative slab centered between dielectric object and detector half-spaces, we show that inter-component reflections are not necessarily deleterious to imaging performance, but can in fact generate a secondary resonant-amplification mechanism to boost evanescent wave transmission. We then develop simulation and analysis techniques to simultaneously study both the temporal frequency and spatial frequency characteristics of dispersive, finite transverse-width superlenses. Using a full-wave simulation tool provided by COMSOL Multiphysics, we investigate the impact that transverse lens width and lens-corner curvature have on superlens transmission. We show that the surface plasmon resonances of a finite transverse-width superlens, can be modelled using a one-dimensional cavity response, which can be tuned by modifying lens width and corner curvature radius to suppress resonant mode excitation.
Item Citations and Data
Attribution-NonCommercial-NoDerivatives 4.0 International