Plasmonics for Super Resolution Optical Imaging
Imaging with resolution beyond the diffraction limit has attracted great interest in recent years. In this work, new tools for super resolution optical imaging using plasmonics are developed and demonstrated theoretically and/or experimentally: Localized Plasmonic Structured Illumination Microscopy (LPSIM) and the hyperlens.
The LPSIM technique offers a significant improvement in resolution performance over existing structured illumination microscopy (SIM) methods. An array of plasmonic nano-antennas provide dynamically tunable near-field excitations, which result in a finely structured illumination pattern for a given fluorescent object of interest. The illumination pattern feature sizes are limited only by the antenna geometry, and reconstruction from simple far-field images yields deeply subwavelength resolution. In the initial theoretical and experimental demonstrations shown, resolution is improved 3-fold relative to the diffraction limit. LPSIM is attractive among competing tools due to its wide field of view, bio-compatibility, and video-rate speed capability.
Imaging applications of the hyperlens are also shown in this work. A spherical, metal-dielectric multilayer geometry is used to numerically demonstrate unprecedented radial resolution at 5 nm scale for both imaging and lithography applications. Accuracy far beyond the diffraction limit in the radial direction indicates potential for three-dimensional imaging and lithography applications. Design optimization with regards to several important hyperlens parameters is explored in detail.