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The advancement of super-resolution techniques is essential to the progress of cell and molecular biology. This work presents an overview of the fundamentals and development of Plasmonic Electronically Addressable super-Resolution (PEAR) as a novel super-resolution technique. PEAR aims to improve on limitations faced by currently established methods. PEAR uses an active plasmonic element which is modulated by passing an electric current through the nanostructure, this modulated electric current causes changes in the electrical near field at the modulation frequency. Using a homodyne detection scheme, with the modulation frequency as a reference, sub-diffraction limit spatial information can be transferred into the far field. Recording changes in the modulated light levels allows an image of a sample’s surface to be constructed. PEAR offers a unique advantage over established methods. It ties the spatial resolution of the resulting image to the physical size of the active plasmonic element which, in its simplest, form consists of a constriction in a silver thin film, allowing tuning and de-tuning of the plasmonic resonance when heated. Passing an alternating current through the nanostructure causes changes to the surface plasmon resonance condition. Hence, modulating the electric near field localized to the vicinity of the active plasmonic element experiencing Joule heating. While these changes are of the order of a few percent relative to the overall light levels, the encoded modulation allows the use of a lock-in amplifier to extract changes in the light level at the modulation frequency far below the noise floor. As fluorescent material interacts with this modulated electric near-field it will transfer local information into the far-field, which can be collected using standard optics. As the modulation is highly localized to the active plasmonic element, only the area of fluorescent material directly interacting with the active plasmonic element out-couples the light encoded with the modulation frequency. This directly connects the resolution of the imaging technique to the geometry of the active plasmonic element. By scanning a fluorescent sample over the active plasmonic element in a raster fashion, a map of the localized information is compiled to form an image of the sample’s surface. The PEAR method provides a non-destructive, bio-compatible imaging method which is operational in air, with ease of scalability into multi-channel acquisition in order to reduce acquisition time while maintaining signal to noise ratio. Combining these advantages with the ability to tie the resolution to the physical size of the active plasmonic element makes the PEAR imaging method unique among other imaging technologies at the forefront of super-resolution imaging.
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