Optical superoscillation technologies beyond the diffraction limit

Abstract

The phenomenon of optical superoscillations first introduced in 2006 (J. Phys. A 39, 6965, 2006) and experimentally identified shortly after (Appl. Phys. Lett. 90, 091119, 2007) describes the rapid subwavelength spatial variations of intensity and phase of light in complex electromagnetic fields formed by interference of several coherent waves. Its discovery stimulated the intense revision of the limits of classical electromagnetism in particular the study of structure of superoscillatory fields in free space including unlimitedly small energy hotspots, phase singularities, energy backflow, anomalously high wavevectors and their intriguing similarities to the evanescent plasmonic fields on metals. In recent years, the better understanding of superoscillatory light has led to the development of superoscillatory lensing, imaging and metrology technologies. Dielectric, metallic and metamaterial nanostructured superoscillatory lenses have been introduced that are able to create hotspots smaller than allowed by conventional lenses. Far-field, label-free non-intrusive deeply subwavelength superresolution imaging and metrology techniques that exploit high light localization and rapid variation of phase in superoscillatory fields have been developed including new approaches based on artificial intelligence. The present paper reviews the fundamental properties of superoscillatory optical fields and examines emerging technological applications of superoscillations.

Structure Rigidification Promoted Ultrabright Solvatochromic Fluorescent Probes for Super-Resolution Imaging of Cytosolic and Nuclear Lipid Droplets

“…Fluorescence imaging has become a robust tool to directly image and monitor vital biomolecules and their associated processes. − Various fluorescent probes with blue to near-infrared emissions have been elegantly synthesized for LD dynamic imaging. − However, most of these LD probes suffer from low resolution (>200 nm) . To overcome this bottleneck, super-resolution imaging techniques have become an indispensable approach to accurately visualize nanoscale structures below 200 nm. − Indeed, a few research groups successfully constructed new LD-specific fluorescent probes for super-resolution imaging using structured illumination microscopy (SIM) and stimulated emission depletion (STED) microscopy. − Interesting imaging results of nano-sized cytosolic LDs with improved higher resolution over traditional confocal laser scanning microscopy (CLSM) have been acquired.…”

Optical Phenomena in Mesoscale Dielectric Particles

“…The high-order Fano resonances in such particles are characterized by the high degree of the field localization, that exceeds the diffraction limit both inside the particle and on its surface. The latter is associated with the formation of regions having high values of the local wavenumber vectors by analogy with the superoscillation effects [9,10]. In accordance with this theory, the local wavenumber vector is a local phase gradient, viz.…”

“…In the authors' opinion, the creation of mesoparticle chains with the required properties using the phase-matching mechanism that relies on the coupling of random quasi-phase-matching with the Mie resonance of the entirely disordered mesostructure is promising [173]. The generation of hot spots, having giant values of the local wavenumber vectors, by use a superoscillation effects [9,10] is extremely promising not only for mesoscale photonics and superresolution imaging, but also for diffractive optics [174], whose research was begun back in 1990 [175].…”

Optical phenomena in mesoscale dielectric particles

“…Also a promising way from our point of view is the way of creating assembled mesoparticles with the required properties based on phase-matching mechanism that relies on the coupling of random quasi-phase-matching with the Mie resonances of the entire disordered mesostructure [171]. The generation of hot spots, having giant values of the local wavenumber vectors, by use a superoscillation effects [9,10] extremely promising not only for mesoscale photonics and superresolution imaging, but also for diffractive optics [172], whose research was begun back in 1990 [173].…”