Fluorescent Nanowire Ring Illumination for Wide-Field Far-Field Subdiffraction Imaging

Abstract

Here we demonstrate an active method which pioneers in utilizing a combination of a spatial frequency shift and a Stokes frequency shift to enable wide-field far-field subdiffraction imaging. A fluorescent nanowire ring acts as a localized source and is combined with a film waveguide to produce omnidirectional illuminating evanescent waves. Benefitting from the high wave vector of illumination, the high spatial frequencies of an object can be shifted to the passband of a conventional imaging system, contributing subwavelength spatial information to the far-field image. A structure featuring 70-nm-wide slots spaced 70 nm apart has been resolved at a wavelength of 520 nm with a 0.85 numerical aperture standard objective based on this method. The versatility of this approach has been demonstrated by imaging integrated chips, Blu-ray DVDs, biological cells, and various subwavelength 2D patterns, with a viewing area of up to 1000 μm^{2}, which is one order of magnitude larger than the previous far-field and full-field nanoscopy methods. This new resolving technique is label-free, is conveniently integrated with conventional microscopes, and can potentially become an important tool in cellular biology, the on-chip industry, as well as other fields requiring wide-field nanoscale visualization.

Single‐Crystalline Perovskite Microlasers for High‐Contrast and Sub‐Diffraction Imaging

“…This is because that the evanescent waves are scattered to far field and are detected. In principle, since the nanoscale objects can be considered as the superposition of a series of sine or cosine gratings, the wave vectors of evanescent waves are changed and thus they are converted to propagating waves, making the high‐resolution spatial information detectable at far field.…”

“…In conventional studies, the nanoparticles are illuminated with external light sources . Both evanescent waves and propagating (transmitted or reflected) waves are generated simultaneously by the scatters and the image contrast is seriously degraded (see Figure b).…”

“…Similar to the single‐crystalline micro‐ and nanolasers, super‐resolution imaging technique has also been thoroughly studied for decades and various of techniques have been developed, e.g. simulated emission depletion (STED) microscopy, structured illumination microscopy (SIM), stochastic optical reconstruction microscopy (STORM), photoactivated localization microscopy (PALM), metamaterial‐assisted hyperlens, microsphere nanoscopy, and nanowire illumination etc . While super‐resolution imaging has been successfully achieved with these techniques, the labeled techniques are usually too complicated and incompatible with solid‐state applications, whereas the label‐free ones require additional nanostructures such as hyperlens or microsphere, which requires complicated nanofabrication process or can only image a few nanoparticles within the focal point.…”

Wavelength‐Tunable Micro/Nanolasers

“…On the other hand, SPP MNLs with biochemical compatibility are also good choices as probe for biological applications . Furthermore, wavelength‐tunable MNLs have potential for pushing super‐resolution forward to full spectral super‐resolution imaging …”

“…The optimization of their parameters, including wavelength, mode, threshold, polarization, etc., is of great significance in the pursuing of practical applications . Compared with wavelength‐fixed MNLs, multiwavelength and wavelength‐tunable MNLs capable of emitting coherent light within a wide spectral range represent particularly interesting opportunities for on‐chip optoelectronics, optical integration, as well as super‐resolution imaging . Over the past decade, tremendous progress has been achieved in the development of wavelength‐tunable MNLs based on bandgap tuning and cavity design ( Figure ).…”