Metamaterial assisted illumination nanoscopy via random super-resolution speckles

Abstract

Structured illumination microscopy (SIM) is one of the most powerful and versatile optical super-resolution techniques. Compared with other super-resolution methods, SIM has shown its unique advantages in wide-field imaging with high temporal resolution and low photon damage. However, traditional SIM only has about 2 times spatial resolution improvement compared to the diffraction limit. In this work, we propose and experimentally demonstrate an easily-implemented, low-cost method to extend the resolution of SIM, named speckle metamaterial-assisted illumination nanoscopy (speckle-MAIN). A metamaterial structure is introduced to generate speckle-like sub-diffraction-limit illumination patterns in the near field with improved spatial frequency. Such patterns, similar to traditional SIM, are then used to excite objects on top of the surface. We demonstrate that speckle-MAIN can bring the resolution down to 40 nm and beyond. Speckle-MAIN represents a new route for super-resolution, which may lead to important applications in bio-imaging and surface characterization.

Organic Hyperbolic Material Assisted Illumination Nanoscopy

“…It has been shown previously that the high‐ k speckle patterns on the top surface of hyperbolic materials can be generated and controlled by tuning the incident non‐uniform illumination patterns. [ 14 , 24 ] In the experimental setup (see details in the Experimental Section and Supporting Information S5), the high‐ k speckle illuminations on the OHM were varied by adding mechanical forces on the multi‐mode fiber with a stepping motor. At the sample plane, the high‐contrast and high‐ k speckles excited the fluorophores in a specimen, and after passing through an emission filter (520/40 nm band‐pass), the fluorescence signal was collected by an sCMOS camera.…”

“…Metamaterial is another platform people used to achieve super resolution. [ 13 , 14 , 15 ] One of the most widely used metamaterials is metal and dielectric multilayer hyperbolic metamaterial (HMM) [ 16 , 17 , 18 ] ( Figure 1 a , left), implemented as the first hyperlens by curving the multilayers and converting the evanescent waves from an object directly into propagating waves. [ 19 , 20 , 21 , 22 , 23 ] In another aspect, HMMs can be also implemented to provide illumination patterns far beyond the diffraction limit.…”

“…[ 19 , 20 , 21 , 22 , 23 ] In another aspect, HMMs can be also implemented to provide illumination patterns far beyond the diffraction limit. [ 14 , 24 , 25 ] Therefore, with such high‐ k illuminations, the metamaterial assisted illumination nanoscopy (MAIN) currently represents a very unique SIM approach with greatly extended resolving power. [ 14 , 26 ] Challenge still remains to obtain images with a resolution beyond 40 nm at visible frequency.…”

Hyperbolic metamaterials: fusing artificial structures to natural 2D materials

“…The development of hyperbolic media that will lead to the improvement of influential optical devices is more extensive than the contents of this review. For example, photostability, low-loss organic HMMs and super-resolution imaging platform using HMMs are being actively investigated [90,[234][235][236][237][238]. The propagation of light in HMMs can be applied to various optical components for collimation [70,239], splitters [240][241][242][243], airy beams [244,245], and even with absorption and scattering for sensing and cloaking [246].…”

“…The characteristic of HMM to support sub-diffractionlimited optical patterns has recently been exploited to improve the resolution of conventional microscopy by combining HMMs with conventional structured illumination microscopy [88][89][90]. HMMs are used to generate sub-diffraction-limited structured light patterns, and the scattering fields are collected in the far-field to improve spatial resolution down to ∼ 40 nm [90]. Sub-diffractional focusing and imaging using natural hyperbolic materials have also been demonstrated to avoid intrinsically high optical losses caused by metals in HMMs [31,67,[91][92][93][94][95].…”