On‐Chip Super‐Resolution Imaging with Fluorescent Polymer Films

Abstract

Wide field‐of‐view (FOV), label‐free, super‐resolution imaging is demonstrated using a specially designed waveguide chip that can illuminate a sample with multicolor evanescent waves travelling along different directions. The method is enabled by a polymer fluorescent film that emits over a broad wavelength range. Its polygonal geometry ensures coverage over all illumination directions, enabling high‐fidelity image reconstruction while minimizing distortion and image blurring. By frequency shifting and iterative stitching of different spatial frequencies in Fourier space, the reconstruction of 2D samples is achieved without distortion over wide FOVs. The fabrication process is facile and compatible with conventional semiconductor‐fabrication methods. The super‐resolution chip (SRC) can thus be produced with high yield, offering opportunities for potential conjunction of super‐resolution techniques integrated optical circuits or for the development of single‐use diagnostic kits.

Fourier ptychography: current applications and future promises

“…This work offers a compelling example of how FP can provide high-resolution performance, while using low-NA imaging optics. There have also been several novel illumination designs for FP including a ring illuminator for optimal sampling [40,120], laser illumination systems for shorter exposures [40,121], and a waveguide system to provide illumination NAs greater than two [37,122].…”

Far‐Field Superresolution Imaging via Spatial Frequency Modulation

“…This method has been demonstrated in the experiment to agree with the PSF theory result. [51,100,[117][118][119] Very recently, some reports exploit Equation (5) to inversely calculate the PSF of the label-free imaging system, [86,120,121] for example in microsphere lens imaging, in which the integration is performed in the object plane where the coordinates (x o , y o ) are linearly related to the image plane via the magnification M as (…”

“…[119] However, frequency-aliasing is inevitable in the nanowire-ring illumination arrangement due to the lack of control on the illuminating directions. The same group [100] reported an upgraded set up in 2019, by using a polygonal-geometry waveguide chip to reduce the frequency aliasing problem. A fluorescent polymer film beneath the TiO 2 waveguide illuminates the sample with evanescent waves traveling along 16 precisely controlled directions.…”

“…Generally speaking, superresolution microscopy utilizes mainly two kinds of evanescent waves for illumination, evanescent fields at dielectric waveguide boundaries, [97] and surface plasmon polaritons (SPPs) or localized plasmons (LPs) at metal/dielectric interfaces. [98,99] Several papers have reported evanescent-wave-assisted SFS methods using delicately designed structures, including evanescent fields illuminated SFS label-free microscopy, [51,100] evanescent fields illuminated SFS labeled microscopy, [101,102] plasmonic structured illumination microscopy (PSIM), [52,[103][104][105] and localized plasmonic structured illumination microscopy (LPSIM). [106,107] This review aims to provide a systematic discussion on the evanescent-wave-assisted SFM superresolution microscopy techniques (Figure 1) since other reviews only have covered parts of this promising research area.…”

Label-free nanoscopy enabled by coherent imaging with photonic waveguides

“…Details on the algorithm can be found elsewhere. 7 It is important to note that enough overlap of the down-modulated spectra must be present for the algorithm to converge. To determine the effect of limited overlap due to design constraints, simulations have been performed that are presented below.…”