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Super-condenser enables labelfree nanoscopy.

Accepted version
Peer-reviewed

Type

Article

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Authors

Ströhl, Florian 
Opstad, Ida S 
Tinguely, Jean-Claude 
Dullo, Firehun T 

Abstract

Labelfree nanoscopy encompasses optical imaging with resolution in the 100 nm range using visible wavelengths. Here, we present a labelfree nanoscopy method that combines coherent imaging techniques with waveguide microscopy to realize a super-condenser featuring maximally inclined coherent darkfield illumination with artificially stretched wave vectors due to large refractive indices of the employed Si3N4 waveguide material. We produce the required coherent plane wave illumination for Fourier ptychography over imaging areas 400 μm2 in size via adiabatically tapered single-mode waveguides and tackle the overlap constraints of the Fourier ptychography phase retrieval algorithm two-fold: firstly, the directionality of the illumination wave vector is changed sequentially via a multiplexed input structure of the waveguide chip layout and secondly, the wave vector modulus is shortend via step-wise increases of the illumination light wavelength over the visible spectrum. We test the method in simulations and in experiments and provide details on the underlying image formation theory as well as the reconstruction algorithm. While the generated Fourier ptychography reconstructions are found to be prone to image artefacts, an alternative coherent imaging method, rotating coherent scattering microscopy (ROCS), is found to be more robust against artefacts but with less achievable resolution.

Description

Keywords

physics.optics, physics.optics

Journal Title

Opt Express

Conference Name

Journal ISSN

1094-4087
1094-4087

Volume Title

27

Publisher

The Optical Society

Rights

All rights reserved
Sponsorship
Engineering and Physical Sciences Research Council (EP/H018301/1)
Medical Research Council (MR/K02292X/1)
Wellcome Trust (203249/Z/16/Z)
Medical Research Council (MR/K015850/1)
Wellcome Trust (089703/Z/09/Z)