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Transmission mode synthetic aperture interferometry using a compact coherent imager and switched fiber-optic illumination

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posted on 2024-03-22, 11:17 authored by J Garcia-Armenta, Pablo RuizPablo Ruiz, Russ CoggraveRuss Coggrave, Jeremy CouplandJeremy Coupland
This paper discusses a modular implementation of synthetic aperture interferometry (SAI) using inexpensive telecommunications technologies that can be expanded for use in optical instruments with arbitrarily large fields of view. Exploiting multiple image sensors and multiple illumination sources, transmission and reflection SAI geometries, capable of emulating the phase contrast and interference modes of conventional interference microscopes, are considered. The point-spread and transfer characteristics of these geometries are illustrated for the case of a transmission mode instrument. It is shown that although imaging is strictly field dependent (i.e. shift-variant), the response of modular instruments is periodic and with careful choice of illumination and sensor positioning can be made quasi shift-invariant. We demonstrate SAI in a transmission configuration comprising of a single coherent imager that holographically records the field scattered from a test target sequentially illuminated by 16 different plane waves. This set-up is equivalent to a single module of a larger SAI system and since brightfield regions in the individual reconstructed images overlap, provides an ideal platform to examine the effect of tilt and phase offset errors in the illumination. By applying a first order correction and assuming phase continuity over the overlapping regions, we demonstrate a significant improvement in the SAI reconstruction.

Funding

Synthetic aperture interferometry: High-resolution optical measurement over an exceptionally large field of view

Engineering and Physical Sciences Research Council

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EPSRC Centre for Doctoral Training in Embedded Intelligence

Engineering and Physical Sciences Research Council

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Epigem Ltd

UK Government's Department for Business, Energy and Industrial Strategy (BEIS) through the UK's National Measurement System Programmes at NPL

Future Advanced Metrology Hub

Engineering and Physical Sciences Research Council

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History

School

  • Mechanical, Electrical and Manufacturing Engineering

Published in

Optics and Lasers in Engineering

Volume

172

Publisher

Elsevier

Version

  • VoR (Version of Record)

Rights holder

© Crown Copyright

Publisher statement

This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Acceptance date

2023-09-15

Publication date

2023-09-29

Copyright date

2023

ISSN

0143-8166

eISSN

1873-0302

Language

  • en

Depositor

Prof Jeremy Coupland. Deposit date: 21 March 2024

Article number

107855