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This content will become publicly available on July 27, 2024

Title: Asymmetric metasurface photodetectors for single-shot quantitative phase imaging
Abstract The visualization of pure phase objects by wavefront sensing has important applications ranging from surface profiling to biomedical microscopy, and generally requires bulky and complicated setups involving optical spatial filtering, interferometry, or structured illumination. Here we introduce a new type of image sensors that are uniquely sensitive to the local direction of light propagation, based on standard photodetectors coated with a specially designed plasmonic metasurface that creates an asymmetric dependence of responsivity on angle of incidence around the surface normal. The metasurface design, fabrication, and angle-sensitive operation are demonstrated using a simple photoconductive detector platform. The measurement results, combined with computational imaging calculations, are then used to show that a standard camera or microscope based on these metasurface pixels can directly visualize phase objects without any additional optical elements, with state-of-the-art minimum detectable phase contrasts below 10 mrad. Furthermore, the combination of sensors with equal and opposite angular response on the same pixel array can be used to perform quantitative phase imaging in a single shot, with a customized reconstruction algorithm which is also developed in this work. By virtue of its system miniaturization and measurement simplicity, the phase imaging approach enabled by these devices is particularly significant for applications involving space-constrained and portable setups (such as point-of-care imaging and endoscopy) and measurements involving freely moving objects.  more » « less
Award ID(s):
2139451
NSF-PAR ID:
10465428
Author(s) / Creator(s):
; ; ; ;
Date Published:
Journal Name:
Nanophotonics
Volume:
12
Issue:
17
ISSN:
2192-8614
Page Range / eLocation ID:
3519 to 3528
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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