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Optical spatial filtering with plasmonic directional image sensors

Authors :
Jianing Liu
Hao Wang
Leonard C. Kogos
Yuyu Li
Yunzhe Li
Lei Tian
Roberto Paiella
Source :
Optics Express. 30:29074
Publication Year :
2022
Publisher :
Optica Publishing Group, 2022.

Abstract

Photonics provides a promising approach for image processing by spatial filtering, with the advantage of faster speeds and lower power consumption compared to electronic digital solutions. However, traditional optical spatial filters suffer from bulky form factors that limit their portability. Here we present a new approach based on pixel arrays of plasmonic directional image sensors, designed to selectively detect light incident along a small, geometrically tunable set of directions. The resulting imaging systems can function as optical spatial filters without any external filtering elements, leading to extreme size miniaturization. Furthermore, they offer the distinct capability to perform multiple filtering operations at the same time, through the use of sensor arrays partitioned into blocks of adjacent pixels with different angular responses. To establish the image processing capabilities of these devices, we present a rigorous theoretical model of their filter transfer function under both coherent and incoherent illumination. Next, we use the measured angle-resolved responsivity of prototype devices to demonstrate two examples of relevant functionalities: (1) the visualization of otherwise invisible phase objects and (2) spatial differentiation with incoherent light. These results are significant for a multitude of imaging applications ranging from microscopy in biomedicine to object recognition for computer vision.

Details

ISSN :
10944087
Volume :
30
Database :
OpenAIRE
Journal :
Optics Express
Accession number :
edsair.doi.dedup.....3b01c260cfaced7dfff6f075889b1b9d
Full Text :
https://doi.org/10.1364/oe.460556