Ultrathin film optical coatings for all-optical mathematical operations with ultrahigh numerical aperture

Optical analog computation is garnering increasing attention due to its innate parallel processing capabilities, swift computational speeds, and minimal energy requirements. However, traditional optical components employed for such computations are usually bulky. Recently, there has been a substanti...

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Bibliographic Details
Published in:	Applied physics letters Vol. 123; no. 25
Main Authors:	Wei, Ran, Zhang, Jihua, Jalil, Sohail A, Elkkabash, Mohamed, Guo, Chunlei
Format:	Journal Article
Language:	English
Published:	Melville American Institute of Physics 18-12-2023
Subjects:	Applied physics Edge detection Energy requirements Mathematical analysis Medical imaging Numerical aperture Optical coatings Optical components Parallel processing Thin films
Online Access:	Get full text
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Summary:	Optical analog computation is garnering increasing attention due to its innate parallel processing capabilities, swift computational speeds, and minimal energy requirements. However, traditional optical components employed for such computations are usually bulky. Recently, there has been a substantial shift toward utilizing nanophotonic structures to downsize these bulky optical elements. Nevertheless, these nanophotonic structures are typically realized in planar subwavelength nanostructures, demanding intricate fabrication processes and presenting limitations in their numerical apertures. In this study, we present a three-layer thin-film optical coating different from the conventional Fabry–Pérot nanocavity. Our design functions as a real-time Laplacian operator for spatial differentiation, and it remarkably boasts an ultrahigh numerical aperture of up to 0.7, enabling the detected edges to be sharper and have closely matched intensities. We also experimentally demonstrate its capacity for effective edge detection. This ultracompact and facile-to-fabricate thin-film spatial differentiator holds promising prospects for applications in ultrafast optical processing and biomedical imaging.
ISSN:	0003-6951 1077-3118
DOI:	10.1063/5.0176144