All-optical Multiplexed Meta-Differentiator for Tri-mode Surface Morphology Observation.

Current optical differentiators are generally limited to realizing a single differential function once fabricated. Herein, we propose a minimalist strategy in designing multiplexed differentiators (1 st - and 2 nd -order differentiations), implemented with a Malus metasurface consisting of single-sized nanostructures, thus improving the functionality of optical computing devices without the cost of complex design and nanofabrication. We found that the proposed meta-differentiator exhibits excellent differential-computation performance and can be used for simultaneous outline detection and edge positioning of objects, corresponding to the functions of the 1 st - and 2 nd -order differentiations respectively. Experiments with biological specimens showcase that we can not only identify boundaries of biological tissues, but also highlight the edge information for realizing high-precision edge positioning. Our study provides a paradigm in designing all-optical multiplexed computing meta-devices, and initiates tri-mode surface morphology observation by combining meta-differentiator with optical microscopes, which can find their applications in advanced biological imaging, large-scale defect detection, and high-speed pattern recognition, etc. This article is protected by copyright. All rights reserved.