All-Optical Multiplexed Meta-Differentiator for Tri-Mode Surface Morphology Observation.

Abstract

Current optical differentiators are generally limited to realizing a single differential function once fabricated. Herein, a minimalist strategy in designing multiplexed differentiators (1st - and 2nd -order differentiations), implemented with a Malus metasurface consisting of single-sized nanostructures is proposed, thus improving the functionality of optical computing devices without the cost of complex design and nanofabrication. It is 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 1st - and 2nd -order differentiations respectively. Experiments with biological specimens showcase that boundaries of biological tissues can not only be identified, but also the edge information for realizing high-precision edge positioning is highlighted. The 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.