Artificial Compound Eye with Tunable Properties for Enhancement in Fluorescence Imaging and Raman Detection.

Artificial compound eye (CE) draws inspiration from nature, offering advanced imaging capabilities and an expansive field of view. In this work, an innovative technique is developed for the creation of CE with tunable dimensions. A solution‐based process is employed that involves in situ polymerization of surface nanodroplets prior to soft lithography to produce CE consisting of millions of ommatidia. The fabricated CE comprised of a densely arranged array of microwells, each with a base radius of 5 µm. Situated on a millimeter‐sized spherical dome, the CE can be tailored to arbitrary dimensions, enhancing its adaptability with a wide angular field of view up to 118°. The CE is used to enhance signal detection in fluorescent compounds, reaching a detection limit of 107 times lower concentration than that without using CEs in bulk solution. The signal enhancement capabilities are further utilized for surface‐enhanced Raman spectroscopy by using a portable handheld device, with an enhancement factor of 2. The fabrication technique underscores the advantages of the approach in simplicity, reproducibility, and efficiency in creating CE. The potential applications of CE may be extended to various domains, such as optical sensing, light‐dependent signal enhancement, motion perception, and medical endoscopy. [ABSTRACT FROM AUTHOR]