Bioinspired Compound Eyes for Diffused Light-Harvesting Application

Biomimetic Compound Eyes with Gradient Ommatidium Arrays

Compound eyes are high-performing natural optical perception systems with compact configurations, generating extensive research interest. Existing compound eye systems are often combinations of simple uniform microlens arrays; there are still challenges in making more ommatidia on the compound eye surface to focus to the same plane. Here, a biomimetic gradient compound eye is presented by artificially mimicking dragonflies. The multiple replication process efficiently endows compound eyes with the gradient characteristics of dragonfly compound eyes. Experimental results show that the manufactured compound eye allows multifocus imaging by virtue of the gradient ommatidium array arranged closely in a honeycomb pattern while ensuring excellent optical properties and compact configurations. Thousands of ommatidia showing a gradient trend at the millimeter scale while remaining relatively uniform at the micron scale have gradient focal lengths ranging from 260 to 450 μm. This gradient compound eye allows more ommatidia to focus on the same plane than traditional uniform compound eyes, which have experimentally been shown to capture more than 1100 in-plane clear images simultaneously, promising potential applications in micro-optical devices, optical imaging, and biochemical sensing.

Superhydrophobic and easy-to-clean full-packing nanopatterned microlens array with high-quality imaging

The high-quality imaging and easy cleaning property of microlens array (MLA) are two very important factors for its outdoor work. Herein, a superhydrophobic and easy-to-clean full-packing nanopatterned MLA with high-quality imaging is prepared by thermal reflow together with sputter deposition. Scanning electronic microscopy (SEM) images demonstrate that the sputter deposition method can improve 84% packing density of MLA prepared by thermal reflow to 100% and add nanopattern on the surface of microlens. The prepared full-packing nanopatterned MLA (npMLA) possess clear imaging with a significant increase of signal-to-noise ratio and higher transparency compared with the MLA prepared by thermal reflow. Besides for excellent optical properties, the full-packing surface displays a superhydrophobic property with a contact angle of 151.3°. Further, the full-packing contaminated by chalk dust become easier to be cleaned by nitrogen blowing and deionized water. As a result, the prepared full-packing is considered to be potential for various applications in the outdoor.