Holographic laser fabrication of 3D artificial compound μ-eyes

The demand for fast optical image acquisition without movable optical elements (e.g., for self-driving car technology) can be met using bioinspired 3D compound eyes. 3D laser processing strategies enable designable 3D structuring but suffer from low fabrication efficiency, which significantly limits their applications in producing complex 3D optical devices. Herein, we demonstrate a versatile yet simple wet-etching-assisted holographic laser fabrication method for the development of 3D compound eyes. Artificial compound μ eyes can be readily fabricated by programming a 3D spot array for the parallel ablation of a curved fused silica surface, followed by controllable etching in a hydrofluoric (HF) acid solution. A 3D-concave-lens array made on a curved surface over an area of 100 μ m cross-section with each lenslet of 10 μ m radius was fabricated with high fidelity and excellent imaging/focusing quality. The resultant 3D-concave-lens can serve as a hard template for the mass production of soft compound eyes through soft lithography. Additionally, using a generative adversarial network (GAN)-based deep learning algorithm, image restoration was conducted for each lenslet, which retained a large field of view and significantly improved image quality. This method provides a simple solution to the requirements of compound μ -eyes required by Industry 4.0.